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Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Détection, Detection, Detección, Génétique, Genetics, Genética, Marqueur moléculaire, Molecular marker, Marcador molecular, Tige, Stem, Tallo, Triticum aestivum, Gène de résistance, and Resistance gene

Stem rust resistance gene Sr22 transferred to common wheat from Triticum boeoticum and T. monococcum remains effective against commercially prevalent pathotypes of Puccinia graminis f. sp. tritici, including Ug99 and its derivatives. Sr22 was previously located on the long arm of chromosome 7A. Several backcross derivatives (hexaploid) possessing variable sized Sr22-carrying segments were used in this study to identify a closely linked DNA marker. Expressed sequenced tags belonging to the deletion bin 7AL-0.74―0.86, corresponding to the genomic location of Sr22 were screened for polymorphism. In addition, RFLP markers that mapped to this region were targeted. Initial screening was performed on the resistant and susceptible DNA bulks obtained from backcross derivatives carrying Sr22 in three genetic backgrounds with short T. boeoticum segments. A cloned wheat genomic fragment, csIH81, that detected RFLPs between the resistant and susceptible bulks, was converted into a sequence tagged site (STS) marker, named cssu22. Validation was performed on Sr22 carrying backcross-derivatives in fourteen genetic backgrounds and other genotypes used for marker development. Marker cssu22 distinguished all backcross-derivatives from their respective recurrent parents and co-segregated with Sr22 in a Schomburgk (+Sr22)/Yarralinka (―Sr22)-derived recombinant inbred line (RIL) population. Sr22 was also validated in a second population, Sr22TB/Lakin-derived F4 selected families, containing shortened introgressed segments that showed recombination with previously reported flanking microsatellite markers.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Fertilité, Fertility, Fertilidad, Gène, Gene, Gen, Génétique, Genetics, Genética, Oryza, Restauration, Restoration, Restauración, Stérilité mâle cytoplasmique, Cytoplasmic male sterility, and Esterilidad masculina citoplásmica

Although the characterization of genes associated with cytoplasmic male sterility (CMS) and fertility restoration (Rf) has been well documented, the evolutionary relationship between nuclear Rf and CMS factors in mitochondria in Oryza species is still less understood. Here, 41 accessions from 7 Oryza species with AA genome were employed for analyzing the evolutionary relationships between the CMS factors and Rf candidates on chromosome 10. The phylogenetic tree based on restriction fragment length polymorphism patterns of CMS-associated mitochondrial genes showed that these 41 Oryza accessions fell into 3 distinct groups. Another phylogenetic tree based on PCR profiles of the nuclear Rf candidates on chromosome 10 was also established, and three groups were distinctively grouped. The accessions in each subgroup/group of the two phylogenetic trees are well parallel to each other. Furthermore, the 41 investigated accessions were test-crossed with Honglian (gametophytic type) and Wild-abortive (sporophytic type) CMS, and 5 groups were classified according to their restoring ability. The accessions in the same subgroup of the two phylogenetic trees shared similar fertility restoring pattern. Therefore, we conclude that the CMS-associated mitotypes are compatible to the Rf candidate-related nucleotypes, CMS and Rf have a parallel evolutionary relation in the Oryza species.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Africain, African, Africano, Agriculture, Agricultura, Diversité génétique, Genetic diversity, Diversidad genética, Domestication, Domesticación, Gène, Gene, Gen, Génétique, Genetics, Genética, Historique, Case history, Estudio histórico, Multiple, Múltiple, and Oryza sativa

Nucleotide variation in 14 unlinked nuclear genes was investigated in species-wide samples of African rice (Oryza glaberrima) and its wild progenitor (O. barthii). Average estimates of nucleotide diversity were extremely low in both species (θsil = 0.0007 for O. glaberrima; θsil = 0.0024 for O. barthii). About 70% less diversity was found in O. glaberrima than in its progenitor O. barthii. Coalescent simulation indicated that such dramatic reduction of nucleotide diversity in African rice could be explained mainly by a severe bottleneck during its domestication. The progenitor of African rice maintained also low genetic diversity, which may be attributed to small effective population size in O. barthii. Self-pollinating would be another factor leading to the unusually low diversity in both species. Genealogical analyses showed that all O. glaberrima accessions formed a strongly supported cluster with seven O. barthii individuals that were sampled exclusively from the proposed domestication centers of African rice. Population structure and principal component analyses found that the O. glaberrima group was homogeneous with no obvious genetic subdivision, in contrast to the heterogeneous O. barthii cluster. These findings support a single domestication origin of African rice in areas of the Upper Niger and Sahelian Rivers.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Cruciferae, Dicotyledones, Spermatophyta, Agriculture, Agricultura, Analyse corrélation, Correlation analysis, Análisis correlación, Brassica napus, Caractère quantitatif, Quantitative character, Carácter cuantitativo, Déterminisme génétique, Genetic determinism, Determinismo genético, Génétique, Genetics, Genética, and Silique

Rapeseed yield is directly and indirectly influenced by the silique-traits, such as silique length (SL), seeds per silique (SS), seed weight (SW), because the silique is an organ which produced yield and a major photosynthesis organ as well. In this study, a linkage map comprising 150 simple sequence repeat and 195 amplified fragment length polymorphism markers covering 1,759.6 cM was constructed in a doubled haploid population from a cross between two genotypes of 'HZ396' and 'Y106'. In field experiments across three seasons and two locations in China 140 doubled haploid lines and their corresponding parents were evaluated for silique-traits. In total, 26 quantitative trait loci (QTL) were detected, of which 15 were clustered and integrated into 5 pleiotropic unique QTL by meta-analysis. These unique QTL, which in a certain sense reflected the significant positive correlation between SS and SL and the significant negative correlation between SW and SS by the genomic location and effects of QTL detected, were mapped on linkage groups N7, N8 and N13. A trait-by-trait meta-analysis revealed 5, 2 and 3 consensus QTL for SL, SS and SW, respectively. Epistatic effects varied according to the specific traits performed. All the epistatic interactions showed significant additive by additive effects while no significant epistasis by environment effect was identified. These findings provided a better understanding of the genetic factors controlling silique-traits and gained insights into the gene networks affecting silique-traits at QTL level in rapeseed.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Méthodes, théories et divers, Methods, theories and miscellaneous, Angiospermae, Fungi Imperfecti, Fungi, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Carte génétique, Genetic mapping, Mapa genético, Génétique, Genetics, Genética, Haute résolution, High resolution, Alta resolucion, Nécrose, Necrosis, Oryza sativa, Phytotoxine, Phytotoxin, Fitotoxina, Rhizoctonia solani, Sensibilité, Sensitivity, and Sensibilidad

Rhizoctonia solani is a necrotrophic fungal pathogen that causes disease on many crop-plant species. Anastomosis group 1-IA is the causal agent of sheath blight of rice (Oryza sativa L.), one of the most important rice diseases worldwide. R. solani AG1-IA produces a necrosis-inducing phytotoxin and rice cultivar's sensitivity to the toxin correlates with disease susceptibility. Unlike genetic analyses of sheath blight resistance where resistance loci have been reported as quantitative trait loci, phytotoxin sensitivity is inherited as a Mendelian trait that permits high-resolution mapping of the sensitivity genes. An F2 mapping population derived from parent cultivars 'Cypress' (toxin sensitive) and 'Jasmine 85' (toxin insensitive) was used to map Rsn1, the necrosis-inducing locus. Initial mapping based on 176 F2 progeny and 69 simple sequence repeat (SSR) markers located Rsnl on the long arm of chromosome 7, with tight linkage to SSR marker RM418. A high-resolution genetic map of the region was subsequently developed using a total of 1,043 F2 progeny, and Rsnl was mapped to a 0.7 cM interval flanked by markers NM590 and RM418. Analysis of the corresponding 29 Kb genomic sequences from reference cultivars 'Nipponbare' and '93-11' revealed the presence of four putative genes within the interval. Two are expressed cytokinin-O-glucosyltransferases, which fit an apoptotic pathway model of toxin activity, and are individually being investigated further as potential candidates for Rsn1.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Méthodes, théories et divers, Methods, theories and miscellaneous, Angiospermae, Dicotyledones, Spermatophyta, Vitidaceae, Agriculture, Agricultura, Carte génétique, Genetic mapping, Mapa genético, Construction, Construcción, Génétique, Genetics, Genética, Liaison génétique, Genetic linkage, Ligamiento genético, Résistance, Resistance, Resistencia, and Vitis

Downy mildew, caused by the oomycete Plasmopara viticola, is one of the major threats to grapevine. All traditional cultivars of grapevine (Vitis vinifera) are susceptible to downy mildew, the control of which requires regular application of fungicides. In contrast, many sources of resistance to P. viticola have been described in the Vitis wild species, among which is V. amurensis Rupr. (Vitaceae), a species originating from East Asia. A genetic linkage map of V. amurensis, based on 122 simple sequence repeat and 6 resistance gene analogue markers, was established using S 1 progeny. This map covers 975 cM on 19 linkage groups, which represent 82% of the physical coverage of the V. vinifera reference genetic map. To measure the general level of resistance, the sporulation of P. viticola and the necrosis produced in response to infection, five quantitative and semi-quantitative parameters were scored 6 days post-inoculation on the S 1 progeny. A quantitative trait locus (QTL) analysis allowed us to identify on linkage group 14 a major QTL controlling the resistance to downy mildew found in V. amurensis, which explained up to 86.3% of the total phenotypic variance. This QTL was named 'Resistance to Plasmopara viticola 8' (Rpv8).

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Collection, Colección, Génétique, Genetics, Genética, Oryza, Prélèvement, Samplings, Toma de muestra, Salive, and Saliva

The extent of and accessibility to genetic variation in a large germplasm collection are of interest to biologists and breeders. Construction of core collections (CC) is a favored approach to efficient exploration and conservation of novel variation in genetic resources. Using 4,310 Chinese accessions of Oryza sativa L. and 36 SSR markers, we investigated the genetic variation in different sized sub-populations, the factors that affect CC size and different sampling strategies in establishing CC. Our results indicated that a mathematical model could reliably simulate the relationship between genetic variation and population size and thus predict the variation in large germplasm collections using randomly sampled populations of 700―1,500 accessions. We recommend two principles in determining the CC size: (1) compromising between genetic variation and genetic redundancy and (2) retaining the main types of alleles. Based on the most effective scheme selected from 229 sampling schemes, we finally developed a hierarchical CC system, in which different population scales and genetic diversities allow a flexible use of genetic resources. The CC, comprising 1.7% (932) of the accessions in the basic collection, retained more than 85% of both the SSR and phenotypic variations. A mini core collection, comprising 0.3% (189) of the accessions in the basic collection, retained 70.65% of the SSR variation and 76.97% of the phenotypic variation, thus providing a rational framework for intensive surveys of natural variation in complex traits in rice genetic resources and hence utilization of variation in rice breeding.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Amidon, Starch, Almidón, Association, Asociación, Déterminisme génétique, Genetic determinism, Determinismo genético, Gène, Gene, Gen, Génétique, Genetics, Genética, Oryza sativa, Paramètre, Parameter, Parámetro, Synthèse, Synthesis, Síntesis, Viscosité, Viscosity, Viscosidad, Association analysis, Glutinous rice, RVA profile parameters, and Starch synthesis related genes

Starch paste viscosity plays an important role in estimating the cooking, eating, and processing quality of rice. The inheritance of starch paste viscosity in glutinous rice remains undefined. In the present study, 118 glutinous rice accessions were collected, and the genotypes of 17 starch synthesis-related genes (SSRG) were analyzed by using 43 gene-specific molecular markers. Association analysis indicated that 10 of 17 SSRGs were involved in controlling the rapid visco analyzer (RVA) profile parameters. Among these, the PUL gene was identified to play an important role in control of peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV), breakdown viscosity (BDV), peak time (PeT), and paste temperature (PaT) in glutinous rice. Other SSRGs involved only a few RVA profile parameters. Furthermore, interactions between SSRGs were found being responsible for PeT, PaT, and BDV. Some of the RVA parameters, including PKV, HPV, CPV, CSV, and PaT, were mainly governed by single SSRG, whereas other parameters, such as BDV, SBV, and PeT, were controlled by a few SSRGs, functioning cooperatively. Further, three near-isogenic lines (NIL) of a japonica glutinous cv. Suyunuo as genetic background, with PUL, SSIII-1, and SSIII-2 alleles replaced with those of indica cv. Guichao 2, were employed to verify the genetic effects of the various genes, and the results were consistent with those obtained from the association analysis. These findings indicated that starch paste viscosity in glutinous rice had a complex genetic system, and the PUL gene played an important role in determining the RVA profile parameters in glutinous rice. These results provide important information for potentially improving the quality of glutinous rice.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Méthodes, théories et divers, Methods, theories and miscellaneous, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Carte génétique, Genetic mapping, Mapa genético, Cultivar, Déterminisme génétique, Genetic determinism, Determinismo genético, Génétique, Genetics, Genética, Liaison génétique, Genetic linkage, Ligamiento genético, Marqueur moléculaire, Molecular marker, Marcador molecular, Piège, Trap, Trampa, and Saccharum

Sugarcane hybrids are complex aneu-polyploids (2n = 100-130) derived from inter-specific hybridization between ancestral polyploid species, namely S. officinarum L. and S. spontaneum L. Efforts to understand the sugarcane genome have recently been enhanced through the use of new molecular marker technologies. A framework genetic linkage map of Louisiana's popular cultivar LCP 85-384 was constructed using the selfed progeny and based on polymorphism derived from 64 AFLP, 19 SSR and 12 TRAP primer pairs. Of 1,111 polymorphic markers detected, 773 simplex (segregated in 3:1 ratio) and 182 duplex (segregate in 77:4 ratio) markers were used to construct the map using a LOD value of ≥4.0 and recombination threshold of 0.44. The genetic distances between pairs of markers linked in the coupling phase was computed using the Kosambi mapping function. Of the 955 markers, 718 simplex and 66 duplex markers were assigned to 108 co-segregation groups (CGs) with a cumulative map length of 5,617 cM and a density of 7.16 cM per marker. Fifty-five simplex and 116 duplex markers remained unlinked. With an estimated genome size of 12,313 cM for LCP 85-384, the map covered approximately 45.6% of the genome. Forty-four of the 108 CGs were assigned into 9 homo(eo)logous groups (HGs) based on information from locus-specific SSR and duplex markers, and repulsion phase linkages detected between CGs. Meiotic behavior of chromosomes in cytogenetic studies and repulsion phase linkage analysis between CGs in this study inferred the existence of strong preferential chromosome pairing behavior in LCP 85-384. This framework map marks an important beginning for future mapping of QTLs associated with important agronomic traits in the Louisiana sugarcane breeding programs.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Physiologie vegetale et developpement, Plant physiology and development, Germination et dormance, Germination and dormancy, Angiospermae, Compositae, Dicotyledones, Spermatophyta, Acide abscissique, Abscisic acid, Abscísico ácido, Agriculture, Agricultura, Enzyme, Enzima, Germination, Germinación, Gène, Gene, Gen, Génétique, Genetics, Genética, Haute température, High temperature, Alta temperatura, Lactuca, Locus, Substance croissance végétal, Plant growth substance, and Substancia crecimiento vegetal

Thermoinhibition, or failure of seeds to germinate when imbibed at warm temperatures, can be a significant problem in lettuce (Lactuca sativa L.) production. The reliability of stand establishment would be improved by increasing the ability of lettuce seeds to germinate at high temperatures. Genes encoding germination- or dormancy-related proteins were mapped in a recombinant inbred line population derived from a cross between L sativa cv. Salinas and L. serriola accession UC96US23. This revealed several candidate genes that are located in the genomic regions containing quantitative trait loci (QTLs) associated with temperature and light requirements for germination. In particular, LsNCED4, a temperature-regulated gene in the biosynthetic pathway for abscisic acid (ABA), a germination inhibitor, mapped to the center of a previously detected QTL for high temperature germination (Htg6.1) from UC96US23. Three sets of sister BC3S2 near-isogenic lines (NILs) that were homozygous for the UC96US23 allele of LsNCED4 at Htg6.1 were developed by backcrossing to cv. Salinas and marker-assisted selection followed by selfing. The maximum temperature for germination of NIL seed lots with the UC96US23 allele at LsNCED4 was increased by 2―3°C when compared with sister NIL seed lots lacking the introgression. In addition, the expression of LsNCED4 was two- to threefold lower in the former NIL lines as compared to expression in the latter. Together, these data strongly implicate LsNCED4 as the candidate gene responsible for the Htg6.1 phenotype and indicate that decreased ABA biosynthesis at high imbibition temperatures is a major factor responsible for the increased germination thermotolerance of UC96US23 seeds.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Enzyme, Enzima, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Allèle, Allele, Alelo, Chromosome 1, Cromosoma 1, Génotype, Genotype, Genotipo, Génétique, Genetics, Genética, Synthase, Triticum aestivum, Variation, Variations, and Variación

Flour colour measured as a Commission Internationale de l'Eclairage (CIE) b* value is an important wheat quality attribute for a range of end-products, with genes and enzymes of the xanthophyll biosynthesis pathway providing potential sources of trait variation. In particular, the phytoene synthase 1 (Psy1) gene has been associated with quantitative trait loci (QTL) for flour b* colour variation. Several Psy1 alleles on chromosome 7A (Psy-A1) have been described, along with proposed mechanisms for influencing flour b* colour. This study sought to identify evolutionary relationships among known Psy-A1 alleles, to establish which Psy-A1 alleles are present in selected Australian wheat genotypes and establish their role in controlling variation for flour b* colour via QTL analysis. Phylogenetic analyses showed seven of eight known Psy-A1 alleles clustered with sequences from T. urartu, indicating the majority of alleles in Australian germplasm share a common evolutionary lineage. In this regard, Psy-A1a, Psy-A1c, Psy-A1e and Psy-A1p were common in Australian genotypes with flour b* colour ranging from white to yellow. In contrast Psy-A1s was found to be related to A. speltoides, indicating a possible A-B genome translocation during wheat polyploidisation. A new allele Psy-A1t (similar to Psy-Als) was discovered in genotypes with yellow flour, with QTL analyses indicating Psy-A1t strongly influences flour b* colour in Australian germplasm. QTL LOD value maxima did not coincide with Psy-A1 gene locus in two of three populations and, therefore, Psy-A1a and Psy-A1p may not be involved in flour colour. Instead two other QTL were identified, one proximal and one distal to Psy-A1 in Australian wheat lines. Comparison of Psy-A1t and Psy-A1p predicted protein sequences suggests differences in putative sites for post-translational modification may influence enzyme activity and subsequent xanthophyll accumulation in the wheat endosperm. Psy-A1a and Psy-A1p were not involved in flour b* colour variation, indicating other genes control variation on chromosome 7A in some wheat genotypes.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Biosynthèse, Biosynthesis, Biosíntesis, Chromophore, Cromóforo, Déficit, Deficiency, Déficiencia, Gène, Gene, Gen, Génétique, Genetics, Genética, Mutation, Mutación, Oryza sativa, Perte, Loss, Pérdida, Phytochrome, and Fitocromo

In rice (Oryza sativa), a short-day plant, photoperiod is the most favorable external signal for floral induction because of the constant seasonal change throughout the years. Compared with Arabidopsis, however, a large part of the regulation mechanism of the photoperiodic response in rice still remains unclear due mainly to the lack of induced mutant genes. An induced mutant line X61 flowers 35 days earlier than its original variety Gimbozu under a natural photoperiod in Kyoto (35°01'N). We attempted to identify the mutant gene conferring early heading to X61. Experimental results showed that the early heading of X61 was conferred by a complete loss of photoperiodic response due to a novel single recessive mutant gene se13. This locus interacts with two crucial photoperiod sensitivity loci, Se1 and E1. Wild type alleles at these two loci do not function in coexistence with se13 in a homozygous state, suggesting that Se13 is an upstream locus of the Se1 and E1 loci. Linkage analysis showed that Se13 is located in a 110 kb region between the two markers, INDEL3735_1 and INDEL3735_3 on chromosome 1. A database search suggested that the Se13 gene is identical to AK101395 (=OsHY2), which encodes phytochromobilin synthase, a key enzyme in phytochrome chromophore biosynthesis. Subsequent sequence analysis revealed that X61 harbors a 1 bp insertion in exon 1 of OsHY2, which induces a frame-shift mutation producing a premature stop codon. It is therefore considered that the complete loss of photoperiodic response of X61 is caused by a loss of function of the Se13 (OsHY2) gene involved in phytochrome chromophore biosynthesis.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biologie moleculaire et cellulaire, Molecular and cellular biology, Physiologie cellulaire, Cell physiology, Différenciation, maturation, développement, hématopoïèse, Cell differentiation, maturation, development, hematopoiesis, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Annotation, Anotación, Dactylis glomerata, Développement, Development, Desarrollo, Génétique, Genetics, Genética, Marqueur, Marker, and Marcador

Orchardgrass, or cocksfoot [Dactylis glomerata (L.)], has been naturalized on nearly every continent and is a commonly used species for forage and hay production. All major cultivated varieties of orchardgrass are autotetraploid, and few tools or information are available for functional and comparative genetic analyses and improvement of the species. To improve the genetic resources for orchardgrass, we have developed an EST library and SSR markers from salt, drought, and cold stressed tissues. The ESTs were bi-directionally sequenced from clones and combined into 17,373 unigenes. Unigenes were annotated based on putative orthology to genes from rice, Triticeae grasses, other Poaceae, Arabidopsis, and the non-redundant database of the NCBI. Of 1,162 SSR markers developed, approximately 80% showed amplification products across a set of orchardgrass germplasm, and 40% across related Festuca and Lolium species. When orchardgrass subspecies were genotyped using 33 SSR markers their within-accession similarity values ranged from 0.44 to 0.71, with Mediterranean accessions having a higher similarity. The total number of genotyped bands was greater for tetraploid accessions compared to diploid accessions. Clustering analysis indicated grouping of Mediterranean subspecies and central Asian subspecies, while the D. glomerata ssp. aschersoniana was closest related to three cultivated varieties.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Méthodes, théories et divers, Methods, theories and miscellaneous, Angiospermae, Dicotyledones, Solanaceae, Spermatophyta, Agriculture, Agricultura, Caractère agronomique, Agronomic character, Carácter agronómico, Caractère quantitatif, Quantitative character, Carácter cuantitativo, Carte génétique, Genetic mapping, Mapa genético, Chaleur, Heat, Calor, Génétique, Genetics, Genética, Liaison génétique, Genetic linkage, Ligamiento genético, Nécrose, Necrosis, Pomme de terre, Potato, Patata, Solanum tuberosum, Internal heat necrosis, Linkage mapping, QTL, and Tetraploid

Internal heat necrosis (IHN) is a physiological disorder of potato tubers. We developed a linkage map of tetraploid potato using AFLP and SSR markers, and mapped QTL for mean severity and percent incidence of IHN. Phenotypic data indicated that the distribution of IHN is skewed toward resistance. Late foliage maturity was slightly but significantly correlated with increased IHN symptoms. The linkage map for 'Atlantic', the IHN-susceptible parent, covered 1034.4 cM and included 13 linkage groups, and the map for B 1829-5, the IHN-resistant parent, covered 940.2 cM and contained 14 linkage groups. QTL for increased resistance to IHN were located on chromosomes IV, V, and groups VII and X of 'Atlantic', and on group VII of B1829-5 in at least 2 of 3 years. The QTL explained between 4.5 and 29.4% of the variation for mean severity, and from 3.7 to 14.5% of the variation for percent incidence. Most QTL detected were dominant, and associated with decreased IHN symptoms. One SSR and 13 AFLP markers that were linked to IHN were tested in a second population. One AFLP marker was associated with decreased symptoms in both populations. The SSR marker was not associated with IHN in the second population, but was closely linked in repulsion to another marker that was associated with IHN, and had the same (negative) effect on the trait as the SSR marker did in the first population. The correlation between maturity and IHN may be partially explained by the presence of markers on chromosome V that are linked to both traits. This research represents the first molecular genetic research of IHN in potato.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biologie moleculaire et cellulaire, Molecular and cellular biology, Structures cellulaires et fonctions, Cell structures and functions, Récepteurs cellulaires, Cell receptors, Divers, Miscellaneous, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Enzyme, Enzima, Fungi Imperfecti, Fungi, Gramineae, Monocotyledones, Spermatophyta, Transferases, Agriculture, Agricultura, Bipolaris, Cible, Target, Blanco, Clonage moléculaire, Molecular cloning, Clonación molecular, Feuille végétal, Plant leaf, Hoja vegetal, Génétique, Genetics, Genética, Immunité naturelle, Natural immunity, Inmunidad natural, Kinase, Récepteur biologique, Biological receptor, Receptor biológico, Sorghum, Domaine répété riche en leucine, Leucine-rich repeat, Gène de résistance, Resistance gene, Récepteur type Toll, Toll like receptor, Leucine-Rich Repeat Receptor Kinase (LRR-RK), Map-based cloning, Pathogen related gene, R-gene, S-gene, and Toll-like receptor

Target leaf spot is one of the major sorghum diseases in southern Japan and caused by a necrotrophic fungus, Bipolaris sorghicola. Sorghum resistance to target leaf spot is controlled by a single recessive gene (ds1). A high-density genetic map of the ds1 locus was constructed with simple sequence repeat markers using progeny from crosses between a sensitive variety, bmr-6, and a resistant one, SIL-05, which allowed the ds1 gene to be genetically located within a 26-kb region on the short arm of sorghum chromosome 5. The sorghum genome annotation database for BTx623, for which the whole genome sequence was recently published, indicated a candidate gene from the Leucine-Rich Repeat Receptor Kinase family in this region. The candidate protein kinase gene was expressed in susceptible plants but was not expressed or was severely reduced in resistant plants. The expression patterns of ds1 gene and the phenotype of target leaf spot resistance were clearly correlated. Genomic sequences of this region in parental varieties showed a deletion in the promoter region of SIL-05 that could cause reduction of gene expression. We also found two ds1 alleles for resistant phenotypes with a stop codon in the coding region. The results shown here strongly suggest that the loss of function or suppression of the dsl protein kinase gene leads to resistance to target leaf spot in sorghum.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Méthodes, théories et divers, Methods, theories and miscellaneous, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Carte génétique, Genetic mapping, Mapa genético, Cultivar, Génétique, Genetics, Genética, Plant semis, Seedlings, Plantón semillero, Résistance, Resistance, Resistencia, Tige, Stem, Tallo, and Triticum aestivum

Stem rust (caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn.) has re-emerged as a threat to wheat production with the evolution of new pathogen races, namely TTKSK (Ug99) and its variants, in Africa. Deployment of resistant wheat cultivars has provided long-term control of stem rust. Identification of new resistance genes will contribute to future cultivars with broad resistance to stem rust. The related Canadian cultivars Peace and AC Cadillac show resistance to Ug99 at the seedling stage and in the field. The purpose of this study was to elucidate the inheritance and genetically map resistance to Ug99 in these two cultivars. Two populations were produced, an F2:3 population from LMPG/AC Cadillac and a doubled haploid (DH) population from RL6071/ Peace. Both populations showed segregation at the seedling stage for a single stem rust resistance (Sr) gene, temporarily named SrCad. SrCad was mapped to chromosome 6DS in both populations with microsatellite markers and a marker (FSD_RSA) that is tightly linked to the common bunt resistance gene Bt10. FSD_RSA was the closest marker to SrCad (≈1.6 cM). Evaluation of the RL6071/ Peace DH population and a second DH population, AC Karma/87E03-S2B1, in Kenya showed that the combination of SrCad and leaf rust resistance gene Lr34 provided a high level of resistance to Ug99-type races in the field, whereas in the absence of Lr34 SrCad conferred moderate resistance. A survey confirmed that SrCad is the basis for all of the seedling resistance to Ug99 in Canadian wheat cultivars. While further study is needed to determine the relationship between SrCad and other Sr genes on chromosome 6DS, SrCad represents a valuable genetic resource for producing stem rust resistant wheat cultivars.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Caractère agronomique, Agronomic character, Carácter agronómico, Caractère quantitatif, Quantitative character, Carácter cuantitativo, Génétique, Genetics, Genética, Partiel, Partial, Parcial, Race, Raza, Résistance, Resistance, Resistencia, Triticum aestivum, Validation, and Validación

A mapping population of 186 recombinant inbred lines developed from a cross between UC 1110, an adapted California spring wheat, and PI610750, a synthetic derivative from CIMMYT's Wide Cross Program, was evaluated for its response to current California races of stripe rust (Puccinia striiformis f. sp. tritici) in replicated field trials over four seasons (2007-2010) in the northern Sacramento Valley. A genetic map was constructed consisting of 1,494 polymorphic probes (SSRs, DArTs, and ESTs) mapped to 558 unique loci, and QTL analysis revealed the presence of four stripe rust resistance QTL segregating in this population, two from UC1110 (on chromosomes 3BS and 2BS) and two from PI610750 (5AL and 2AS). The two QTL of largest effects (on 3BS and 5AL) were validated in independent populations and their intervals narrowed to 2.5 and 5.3 cM, respectively. The 3BS QTL was shown, by allelism test and genotype, to carry a gene different from the Yr30/Sr2 complex. Mapped position also suggests that the 3BS QTL is associated with a gene different from either Yrns-B1 or YrRub, two stripe rust resistance genes mapped to this region in other studies. The 5AL QTL carries a previously unreported partial stripe rust resistance gene, designated here as Yr48. This paper discusses the individual contributions to resistance of these four QTL, their epistatic interactions, and their potential in durable resistance breeding strategies based on combinations of partial resistance genes.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Génétique, Genetics, Genética, Plomb, Lead, Plomo, Race, Raza, Résistance transfert, Transfer resistance, Resistencia a la transferencia, Tige, Stem, Tallo, Translocation, Translocación, Triticum aestivum, Gène de résistance, and Resistance gene

Stem rust (Puccinia graminis f. sp. tritici Eriks. & E. Henn.) (the causal agent of wheat stem rust) race Ug99 (also designated TTKSK) and its derivatives have defeated several important stem rust resistance genes widely used in wheat (Triticum aestivum L.) production, rendering much of the worldwide wheat acreage susceptible. In order to identify new resistance sources, a large collection of wheat relatives and genetic stocks maintained at the Wheat Genetic and Genomic Resources Center was screened. The results revealed that most accessions of the diploid relative Dasypyrum villosum (L.) Candargy were highly resistant. The screening of a set of wheat-D. villosum chromosome addition lines revealed that the wheat-D. villosum disomic addition line DA6V#3 was moderately resistant to race Ug99. The objective of the present study was to produce and characterize compensating wheat-D. villosum whole arm Robertsonian translocations (RobTs) involving chromosomes 6D of wheat and 6V#3 of D. villosum through the mechanism of centric breakage-fusion. Seven 6V#3-specific EST-STS markers were developed for screening F2 progeny derived from plants double-monosomic for chromosomes 6D and 6V#3. Surprisingly, although 6D was the target chromosome, all recovered RobTs involved chromosome 6A implying a novel mechanism for the origin of RobTs. Homozygous translocations (T6AS·6V#3L and T6AL·6V#3S) with good plant vigor and full fertility were selected from F3 families. A stem rust resistance gene was mapped to the long arm 6V#3L in T6AS·6V#3L and was designated as Sr52. Sr52 is temperature-sensitive and is most effective at 16°C, partially effective at 24°C, and ineffective at 28°C. The T6AS·6V#3L stock is a new source of resistance to Ug99, is cytogenetically stable, and may be useful in wheat improvement.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Cruciferae, Dicotyledones, Spermatophyta, Agriculture, Agricultura, Brassica napus, Génétique, Genetics, Genética, Stérilité mâle, Male sterility, and Esterilidad masculina

Male sterility is of special interest as a mechanism allowing hybrid breeding, especially in important crops such as rapeseed (Brassica napus). Male sterile plants are also suggested to be used as a biological safety method to prevent the spread of transgenes, a risk that is high in the case of rapeseed due to the mode of pollination, out-crossing by wind or insects, and the presence of related, cross-pollinating species in the surrounding ecosystem in Europe. Different natural occurring male sterilities and alloplasmic forms have been tried to be used in rapeseed with more or less success. Due to the difficulties and limitations with these systems, we present a biotechnological alternative: a metabolically engineered male sterility caused by interference with anther-specific cell wall-bound invertase. This is an essential enzyme for carbohydrate supply of the symplastically isolated pollen. The activity of this enzyme is reduced either by antisense interference or by expressing an invertase inhibitor under control of the anther-specific promoter of the invertase with the consequence of a strong decrease of pollen germination ability.

Agronomy, agriculture, phytopathology, Agronomie, agriculture, phytopathologie, Genetics, Génétique, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Genetique des eucaryotes. Evolution biologique et moleculaire, Genetics of eukaryotes. Biological and molecular evolution, Génétique classique, génétique quantitative, hybrides, Classical genetics, quantitative genetics, hybrids, Végétaux, Vegetals, Pteridophyta, spermatophyta, Angiospermae, Gramineae, Monocotyledones, Spermatophyta, Agriculture, Agricultura, Amélioration, Improvement, Mejora, Caractère agronomique, Agronomic character, Carácter agronómico, Caractère quantitatif, Quantitative character, Carácter cuantitativo, Distribution, Distribución, Gène, Gene, Gen, Génome, Genome, Genoma, Génétique, Genetics, Genética, Information, Información, Sorghum, Séquence nucléotide, Nucleotide sequence, and Secuencia nucleótido

A comprehensive analysis was conducted using 48 sorghum QTL studies published from 1995 to 2010 to make information from historical sorghum QTL experiments available in a form that could be more readily used by sorghum researchers and plant breeders. In total, 771 QTL relating to 161 unique traits from 44 studies were projected onto a sorghum consensus map. Confidence intervals (CI) of QTL were estimated so that valid comparisons could be made between studies. The method accounted for the number of lines used and the phenotypic variation explained by individual QTL from each study. In addition, estimated centimorgan (cM) locations were calculated for the predicted sorghum gene models identified in Phytozome (JGI GeneModels SBI v 1.4) and compared with QTL distribution genome-wide, both on genetic linkage (cM) and physical (base-pair/bp) map scales. QTL and genes were distributed unevenly across the genome. Heterochromatic enrichment for QTL was observed, with approximately 22% of QTL either entirely or partially located in the heterochromatic regions. Heterochromatic gene enrichment was also observed based on their predicted cM locations on the sorghum consensus map, due to suppressed recombination in heterochromatic regions, in contrast to the euchromatic gene enrichment observed on the physical, sequence-based map. The finding of high gene density in recombination-poor regions, coupled with the association with increased QTL density, has implications for the development of more efficient breeding systems in sorghum to better exploit hetero-sis. The projected QTL information described, combined with the physical locations of sorghum sequence-based markers and predicted gene models, provides sorghum researchers with a useful resource for more detailed analysis of traits and development of efficient marker-assisted breeding strategies.