Arundo, Saccharum, Bagasse, Fibers, Steam explosion, MOE, MOR, IB, TS, and WA
En este trabajo se estudian los parámetros de obtención de tableros sin aporte de adhesivos, a partir de materiales lignocelulósicoscomo son la caña común (Arundodonax L.) y el bagazo de SaccharumofficinarumL. Los tableros propuestos aportan como ventaja el estar libres de emisiones de formaldehído y el no consumir recursos fósiles. Ambas propiedades son importantes en un mercado cada vez más exigente en aspectos medioambientales. En el caso del “ArundodonaxL” se ha partido de cañas silvestres de Tarragona. El bagazo de Saccharumofficinarum utilizado es el subproducto industrial de una destilería de la Isla de la Palma (Canarias). El material crudo ha sido pretratado realizando una “explosión de vapor” en un reactor “batch” a distintas condiciones de severidad. Este material explosionado se ha triturado y prensado en frío de dos formas (en seco y en húmedo). Posteriormente, los tableros prensados en frío y acondicionados a temperatura y HR constantes se han prensado en caliente a diferentes niveles de presión, temperatura y tiempo de prensado. En el proceso de producción a escala de laboratorio de los tableros, se han mejorado algunas de las fases seguidas como el prensado, introduciendo mallas de evacuación de vapor; y se han innovado otros, como la incorporación del prensado en frío y el tratamiento térmico final después de la conformación en caliente. Todo ello para mejorar la homogeneidad y obtener tableros de altas prestaciones mecánicas con estosmateriales. Se ha podido estudiar el efecto de los distintos factores que intervienen en la producción de tableros (Severidad del pretratamiento, temperatura de prensado, presión de prensado y tiempo de prensado), sobre las características físicas y mecánicas de estos tableros(Densidad, MOE, MOR, IB, TS y WA). Con ello se han obtenido las relaciones matemáticas que vinculan a estos factores de producción con las características físicas y mecánicas de los tableros. Puede ser muy importante para la industria el hecho de que los modelos ajustados definidos nos pueden permitir obtener tableros con características prefijadas. También se ha valorado la utilización de material integro explosionado y no lavado y, por tanto, sin ningún lixiviado ni residuo. Los tableros cumplen sobradamente los requerimientos de las norma EN para uso estructural, en todas las características físico-mecánicas estudiadas. Abreviaturas: HR Humedad relativa MOE Módulo de elasticidad en flexión o Módulo de Young MOR Módulo de rotura o Resistencia a la flexión IB Resistencia a la tracción perpendicular a las caras (Internal Bond) TS Hinchamiento WA Absorción de agua
SACCHARUM, ROOT development, SUGARCANE, ROOT growth, HARVESTING, and SURFACE area
Ratooning is an important cultivation practice in sugarcane production around the world, with underground buds on the remaining stalk acting as the source for establishment of a subsequent ratoon crop. However, the optimal depth of cutting during harvest in terms of yield and root growth remains unknown. We carried out a two-year field study to determine the effects of three cutting depths (0, 5 and 10 cm below the surface) ratoon cane root and yield. Results showed that cutting to a depth of 5 cm increased the root fresh weight and root volume by 21–59% and 41–127%, respectively, compared to cutting depths of 0 and 10 cm. Remarkably, cutting to a depth of 5 cm also had a significant effect on the development of fine roots, which is closely linked to cane yield. The effect was particularly noticeable in terms of two root traits, root volume and the surface area of roots with a diameter of 1.0–2.0mm, and root length and the number of root tips in roots with a diameter of 0–0.5mm. As a result, a cutting depth of 5 cm below the surface increased cane yield by 43 and 28% compared to depths of 0 and 10 cm below the surface, respectively. Overall, these findings suggest that a cutting depth of 5 cm is optimal in terms of sugarcane yield, largely due to the enhanced effect on root traits, especially the development of fine roots. These findings will help optimize sugarcane ratoon management and improve the ratoon cycle. [ABSTRACT FROM AUTHOR]
SUGARCANE, CALORIC content of foods, RENEWABLE energy industry, REGULATOR genes, and PLANT metabolism
Background: Sugarcane is capable to store large amounts of sucrose in the culm at maturity hence it became a major source of sucrose for the food and the renewable energy industries. Sucrose, the main disaccharide produced by photosynthesis, is mainly stored in the vacuole of the cells of non-photosynthetic tissues. Two pathways are known to release free sucrose in plant cells, one is de novo synthesis dependent on sucrose phosphate synthase (SPS) and sucrose phosphate phosphatase (S6PP) while the other is regulatory and dependent on sucrose synthase (SuSy) activity. The molecular understanding of genes that give rise to the expression of the enzyme sucrose phosphate phosphatase, responsible for the release of sucrose in the last synthetic step lag behind the regulatory SuSy gene. Results: Sugarcane genome sequencing effort disclosed the existence of a tandem duplication and the present work further support that both S6PP.1 and S6PP_2D isoforms are actively transcribed in young sugarcane plants but significantly less at maturity. Two commercial hybrids (SP80–3280 and R570) and both Saccharum spontaneum (IN84–58) and S.officinarum (BADILLA) exhibit transcriptional activity at three-month-old plants of the tandem S6PP_2D in leaves, culm, meristem and root system with a cultivar-specific distribution. Moreover, this tandem duplication is shared with other grasses and is ancestral in the group. Conclusion: Detection of a new isoform of S6PP resulting from the translation of 14 exon-containing transcript (S6PP_2D) will contribute to the knowledge of sucrose metabolism in plants. In addition, expression varies along plant development and between sugarcane cultivars and parental species. [ABSTRACT FROM AUTHOR]
Dong, Hongxu, Clark, Lindsay V., Jin, Xiaoli, Anzoua, Kossonou, Bagmet, Larisa, Chebukin, Pavel, Dzyubenko, Elena, Dzyubenko, Nicolay, Ghimire, Bimal Kumar, Heo, Kweon, Johnson, Douglas A., Nagano, Hironori, Sabitov, Andrey, Peng, Junhua, Yamada, Toshihiko, Yoo, Ji Hye, Yu, Chang Yeon, Zhao, Hua, Long, Stephen P., and Sacks, Erik J.
PLoS ONE. 1/7/2021, Vol. 16 Issue 1, p1-25. 25p.
FLOWERING time, MISCANTHUS, SUGARCANE, GERMPLASM, SACCHARUM, and LATITUDE
Miscanthus is a close relative of Saccharum and a potentially valuable genetic resource for improving sugarcane. Differences in flowering time within and between Miscanthus and Saccharum hinders intra- and interspecific hybridizations. A series of greenhouse experiments were conducted over three years to determine how to synchronize flowering time of Saccharum and Miscanthus genotypes. We found that day length was an important factor influencing when Miscanthus and Saccharum flowered. Sugarcane could be induced to flower in a central Illinois greenhouse using supplemental lighting to reduce the rate at which days shortened during the autumn and winter to 1 min d-1, which allowed us to synchronize the flowering of some sugarcane genotypes with Miscanthus genotypes primarily from low latitudes. In a complementary growth chamber experiment, we evaluated 33 Miscanthus genotypes, including 28 M. sinensis, 2 M. floridulus, and 3 M. ×giganteus collected from 20.9° S to 44.9° N for response to three day lengths (10 h, 12.5 h, and 15 h). High latitude-adapted M. sinensis flowered mainly under 15 h days, but unexpectedly, short days resulted in short, stocky plants that did not flower; in some cases, flag leaves developed under short days but heading did not occur. In contrast, for M. sinensis and M. floridulus from low latitudes, shorter day lengths typically resulted in earlier flowering, and for some low latitude genotypes, 15 h days resulted in no flowering. However, the highest ratio of reproductive shoots to total number of culms was typically observed for 12.5 h or 15 h days. Latitude of origin was significantly associated with culm length, and the shorter the days, the stronger the relationship. Nearly all entries achieved maximal culm length under the 15 h treatment, but the nearer to the equator an accession originated, the less of a difference in culm length between the short-day treatments and the 15 h day treatment. Under short days, short culms for high-latitude accessions was achieved by different physiological mechanisms for M. sinensis genetic groups from the mainland in comparison to those from Japan; for mainland accessions, the mechanism was reduced internode length, whereas for Japanese accessions the phyllochron under short days was greater than under long days. Thus, for M. sinensis, short days typically hastened floral induction, consistent with the expectations for a facultative short-day plant. However, for high latitude accessions of M. sinensis, days less than 12.5 h also signaled that plants should prepare for winter by producing many short culms with limited elongation and development; moreover, this response was also epistatic to flowering. Thus, to flower M. sinensis that originates from high latitudes synchronously with sugarcane, the former needs day lengths >12.5 h (perhaps as high as 15 h), whereas that the latter needs day lengths <12.5 h. [ABSTRACT FROM AUTHOR]
SACCHARUM, CHROMOSOME duplication, PROTEIN kinases, RECOMBINANT proteins, GENE families, POLYMERASE chain reaction, and SUGARCANE
Background: Calcineurin B-like protein (CBL)-interacting protein kinases (CIPKs) are the primary components of calcium sensors, and play crucial roles in plant developmental processes, hormone signaling transduction, and in the response to exogenous stresses. Results: In this study, 48 CIPK genes (SsCIPKs) were identified from the genome of Saccharum spontaneum. Phylogenetic reconstruction suggested that the SsCIPK gene family may have undergone six gene duplication events from the last common ancestor (LCA) of SsCIPKs. Whole-genome duplications (WGDs) served as the driving force for the amplification of SsCIPKs. The Nonsynonymous to synonymous substitution ratio (Ka/Ks) analysis showed that the duplicated genes were possibly under strong purifying selection pressure. The divergence time of these duplicated genes had an average duplication time of approximately 35.66 Mya, suggesting that these duplication events occurred after the divergence of the monocots and eudicots (165 Mya). The evolution of gene structure analysis showed that the SsCIPK family genes may involve intron losses. Ten ScCIPK genes were amplified from sugarcane (Saccharum spp. hybrids). The results of real-time quantitative polymerase chain reaction (qRT-PCR) demonstrated that these ten ScCIPK genes had different expression patterns under abscisic acid (ABA), polyethylene glycol (PEG), and sodium chloride (NaCl) stresses. Prokaryotic expression implied that the recombinant proteins of ScCIPK3, − 15 and − 17 could only slightly enhance growth under salinity stress conditions, but the ScCIPK21 did not. Transient N. benthamiana plants overexpressing ScCIPKs demonstrated that the ScCIPK genes were involved in responding to external stressors through the ethylene synthesis pathway as well as to bacterial infections. Conclusions: In generally, a comprehensive genome-wide analysis of evolutionary relationship, gene structure, motif composition, and gene duplications of SsCIPK family genes were performed in S. spontaneum. The functional study of expression patterns in sugarcane and allogenic expressions in E. coli and N. benthamiana showed that ScCIPKs played various roles in response to different stresses. Thus, these results improve our understanding of the evolution of the CIPK gene family in sugarcane as well as provide a basis for in-depth functional studies of CIPK genes in sugarcane. [ABSTRACT FROM AUTHOR]
SUGARCANE, TRANSCRIPTION factors, ENERGY crops, SACCHARUM, GENE expression, THRESHOLD energy, LEAF development, and ABIOTIC stress
Background: APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factors play essential roles in plant growth, development, metabolism, and responses to biotic and abiotic stresses. However, few studies concerning AP2/ERF genes in sugarcane which are the most critical sugar and energy crops worldwide. Results: A total of 218 AP2/ERF genes were identified in the Saccharum spontaneum genome. Phylogenetic analysis showed that these genes could be divided into four groups, including 43 AP2s, 160 ERFs and Dehydration-responsive element-binding (DREB) factors, 11 ABI3/VPs (RAV), and four Soloist genes. These genes were unevenly distributed on 32 chromosomes. The structural analysis of SsAP2/ERF genes showed that 91 SsAP2/ERFs lacked introns. Sugarcane and sorghum had a collinear relationship between 168 SsAP2/ERF genes and sorghum AP2/ERF genes that reflected their similarity. Multiple cis-regulatory elements (CREs) present in the SsAP2/ERF promoter were related to abiotic stresses, suggesting that SsAP2/ERF activity could contribute to sugarcane adaptation to environmental changes. The tissue-specific analysis showed spatiotemporal expression of SsAP2/ERF in the stems and leaves of sugarcane at different development stages. In ten sugarcane samples, 39 SsAP2/ERFs were not expressed, whereas 58 SsAP2/ERFs were expressed in all samples. Quantitative PCR experiments showed that SsERF52 expression was up-regulated under salt stress, but suppressed under dehydration stress. SsSoloist4 had the most considerable upregulation in response to treatment with the exogenous hormones ABA and GA. Within 3 h of ABA or PEG6000 treatment, SsSoloist4 expression was up-regulated, indicating that this gene could play a role in the responses to ABA and GA-associated dehydration stress. Analysis of AP2/ERF gene expression patterns under different treatments indicated that SsAP2/ERF genes played an essential role in dehydration and salt stress responses of S. spontaneum. Conclusions: In this study, a total of 218 members of the AP2 / ERF superfamily were identified in sugarcane, and their genetic structure, evolution characteristics, and expression patterns were studied and analyzed. The results of this study provide a foundation for future analyses to elucidate the importance of AP2/ERF transcription factors in the function and molecular breeding of sugarcane. [ABSTRACT FROM AUTHOR]
Marcos, Fernanda C.C., Silveira, Neidiquele M., Mokochinski, João B., Sawaya, Alexandra C.H.F., Marchiori, Paulo E.R., Machado, Eduardo C., Souza, Gustavo M., Landell, Marcos G.A., and Ribeiro, Rafael V.
In Journal of Plant Physiology April 2018 223:9-18
Background: Wild sugarcane Saccharum spontaneum plants vary in ploidy, which complicates the utilization of its germplasm in sugarcane breeding. Investigations on cold tolerance in relation to different ploidies in S. spontaneum may promote the exploitation of its germplasm and accelerate the improvement of sugarcane varieties. Results: A hypoploid clone 12–23 (2n = 54) and hyperploid clone 15–28 (2n = 92) of S. spontaneum were analysed under cold stress from morphological, physiological, and transcriptomic perspectives. Compared with clone 15–28, clone 12–23 plants had lower plant height, leaf length, internode length, stem diameter, and leaf width; depressed stomata and prominent bristles and papillae; and thick leaves with higher bulliform cell groups and thicker adaxial epidermis. Compared with clone 15–28, clone 12–23 showed significantly lower electrical conductivity, significantly higher water content, soluble protein content, and superoxide dismutase activity, and significantly higher soluble sugar content and peroxidase activity. Under cold stress, the number of upregulated genes and downregulated genes of clone 12–23 was higher than clone 15–28, and many stress response genes and pathways were affected and enriched to varying degrees, particularly sugar and starch metabolic pathways and plant hormone signalling pathways. Under cold stress, the activity of 6-phosphate glucose trehalose synthase, trehalose phosphate phosphatase, and brassinosteroid-signalling kinase and the content of trehalose and brassinosteroids of clone 12–23 increased. Conclusions: Compared with hyperploid clone 15–28, hypoploid clone 12–23 maintained a more robust osmotic adjustment system through sugar accumulation and hormonal regulation, which resulted in stronger cold tolerance. [ABSTRACT FROM AUTHOR]