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Background: Sugarcane (Saccharum officinarum L.) is an important sugar crop which belongs to the grass family and can be used for fuel ethanol production. The growing demands for sugar and biofuel is asking for breeding a sugarcane variety that can shed their leaves during the maturity time due to the increasing cost on sugarcane harvest. Results: To determine leaf abscission related genes in sugarcane, we generated 524,328,950 paired reads with RNA-Seq and profiled the transcriptome of new born leaves of leaf abscission sugarcane varieties (Q1 and T) and leaf packaging sugarcane varieties (Q2 and B). Initially, 275,018 transcripts were assembled with N50 of 1,177 bp. Next, the transcriptome was annotated by mapping them to NR, UniProtKB/Swiss-Prot, Gene Ontology and KEGG pathway databases. Further, we used TransDecoder and Trinotate to obtain the likely proteins and annotate them in terms of known proteins, protein domains, signal peptides, transmembrane regions and rRNA transcripts. Different expression analysis showed 1,202 transcripts were up regulated in leaf abscission sugarcane varieties, relatively to the leaf packaging sugarcane varieties. Functional analysis told us 62, 38 and 10 upregulated transcripts were involved in plant-pathogen interaction, response to stress and abscisic acid associated pathways, respectively. The upregulation of transcripts encoding 4 disease resistance proteins (RPM1, RPP13, RGA2, and RGA4), 6 ABC transporter G family members and 16 transcription factors including WRK33 and heat stress transcription factors indicate they may be used as candidate genes for sugarcane breeding. The expression levels of transcripts were validated by qRT-PCR. In addition, we characterized 3,722 SNPs between leaf abscission and leaf packaging sugarcane plants. Conclusion: Our results showed leaf abscission associated genes in sugarcane during the maturity period. The output of this study provides a valuable resource for future genetic and genomic studies in sugarcane. [ABSTRACT FROM AUTHOR]

Background: Grape leaves provide the biochemical substrates for berry development. Thus, understanding the regulation of grapevine leaf metabolism can aid in discerning processes fundamental to fruit development and berry quality. Here, the temporal alterations in leaf metabolism in Merlot grapevine grown under sufficient irrigation and water deficit were monitored from veraison until harvest. Results: The vines mediated water stress gradually and involving multiple strategies: osmotic adjustment, transcript-metabolite alteration and leaf shedding. Initially stomatal conductance and leaf water potential showed a steep decrease together with the induction of stress related metabolism, e.g. up-regulation of proline and GABA metabolism and stress related sugars, and the down-regulation of developmental processes. Later, progressive soil drying was associated with an incremental contribution of Ca2+ and sucrose to the osmotic adjustment concomitant with the initiation of leaf shedding. Last, towards harvest under progressive stress conditions following leaf shedding, incremental changes in leaf water potential were measured, while the magnitude of perturbation in leaf metabolism lessened. Conclusions: The data present evidence that over time grapevine acclimation to water stress diversifies in temporal responses encompassing the alteration of central metabolism and gene expression, osmotic adjustments and reduction in leaf area. Together these processes mitigate leaf water stress and aid in maintaining the berry-ripening program. [ABSTRACT FROM AUTHOR]