Drought Stress-Modulated Alternative Splicing Landscapes in Drought-tolerant and -Sensitive Banana Cultivars

Not Availablevariants have major impact in plant response to drought stress. Alternative splicing a major post-transcriptional modification and its differential sensitivity to drought stress is of paramount importance to resolve complex molecular response of drought stress and to develop drought-resilient crops. In the present study, we analyzed the alternative splicing pattern of drought-tolerant (DT) and -sensitive banana (DS) cultivars under drought conditions and found that the number of spliced transcripts in DS (AAA genome) has increased to about 4.32 folds, while 0.19 fold among all the splicing events were reduced in DT (ABB genome). Categorization of drought -modulated alternative splicing (AS) events revealed that intron retention is the most abundant (42.5%) process, followed by alternative splice acceptor (22.6%), alternative splice donor (12.2%), and exon skipping (4.86%) in DS. Only 40-44% of intron retained transcripts have the protein coding capacity, indicating that their occurrence would participate in drought stress response as modified yet functional proteins. We observed that retained introns were slightly higher in GC content than constitutively spliced introns. The results reveal that the genotype dependent AS pattern may play an important role in drought tolerance in banana. This study will help in deciphering the molecular basis underlying phenotypic differences among tolerant and sensitive banana cultivars.Not Availabl

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Not AvailableLong non-coding RNAs (lncRNAs) are important regulators of gene expression in plant response to biotic and abiotic stresses. The participation of lncRNAs in plant disease resistance in bananas is largely unknown. Therefore, we attempted to identify novel lncRNAs responsive to Mycosphaerella eumusae, a causative agent of Eumusae leaf spot disease and root lesion nematode, Pratylenchus coffeae and their differential expression patterns during stress and normal conditions in respective resistant and sensitive banana genotypes. Illumina paired-end transcriptome sequencing of control and infected samples of resistant and sensitive banana cultivars was performed and the sequence reads assembled into 172434, 201256 transcriptional units (TUs) for M. eumusae and P. coffeae, respectively. The genome-wide analysis for ELSD-responsive lncRNAs led to identification of 5142 novel lncRNAs including 3031-intergenic, 1672-intragenic, and 440 antisense lncRNAs classes collectively from ELSD-resistant and sensitive cultivars. Similarly, 5615 lncRNAs comprised of 3283 intergenic, 1878-intragenic, and 454 antisense classes were identified from P. coffeae-infected resistant and sensitive banana cultivars. Most of the lncRNAs were stress specific, evenly distributed among banana chromosomes and the average length is ranging from 620 to 684 nucleotides. In addition, 1250 and 1284 lncRNAs were differentially expressed to M. eumusae and P. coffeae infections, respectively. The LncRNA–mRNA interaction-based functional role showed lncRNA-mediated downregulation of horcolin, an antifungal protein is likely responsible for ELSD sensitivity in banana cultivars. Furthermore, we identified 100 of these lncRNAs also play a role in drought stress response of banana indicating a possible crosstalk between biotic and abiotic stresses.NPTC-Functional Genomics component of the Indian Council of Agricultural Research (ICAR), India

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Not AvailableIn banana, drought responsive gene expression profiles of drought-tolerant and sensitive genotypes remain largely unexplored. In this research, the transcriptome of drought-tolerant banana cultivar (Saba, ABB genome) and sensitive cultivar (Grand Naine, AAA genome) was monitored using mRNA-Seq under control and drought stress condition. A total of 162.36 million reads from tolerant and 126.58 million reads from sensitive libraries were produced and mapped onto the Musa acuminata genome sequence and assembled into 23,096 and 23,079 unigenes. Differential gene expression between two conditions (control and drought) showed that at least 2268 and 2963 statistically significant, functionally known, non-redundant differentially expressed genes (DEGs) from tolerant and sensitive libraries. Drought has up-regulated 991 and 1378 DEGs and down-regulated 1104 and 1585 DEGs respectively in tolerant and sensitive libraries. Among DEGs, 15.9% are coding for transcription factors (TFs) comprising 46 families and 9.5% of DEGs are constituted by protein kinases from 82 families. Most enriched DEGs are mainly involved in protein modifications, lipid metabolism, alkaloid biosynthesis, carbohydrate degradation, glycan metabolism, and biosynthesis of amino acid, cofactor, nucleotide-sugar, hormone, terpenoids and other secondary metabolites. Several, specific genotype-dependent gene expression pattern was observed for drought stress in both cultivars. A subset of 9 DEGs was confirmed using quantitative reverse transcription-PCR. These results will provide necessary information for developing drought-resilient banana plants.Not Availabl

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Not AvailableEndogenous hormone secretion proteins along with stress and defense proteins play predominant role in banana embryogenesis. This study reveals the underlying molecular mechanism during transition from vegetative to embryogenic state.ICAR, ICAR-NRC