Publications of NIPGR Scientists

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Author: search.filters.author.Prasad, ManojSubject: search.filters.subject.Drought stress

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    Genome wide investigation and transcriptional profiling of SWEET genes in two contrasting cultivars of foxtail millet under abiotic stresses
    (Elsevier B.V., 2025) Singh, Jitender; Singh, Kajol BM.; Sutar, Rashmi Ranjan; Kumar, Angad; Prasad, Manoj; Thakur, Jitendra K.
    The SWEET (Sugars will eventually be exported transporter) gene family is an important class of sugar transporters that regulates diverse aspects of plant physiology such as apoplastic phloem loading, plant-pathogen interactions and plant responses to abiotic stresses. While majority of the studies on SWEET family in plants have been performed in C3 species, there are limited reports on C4 plants. In this study we conducted genome wide investigation of the SWEET gene family in foxtail millet, a naturally stress tolerant C4 crop. In-silico analysis identified 24 SWEET genes in foxtail millet genome that were classified into 4 distinct clades. Domain analysis revealed the presence of conserved MtN3_slv/PQ-loop domains in all identified SWEET proteins. Interestingly, many SWEET proteins also harboured the prokaryotic SemiSWEET/PQ-loop domain suggesting an evolutionary link to their prokaryotic Semi-SWEET ancestors. In-silico analysis predicted the presence of abscisic acid and drought responsive cis-elements in the promoter region of SWEET genes. Transcriptional analysis under control, drought, and salinity stress revealed differential expression patterns of SWEET genes in stress resistant and stress susceptible foxtail millet cultivars. Moreover, the differential expression of SWEET genes altered the soluble sugar content in leaves and roots under stress conditions suggesting altered carbon re-allocation between source and sink tissues. This study significantly advances our understanding of the SWEET gene family in C4 plants, particularly in foxtail millet, and provides insights into its role in stress tolerance mechanisms and carbohydrate re-allocation under stress conditions.
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    Genetic determinants of drought stress tolerance in Setaria
    (Springer, 2017) Muthamilarasan, Mehanathan; Prasad, Manoj
    Cultivated foxtail millet (Setaria italica) and its wild progenitor (S. viridis) have collectively been considered as tractable model species for studying C4 photosynthesis, stress biology, and biofuel traits. Being cultivated in arid and semiarid tropics of the world, these species are well adapted to harsh environments such as drought, heat, and salinity. This adaptation or acclimation potential of Setaria spp. has drawn research interest, and attempts have been made to dissect the molecular mechanisms of stress tolerance. Compared to other stresses, drought response has been studied extensively in S. italica and many drought-responsive genes encoding for transcription factors, signaling molecules, and enzymes have been identified and characterized. Several genome-wide studies have reported on identification of stress-responsive gene family members, and speculated on the potential for expansion and neofunctionalization of paralogs in these gene families. In this context, this chapter discusses the key genetic determinants identified for stress tolerance in S. italica and demonstrates their use in improving drought tolerance. In addition, strategies for identification of genes underlying stress tolerance are also described. Little effort has so far been made towards understanding the stress-tolerance characteristics of Setaria as compared to studies reported in other crops. Comprehensive functional studies along with the use of integrated -omics approaches are required to elucidate the genetics and genomics of stress tolerance in Setaria, as it is important to develop climate change resilient crops to meet the growing demand for food and feed.
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    Dehydration-responsive miRNAs in foxtail millet: genome-wide identification, characterization and expression profiling
    (Springer, 2016) Yadav, Amita; Khan, Yusuf; Prasad, Manoj
    MAIN CONCLUSION: A set of novel and known dehydration-responsive miRNAs have been identified in foxtail millet. These findings provide new insights into understanding the functional role of miRNAs and their respective targets in regulating plant response to dehydration stress. MicroRNAs perform significant regulatory roles in growth, development and stress response of plants. Though the miRNA-mediated gene regulatory networks under dehydration stress remain largely unexplored in plant including foxtail millet (Setaria italica), which is a natural abiotic stress tolerant crop. To find out the dehydration-responsive miRNAs at the global level, four small RNA libraries were constructed from control and dehydration stress treated seedlings of two foxtail millet cultivars showing contrasting tolerance behavior towards dehydration stress. Using Illumina sequencing technology, 55 known and 136 novel miRNAs were identified, representing 22 and 48 miRNA families, respectively. Eighteen known and 33 novel miRNAs were differentially expressed during dehydration stress. After the stress treatment, 32 dehydration-responsive miRNAs were up-regulated in tolerant cultivar and 22 miRNAs were down-regulated in sensitive cultivar, suggesting that miRNA-mediated molecular regulation might play important roles in providing contrasting characteristics to these cultivars. Predicted targets of identified miRNAs were found to encode various transcription factors and functional enzymes, indicating their involvement in broad spectrum regulatory functions and biological processes. Further, differential expression patterns of seven known miRNAs were validated by northern blot and expression of ten novel dehydration-responsive miRNAs were confirmed by SL-qRT PCR. Differential expression behavior of five miRNA-target genes was verified under dehydration stress treatment and two of them also validated by RLM RACE. Overall, the present study highlights the importance of dehydration stress-associated post-transcriptional regulation governed by miRNAs and their targets in a naturally stress-tolerant model crop.