Browsing by Author "Sharma, Manoj K."

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Characterization and phylogenetic analysis of environmental stress responsive SAP gene family encoding A20/AN1 zinc-finger proteins in tomato
(Springer, 2009) Solanke, Amolkumar U.; Sharma, Manoj K.; Tyagi, Akhilesh K.; Sharma, Arun Kumar
Characterization of genes responsive to stress is important for eVorts on improving stress tolerance of plants. To address components involved in stress tolerance of tomato (Solanum lycopersicum), a stress-responsive gene family encoding A20/AN1 zinc Wnger proteins was characterized. In the present study, 13 members of this gene family were cloned from tomato cultivar Pusa Ruby and named as Stress Associated Protein (SAP) genes. Out of 13 genes, 12 have been mapped on their respective chromo- somes. Expression of these genes in response to cold, heat, salt, desiccation, wounding, abscisic acid, oxidative and submergence stresses was analysed. All tomato SAP genes were found to be responsive to one or other type of environ- mental stress. The phylogenetic analysis of these genes, along with their orthologs from Solanaceae species sug- gests the presence of a common set of SAP genes in the studied Solanaceae species. The present study characterizes a SAP gene family, which encodes A20/AN1 zinc Wnger containing proteins from tomato for the Wrst time. Genes showing high expression in response to a particular stress can be exploited for improving stress tolerance of tomato and other Solanaceae members.
Identification, phylogeny and transcript profiling of ERF family genes during development and abiotic stress treatments in tomato
(Springer, 2010) Sharma, Manoj K.; Kumar, Rahul; Solanke, Amolkumar U.; Sharma, Rita; Tyagi, Akhilesh K.; Sharma, Arun K.
Ethylene responsive transcription factors have been shown to be intimately connected to plant development, defense responses and stress signaling pathways and in order to use them for plant improvement, we need to have better understanding of these proteins. In this study, 85 ERF genes have been identified from tomato using raw EST data in various public repositories. Phylogenetic analysis with tomato ERF domains revealed their distribution in all the groups, previously identified in model systems. MEME motif analysis resulted in identification of conserved domains, characteristic to member of each clade, in addition to ERF domain. Expression analysis during vegetative and reproductive stages of development using QPCR and tomato GeneChip arrays, revealed their tissue-specific/preferential accumulation. In total, 57 genes were found to be differentially expressed during temporal stages of tomato fruit development. The expression analysis of 23 ERF family genes representing each clade in response to seven abiotic stress treatments revealed their differential expression in response to more than one abiotic stress treatments. Results suggest that ERF genes play diverse roles in plant's life and comprehensive data generated will be helpful in conducting functional genomics studies to understand their precise role during plant development and stress response.
Transcriptome analysis of rin mutant fruit and in silico analysis of promoters of differentially regulated genes provides insight into LeMADS-RIN-regulated ethylene-dependent as well as ethylene-independent aspects of ripening in tomato
(Springer Science, 2012) Kumar, Rahul; Sharma, Manoj K.; Kapoor, Sanjay; Tyagi, Akhilesh K.; Sharma, Arun K.
A thorough understanding of molecular mechanisms underlying ripening is the prerequisite for genetic manipulation of fruits for better shelf-life and nutritional quality. Mutation in LeMADS-RIN, a MADS-box gene, leads to non-ripening phenotype of rin fruits in tomato. Characterization of ripening-inhibitor (rin) mutant has elucidated important role of ethylene in the regulation of climacteric fruit ripening. A complete understanding of this mutation will unravel novel genetic regulatory mechanisms involved in fruit ripening. In this study, fruit transcriptomes of two genotypes, including a cultivated Indian cultivar Solanum lycopersicum cv. Pusa Ruby and a homozygous line harboring the rin mutation (LA1795) were compared to get better insight into RIN-regulated ethylene-dependent and ethylene-independent events during ripening. Cluster analysis of ripening-related genes indicated a major shift in their expression profiles in rin mutant fruit. A total of 112 genes, exhibiting expression patterns similar to that of LeMADS-RIN in wild-type fruits, showed down regulation of expression in the rin mutant. In silico analysis of putative promoters of these genes for the presence of CArG box along with ERE and ethylene inducibility of these genes revealed that genes lacking CArG box in their regulatory regions could be indirectly regulated by LeMADS-RIN. New regulators of ethylene-dependent aspect of ripening were also identified. In this study, we have made an attempt to distinguish between ethylene-dependent and ethylene-independent aspects of ripening, which will be useful for developing strategies to improve fruit-related agronomic traits in tomato and other crops.