Browsing by Author "Meena, Mukesh K."

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Channels hold the key: cyclic nucleotide gated channels (CNGC) in plant biotic stress signaling
(International Society of Endocytobiology, 2015) Meena, Mukesh K.; Vadassery, Jyothilakshmi
Cyclic nucleotide‐gated channels (CNGC) are non‐ selective cation channels opened by the direct binding of cyclic nucleotides and permit diffusion of divalent and monovalent cations, including Ca2+ and K+. The role of CNGC in various plant signaling process is emerging rapidly. Multiple studies have shown that CNGCs are involved in both basal and R gene mediated plant immunity. In this review, we will concentrate on the role of CNGCs in plant immunity, their role in calcium uptake in plants and on their relevance for plant phenotypic plasticity, focusing mostly on the well‐studied Arabidopsis CNGCs.
Expression of chickpea CIPK25 enhances root growth and tolerance to dehydration and salt stress in transgenic tobacco
(Frontiers Media S.A., 2015) Meena, Mukesh K.; Ghawana, Sanjay; Dwivedi, Vikas; Roy, Ansuman; Chattopadhyay, Debasis
Calcium signaling plays an important role in adaptation and developmental processes in plants and animals. A class of calcium sensors, known as Calcineurin B-like (CBL) proteins sense specific temporal changes in cytosolic Ca(2+) concentration and regulate activities of a group of ser/thr protein kinases called CBL-interacting protein kinases (CIPKs). Although a number of CIPKs have been shown to play crucial roles in the regulation of stress signaling, no study on the function of CIPK25 or its orthologs has been reported so far. In the present study, an ortholog of Arabidopsis CIPK25 was cloned from chickpea (Cicer arietinum). CaCIPK25 gene expression in chickpea increased upon salt, dehydration, and different hormonal treatments. CaCIPK25 gene showed differential tissue-specific expression. 5'-upstream activation sequence (5'-UAS) of the gene and its different truncated versions were fused to a reporter gene and studied in Arabidopsis to identify promoter regions directing its tissue-specific expression. Replacement of a conserved threonine residue with an aspartic acid at its catalytic site increased the kinase activity of CaCIPK25 by 2.5-fold. Transgenic tobacco plants overexpressing full-length and the high active versions of CaCIPK25 displayed a differential germination period and longer root length in comparison to the control plants. Expression of CaCIPK25 and its high active form differentially increased salt and water-deficit tolerance demonstrated by improved growth and reduced leaf chlorosis suggesting that the kinase activity of CaCIPK25 was required for these functions. Expressions of the abiotic stress marker genes were enhanced in the CaCIPK25-expressing tobacco plants. Our results suggested that CaCIPK25 functions in root development and abiotic stress tolerance.
Investigation of genes encoding calcineurin B-like protein family in legumes and their expression analyses in chickpea (Cicer arietinum L.)
(PLOS, 2015) Meena, Mukesh K.; Ghawana, Sanjay; Sardar, Atish; Dwivedi, Vikas; Khandal, Hitaishi; Roy, Riti; Chattopadhyay, Debasis
Calcium ion (Ca2+) is a ubiquitous second messenger that transmits various internal and external signals including stresses and, therefore, is important for plants' response process. Calcineurin B-like proteins (CBLs) are one of the plant calcium sensors, which sense and convey the changes in cytosolic Ca2+-concentration for response process. A search in four leguminous plant (soybean, Medicago truncatula, common bean and chickpea) genomes identified 9 to 15 genes in each species that encode CBL proteins. Sequence analyses of CBL peptides and coding sequences (CDS) suggested that there are nine original CBL genes in these legumes and some of them were multiplied during whole genome or local gene duplication. Coding sequences of chickpea CBL genes (CaCBL) were cloned from their cDNAs and sequenced, and their annotations in the genome assemblies were corrected accordingly. Analyses of protein sequences and gene structures of CBL family in plant kingdom indicated its diverse origin but showed a remarkable conservation in overall protein structure with appearance of complex gene structure in the course of evolution. Expression of CaCBL genes in different tissues and in response to different stress and hormone treatment were studied. Most of the CaCBL genes exhibited high expression in flowers. Expression profile of CaCBL genes in response to different abiotic stresses and hormones related to development and stresses (ABA, auxin, cytokinin, SA and JA) at different time intervals suggests their diverse roles in development and plant defence in addition to abiotic stress tolerance. These data not only contribute to a better understanding of the complex regulation of chickpea CBL gene family, but also provide valuable information for further research in chickpea functional genomics.