Browsing by Author "Kumar, Kundan"

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Arsenic stress activates MAP kinase in rice roots and leaves
(Elsevier, 2011) Rao, Kudupudi Prabhakara; Vani, Gubbala; Kumar, Kundan; Wankhede, Dhammaprakash Pandhari; Misra, Mohit; Gupta, Meetu; Sinha, Alok Krishna
The toxic metalloid arsenite has become a potential threat to rice growing regions leading to serious contamination in food chain. In the present study effect of different physiological concentration of arsenite that is toxic and triggers the molecular events were evaluated in rice seedlings. Along with severe effect on the growth of rice seedling, production of reactive oxygen species (ROS) and nitric oxide (NO) in arsenite treated rice roots was also observed. Activation of a 42kDa mitogen activated protein kinase (MAPK/MPK) by arsenite was observed in rice leaves and 42 and 44kDa in roots in dose dependent manner. The activated MAPK could be immunoprecipitated with anti-phospho-tyrosine antibody, 4G10. The kinetic of MAPK activation by arsenite was found to be dose dependent. Transcript analysis of MAPK family and immunokinase assay in arsenite treated rice seedling revealed significant level of induction in OsMPK3 transcripts in leaves and OsMPK3, OsMPK4 transcripts in roots. Among MAPK kinase (MKKs) gene family, OsMKK4 transcripts were found to be induced in arsenite treated rice leaves and roots. In-silico homology modeling and docking analysis supported OsMPK3-OsMKK4 interaction. The data indicates that arsenite stress is transduced through MAPK signaling cascade in rice.
Differential regulation of rice mitogen activated protein kinase kinase (MKK) by abiotic stress
(Elsevier B.V., 2008) Kumar, Kundan; Rao, Kudupudi Prabhakara; Sharma, Pallavi; Sinha, Alok Krishna
Mitogen activated protein kinase cascade plays a crucial role in various biotic and abiotic stresses, hormones, cell division and developmental processes. MAP kinase kinase being integral part of this cascade performs an important function of integrating upstream signals to mitogen activated protein kinase for further appropriate cellular responses. We here report cloning of five MAP kinase kinase members from Oryza sativa indica cultivar var. Pusa Basmati 1, namely MAP kinase kinases 1, 3, 4, 6 and 10-2. All these members, except MKK10-2 possess fully canonical motif structures of MAP kinase kinase. The deduced amino acid sequence showed changes at certain position within japonica and indica variety of rice. Analysis of transcript regulation by quantitative real time PCR revealed that these five members are differentially regulated by cold, heat, salinity and drought stresses. MAP kinase kinases 4 and 6 are strongly regulated by cold and salt stresses while MAP kinase kinase 1 is regulated by salt and drought stresses. MAP kinase kinase 10-2 is regulated only by cold stress. The study provides the indication of involvement of specific MAP kinase kinase in different abiotic stress signaling and also possible cross talks that exist during the signaling processes.
Genome-wide characterization of Major Intrinsic Protein (MIP) gene family in Brachypodium distachyon
(Bentham Science, 2018) Saddhe, Ankush Ashok; Shweta; Mosa, Kareem A.; Kumar, Kundan; Prasad, Manoj; Dhankher, Om Parkash
Background: Major intrinsic proteins (MIPs) are membrane channel proteins which maintain water homeostasis and permeable to small molecules across the membrane. Objective: Genome analysis of Brachypodium MIPs (BdMIPs) gene family and in silico studies are based on available bioinformatic tools. Further comparison and evolutionary study of MIPs members were performed within grass family. Method: MIPs sequences were retrieved from Gramene database, aligned and weblogo was generated. Physio-chemical analysis was performed and phylogenetic tree was constructed by neighbor-joining. In silico expression profile of BdMIP genes was searched and image maps were generated by CIMMiner web-based server. Result: Genome wide analysis of B. distachyon identified 33MIP genes and classified into four major groups. Analysis of motifs and transmembrane domains strongly supported their identity as a member of the MIP super family. Duplication analysis revealed that 4 genes were tandemly duplicated and no segmental duplication events in BdMIPs were observed. Prediction of cis-elements in BdMIP promoter region gave more insight into regulation mechanism under hormonal and stress conditions. In silico expression profile under development stages provided insight into expression pattern of BdMIP genes. Conclusion: Total 33 MIPs were predicted in Brachypodium genome. Tandem duplication event was dominant phenomenon over segmental duplication in BdMIPs. Orthology analysis revealed Brachypodium MIP members were close to grass family MIP members compared to Arabidopsis. Compilation of this work will significantly contribute to the understanding of an evolutionary and biological importance of MIP genes in grass family and thus provide a set up for functional genomics studies in Brachypodium.
Genome-wide transcriptome modulation in rice transgenic lines expressing engineered mitogen activated protein kinase kinase 6
(Taylor & Francis Group, 2014) Kumar, Kundan; Sinha, Alok Krishna
Mitogen activated protein kinase kinase (MAPKK) is the central module of MAPK cascade and also point of signal integration and divergence. To investigate the regulatory role of OsMKK6, the regulon of genes controlled by OsMKK6 was constructed by microarray analysis between constitutively activated overexpressing transgenic lines and the wild type rice. Regulated genes were identified in overexpressed constitutively activated OsMKK6 and they were further subdivided on the basis of functional categories, viz. transcription, metabolism, signaling, defense and unknown function. These findings suggest the possible physiological role of OsMKK6 in modulating gene expression and signaling pathways during different stresses.
In silico analysis reveals 75 members of mitogen-activated protein kinase kinase kinase gene family in rice
(Oxford University Press, 2010) Rao, Kudupudi Prabhakara; Richa, Tambi; Kumar, Kundan; Raghuram, Badmi; Sinha, Alok Krishna
Mitogen-Activated Protein Kinase Kinase Kinases (MAPKKKs) are important components of MAPK cascades, which are universal signal transduction modules and play important role in plant growth and development. In the sequenced Arabidopsis genome 80 MAPKKKs were identified and currently being analysed for its role in different stress. In rice, economically important monocot cereal crop only five MAPKKKs were identified so far. In this study using computational analysis of sequenced rice genome we have identified 75 MAPKKKs. EST hits and full-length cDNA sequences (from KOME or Genbank database) of 75 MAPKKKs supported their existence. Phylogenetic analyses of MAPKKKs from rice and Arabidopsis have classified them into three subgroups, which include Raf, ZIK and MEKK. Conserved motifs in the deduced amino acid sequences of rice MAPKKKs strongly supported their identity as members of Raf, ZIK and MEKK subfamilies. Further expression analysis of the MAPKKKs in MPSS database revealed that their transcripts were differentially regulated in various stress and tissue-specific libraries.
Involvement of mitogen activated protein kinase kinase 6 in UV induced transcripts accumulation of genes in phytoalexin biosynthesis in rice
(Springer, 2013) Wankhede, Dhammaprakash Pandhari; Kumar, Kundan; Singh, Pallavi; Sinha, Alok Krishna
BACKGROUND: Ultra violet radiation leads to accumulation of phytoalexins (PA) in rice (Oryza sativa) which are typically accumulated when the plants are infected with rice blast pathogen Magnaporthe oryzae. Although extensive works have been done in elucidating phytoalexin biosynthesis, UV stress signal transduction leading to accumulations of rice phytoalexin is largely unknown.
Over expression of constitutively active mitogen activated protein kinase kinase 6 enhances tolerance to salt stress in rice
(Springer, 2013) Kumar, Kundan; Sinha, Alok Krishna
Salinity is one of the most common abiotic stresses encountered by plants in the environment and transgenic approaches offer new opportunities to improve tolerance. The mitogen activated protein kinase (MAPK) kinase (MKK) is a key component of MAPK cascade that plays important roles in intra and extra cellular signaling in plants. In the present study, a MKK from rice (Oryza sativa), OsMKK6 was functionally characterized in salt stress by transforming its constitutively active form.
Rhythmic expression of mitogen activated protein kinase activity in rice
(Springer, 2009) Rao, Kudupudi Prabhakara; Vani, Gubbala; Kumar, Kundan; Sinha, Alok Krishna
Mitogen activated protein kinase (MAPK) are known to get activated during various stress signals and transduce the message from the cell membrane to the nucleus for appropriate cellular reorganization. Though, a certain basal activity of MAPK is often observed in the control plants. Prolonged exposure of rice plants to lowered or elevated temperature exhibited a rhythm in the activation of MAPKs. We analyzed existence of a possible endogenous rhythm in the activity of MAPKs in rice plants. The plants growing at constant temperature entrained in 16/8 h day-night cycle showed diurnal rhythm in activity. When the activation of MAPK was tested under continuous conditions by shifting plants to continuous darkness for a period of 72 h, the periodic rhythm persisted and followed a circadian pattern. Analysis of the transcripts of group A, B and C members of MAPKs under above conditions by quantitative real time PCR revealed that the members of group C exhibit periodic rhythm. Our data indicates that the MAP kinase activity in rice follows rhythmic expression in a circadian manner.
Rice WNK1 is regulated by abiotic stress and involved in internal circadian rhythm
(Landes Bioscience, 2011) Kumar, Kundan; Rao, Kudupudi Prabhakara; Biswas, Dipul Kumar; Sinha, Alok Krishna
In Mammalian system the WNK (with no lysine kinase) serine-threonine protein kinase gene family is suggested to be involved in regulating ion homeostasis and other pathophysiological processes including cancer, hypertension and renal ion transport. In plant system the information about WNK genes is very poor. However, WNK-like genes have also been identified in plants, including ten in Arabidopsis, designated AtWNK1-AtWNK10. Here we report the cloning and characterization of a homologue of AtWNK1 gene from Oryza sativa indica cultivar Pusa Basmati-1 rice and designated as OsWNK1. The specific feature of this gene is lysine residue in kinase subdomain II, which is essential for the coordination of ATP in the active center and conserved among all other kinases, is absent. OsWNK1 was found to respond differentially under various abiotic stresses like cold, heat, salt, drought. OsWNK1 gene showed rhythmic expression profile under diurnal and circadian conditions at the transcription level. Our data indicates that OsWNK1 in rice might play a role in abiotic stress tolerance and that it is involved in internal rhythm.
Role of α-tocopherol in cellular signaling: α-tocopherol inhibits stress-induced mitogen activated protein kinase activation
(Springer Science, 2011) Hyun, Tae Kyung; Kumar, Kundan; Rao, Kudupudi Prabhakara; Sinha, Alok Krishna; Roitsch, Thomas
Tocopherols belong to the plant-derived poly phenolic compounds known for antioxidant functions in plants and animals. Activation of mitogen-activated protein kinases (MAPK) is a common reaction of plant cells in defense-related signal transduction pathways. We report a novel non-antioxidant function of α-tocopherol in higher plants linking the physiological role of tocopherol with stress signalling pathways. Pre-incubation of a low concentration of 50 μM α-tocopherol negatively interferes with MAPK activation in elicitor-treated tobacco BY2 suspension culture cells and wounded tobacco leaves, whereas pre-incubated BY2 cells with α-tocopherol phosphate did not show the inhibitory effect on stimuli-induced MAPK activation. The decreased MAPK activity was neither due to a direct inhibitory effect of α-tocopherol nor due to the induction of an inhibitory or inactivating activity directly affecting MAPK activity. The data support that the target of α-tocopherol negatively regulates an upstream component of the signaling pathways that leads to stress dependent MAPK activation.
Signal convergence through the lenses of MAP kinases: paradigms of stress and hormone signaling in plants
(Springer, 2013) Kumar, Kundan; Wankhede, Dhammaprakash Pandhari; Sinha, Alok Krishna
Common mechanisms plants use to translate the external stimuli into cellular responses are the activation of mitogen-activated protein kinase (MAPK) cascade. These MAPK cascades are highly conserved in eukaryotes and consist of three subsequently acting protein kinases, MAP kinase kinase kinase (MAPKKK), MAP kinase kinase (MAPKK) and MAP kinase (MAPK) which are linked in various ways with upstream receptors and downstream targets. Plant MAPK cascades regulate numerous processes, including various environmental stresses, hormones, cell division and developmental processes. The number of MAPKKs in Arabidopsis and rice is almost half the number of MAPKs pointing important role of MAPKKs in integrating signals from several MAPKKKs and transducing signals to various MAPKs. The cross talks between different signal transduction pathways are concentrated at the level of MAPKK in the MAPK cascade. Here we discussed the insights into MAPKK mediated response to environmental stresses and in plant growth and development.