Browsing by Author "Raina, Susheel Kumar"

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Catharanthus roseus mitogen-activated protein kinase 3 confers UV and heat tolerance to Saccharomyces cerevisiae
(Taylor & Francis, 2013) Raina, Susheel Kumar; Wankhede, Dhammaprakash Pandhari; Sinha, Alok Krishna
Catharanthus roseus is an important source of pharmaceutically important Monoterpenoid Indole Alkaloids (MIAs). Accumulation of many of the MIAs is induced in response to abiotic stresses such as wound, ultra violet (UV) irradiations, etc. Recently, we have demonstrated a possible role of CrMPK3, a C. roseus mitogen-activated protein kinase in stress-induced accumulation of a few MIAs. Here, we extend our findings using Saccharomyces cerevisiae to investigate the role of CrMPK3 in giving tolerance to abiotic stresses. Yeast cells transformed with CrMPK3 was found to show enhanced tolerance to UV and heat stress. Comparison of CrMPK3 and SLT2, a MAPK from yeast shows high-sequence identity particularly at conserved domains. Additionally, heat stress is also shown to activate a 43 kDa MAP kinase, possibly CrMPK3 in C. roseus leaves. These findings indicate the role of CrMPK3 in stress-induced MIA accumulation as well as in stress tolerance.
CrMPK3, a mitogen activated protein kinase from Catharanthus roseus and its possible role in stress induced biosynthesis of monoterpenoid indole alkaloids
(BMC, 2012) Raina, Susheel Kumar; Wankhede, Dhammaprakash Pandhari; Jaggi, Monika; Singh, Pallavi; Jalmi, Siddhi Kashinath; Raghuram, Badmi; Sheikh, Arsheed Hussain; Sinha, Alok Krishna
Mitogen activated protein kinase (MAPK) cascade is an important signaling cascade that operates in stress signal transduction in plants. The biologically active monoterpenoid indole alkaloids (MIA) produced in Catharanthus roseus are known to be induced under several abiotic stress conditions such as wounding, UV-B etc. However involvement of any signaling component in the accumulation of MIAs remains poorly investigated so far. Here we report isolation of a novel abiotic stress inducible Catharanthus roseus MAPK, CrMPK3 that may have role in accumulation of MIAs in response to abiotic stress.
UV‐B activates a ‘group A’ mitogen activated protein kinase in Oryza sativa
(Springer, 2016) Wankhede, Dhammaprakash Pandhari; Singh, Pallavi; Jaggi, Monika; Rao, Kudupudi Prabhakara; Raina, Susheel Kumar; Sinha, Alok Krishna
Increased level of Ultra violet-B radiation at earth’s surface has several deleterious consequences for plants and ecosystems. Higher UV-B level affects crop plants in several ways and also gives penalty in terms of crop yield. With changing climatic conditions it is crucial to elucidate signal transduction pathway involved in UV-B stress. Here, involvement of mitogen activated protein kinases (MAPKs) in UV-B stress was investigated in rice (Oryza sativa). Transcripts profiling of all 15 rice MAPKs have shown UV-B induced expressions of a few MAPK genes including OsMPK3, OsMPK6, OsMPK4, OsMPK17-1, OsMPK17-2, OsMPK20-1, OsMPK20-4 and OsMPK20-5. In-gel kinase assay as well as immuno-kinase assay showed activation of single MAPK of size ~45 kDa in response to UV-B treatment. Further UV-B responsive activity of rice MAPKs, OsMPK3, OsMPK4 and OsMPK6 was checked using antibodies for the respective orthologs in Arabidopsis which indicated activation of OsMPK3 in UV-B stress. Additionally, GST: OsMPK3 protein showed UV responsive phosphorylation when incubated with crude protein extract from UV exposed plants in an in-vitro phosphorylation assay. These results indicate activation of OsMPK3 in UV-B stress. Further, possible involvement of UV-B responsive OsWRKY89 downstream of MAPK cascade was studied. It was observed that staurosporin and other specific chemical inhibitors of MAPK could attenuate UV-B induced expression of OsWRKY89. OsMPK3 was also found to interact with OsWRKY89 in yeast two-hybrid assay, although the interaction was weak in nature. The present work gives an account of MAPKs in UV-B stress in rice.