CrMPK3, a mitogen activated protein kinase from Catharanthus roseusand its possible role in stress induced biosynthesis of monoterpenoid indole alkaloids

Abstract

BackgroundMitogen 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.ResultsCrMPK3 expressed in bacterial system is an active kinase as it showed auto-phosphorylation and phosphorylation of Myelin Basic Protein. CrMPK3 though localized in cytoplasm, moves to nucleus upon wounding. Wounding, UV treatment and MeJA application on C. roseus leaves resulted in the transcript accumulation of CrMPK3 as well as activation of MAPK in C. roseus leaves. Immuno-precipitation followed by immunoblot analysis revealed that wounding, UV treatment and methyl jasmonate (MeJA) activate CrMPK3. Transient over-expression of CrMPK3 in C. roseus leaf tissue showed enhanced expression of key MIA biosynthesis pathway genes and also accumulation of specific MIAs.ConclusionResults from our study suggest a possible involvement of CrMPK3 in abiotic stress signal transduction towards regulation of transcripts of key MIA biosynthetic pathway genes, regulators and accumulation of major MIAs.

A Positive Feedback Loop Governed by SUB1A1 Interaction with MITOGEN-ACTIVATED PROTEIN KINASE3 Imparts Submergence Tolerance in Rice

“…In-gel kinase activity assays were performed as described previously (Raina et al, 2012). Briefly, 30 mg total protein was fractionated on a 10% polyacrylamide gel containing 0.1% SDS and 0.5 mg mL 21 bovine brain MBP (Sigma Aldrich).…”

Regulation of Specialized Metabolism by WRKY Transcription Factors

“…In Arabidopsis, MPK3 and MPK6 are important in regulating VQ-WRKY protein interactions (Lai et al, 2011;Pecher et al, 2014). In Catharanthus spp., phosphorylation regulates TIA biosynthesis, part of which occurs through the MAPK CrMPK3, an ortholog of Arabidopsis MPK3 (Raina et al, 2012). The work on CrMPK3 suggests that additional WRKY TFs, and probably VQ proteins, are involved in regulation of the TIA pathway.…”

Catharanthus roseusmitogen-activated protein kinase 3 confers UV and heat tolerance toSaccharomyces cerevisiae

“…2C). Since CrMPK3 protein activation was observed in response to UV exposure, 10 better survivals of CrMPK3-transformed yeast during UV exposure substantiates the role of CrMPK3 in UV-mediated signaling. Further, as CrMPK3 rescued the yeast during heat shock, we studied MAPK activation in C. roseus leaves in response to heat shock.…”