Role of a LAMMER like serine/threonine protein kinase (OsSTPK12.1) in drought tolerance
Student name: Ms Ankita Pandey
Guide: Dr Pallavi Somvanshi
Year of completion: 2014
Host Organisation: Plant Molecular Biology Laboratory (PMBL), International Rice Research Institute (IRRI)
Abstract: Drought has been a major abiotic stress, harnessing rice production, for decades. Research
focusing on generating better drought tolerant rice variety, lead to the identification of a large
effect QTL, qDTY12.1, from WayRarem (a drought sensitive parent). NILs generated in Vandana
background, using MAS, were found to perform better under severe drought. Screening of 1.7 MB
region of the QTL, combined with in silico studies and literature surveys, lead to the identification
of 10 Candidate genes, hypothesized to play vital role in better drought tolerance. OsSTPK12.1,
identified as one of the CGs, was found to be upregulated under drought. Therefore, the aim of this
study was to determine the role of OsSTPK12.1, and the mechanism by which it confers drought
tolerance. Cloning and sequencing of OsSTPK12.1, combined with in silico results, showed
OsSTPK12.1, to have LAMMER motif and hence a LAMMER Kinase which was predicted to
phosphorylate SR proteins and other splicing factors. Further to this, our analysis of splice variants
of OsSTPK12.1, revealed them to be PTC+
, following 50 nucleotide rule and therefore assumed to be
potential targets to Nonsense Mediated Decay. Moreover, 2D PAGE analysis, confirmed the Kinase
activity of OsSTPK12.1, as it was found to in vitro phosphorylate OsNAM12.1, yet another very
important CG from qDTY12.1. This result also strengthens and highlights our hypothesis of a
complex regulation of a complex trait. Furthermore, qPCR analysis of Flagleaf, Panicle and Root
tissues of Heading and Grain filling stages of Vandana, WayRarem and 481B NIL, showed tissue
specific upregulation of OsSTPK12.1, under drought stress. Also, qPCR analysis conducted on
Jasmonic acid mutants revealed OsSTPK to be downregulated in wild type, reconfirming JA to be a
negative regulator of cell cycle progression. Our results suggest that OsSTPK12.1, being a LAMMER
kinase, must be involved in phosphorylation of SR proteins, which in turn are responsible for
alternative splicing of the pre mRNA and hence controlling global transcriptome of rice. Further
investigation of SR protein phosphorylation status by OsSTPK12.1, is envisioned to better understand
its complex regulation mechanism under stress.
Keywords: Drought, LAMMER Kinase, SR Proteins, Alternative splicing
