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Heat shock‐induced biphasic Ca 2+ signature and OsCaM1‐1 nuclear localization mediate downstream signalling in acquisition of thermotolerance in rice ( Oryza sativa L.)
Author(s) -
WU HUICHEN,
LUO DANLI,
VIGNOLS FLORENCE,
JINN TSUNGLUO
Publication year - 2012
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2012.02508.x
Subject(s) - microbiology and biotechnology , calmodulin , gene expression , epicotyl , heat shock , biology , chemistry , heat shock protein , biochemistry , gene , botany , seedling , enzyme
We investigated heat shock (HS)‐triggered Ca 2+ signalling transduced by a Ca 2+ sensor, calmodulin (CaM), linked to early transcriptome changes of HS‐responsive genes in rice. We observed a biphasic [Ca 2+ ] cyt signature in root cells that was distinct from that in epicotyl and leaf cells, which showed a monophasic response after HS. Treatment with Ca 2+ and A23187 generated an intense and sustained increase in [Ca 2+ ] cyt in response to HS. Conversely, treatment with Ca 2+ chelator, L‐type Ca 2+ channel blocker and CaM antagonist, but not intracellular Ca 2+ release inhibitor, strongly inhibited the increased [Ca 2+ ] cyt . HS combined with Ca 2+ and A23187 accelerated the expression of OsCaM1‐1 and sHSPC/N genes, which suggests that the HS‐induced apoplastic Ca 2+ influx is responsible for the [Ca 2+ ] cyt response and downstream HS signalling. In addition, the biphasic response of OsCaM1‐1 in the nucleus followed the Ca 2+ signature, which may provide the information necessary to direct HS‐related gene expression. Overexpression of OsCaM1‐1 induced the expression of Ca 2+ /HS‐related AtCBK3 , AtPP7 , AtHSF and AtHSP at a non‐inducing temperature and enhanced intrinsic thermotolerance in transgenic Arabidopsis . Therefore, HS‐triggered rapid increases in [Ca 2+ ] cyt , together with OsCaM1‐1 expression and its nuclear localization, are important in mediating downstream HS‐related gene expression for the acquisition of thermotolerance in rice.