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Light signalling mediated by phytochrome plays an important role in cold‐induced gene expression through the C‐repeat/dehydration responsive element (C/DRE) in Arabidopsis thaliana
Author(s) -
Kim HyounJoung,
Kim YunKyoung,
Park JinYoung,
Kim Jungmook
Publication year - 2002
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2002.01249.x
Subject(s) - phytochrome , phytochrome a , biology , arabidopsis , reporter gene , gene expression , arabidopsis thaliana , transgene , microbiology and biotechnology , mutant , phosphatase , gene , okadaic acid , phosphorylation , genetics , botany , red light
Summary Low temperature induces a number of genes that encode the proteins promoting tolerance to freezing, mediated by ABA‐dependent and ABA–independent pathways in plants. The cis ‐acting element called C/DRE is known to respond to low temperature independently of ABA action . To investigate the signalling and network of ABA‐independent pathways, the transgenic Arabidopsis plants were generated containing several copies of the C/DRE derived from cor15a gene with a minimal promoter fused to a GUS reporter gene. The transgenic plants containing four copies of the C/DRE ( 4C/DRE‐GUS ) showed responsiveness to cold and drought treatments and were used for characterization of cold signalling and cross‐talk. Cold‐induced GUS expression was inhibited by okadaic acid at 1 n m , indicating that protein phosphatase 2A might act as a positive regulator. Light was shown to activate cold‐ and drought‐induced GUS expression. Photo‐reversibility of the GUS mRNA by red and far‐red light with concomitant cold treatment suggests a role of phytochrome as a photoreceptor in mediating light signalling to activate the cold‐induced gene expression through the C/DRE . Furthermore, GUS expression analysis in phyA or phyB or phyAphyB mutant backgrounds showed that phytochrome B is a primary photoreceptor responsible for the activation of cold‐stress signalling in response to light. Light enhanced the induction kinetics of CBF1 , 2 , and 3 encoding the cognate transcription factors, and cor15a , in a consecutive manner compared to the dark condition in the cold, suggesting that the connection point between cold and light signalling mediated by phytochrome is at a higher step than the expression of CBF genes.