Premium
The role of calcium in ABA‐induced gene expression and stomatal movements
Author(s) -
Webb Alex A. R.,
Larman Mark G.,
Montgomery Lucy T.,
Taylor Jane E.,
Hetherington Alistair M.
Publication year - 2001
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.2001.01032.x
Subject(s) - guard cell , abscisic acid , turgor pressure , microbiology and biotechnology , second messenger system , calcium signaling , signal transduction , signalling , biology , chemistry , biochemistry , botany , gene
Summary There is much interest in the transduction pathways by which abscisic acid (ABA) regulates stomatal movements (ABA‐turgor signalling) and by which this phytohormone regulates the pattern of gene expression in plant cells (ABA‐nuclear signalling). A number of second messengers have been identified in both the ABA‐turgor and ABA‐nuclear signalling pathways. A major challenge is to understand the architecture of ABA‐signalling pathways and to determine how the ABA signal is coupled to the appropriate response. We have investigated whether separate Ca 2+ ‐dependent and ‐independent ABA‐signalling pathways are present in guard cells. Our data suggest that increases in [Ca 2+ ] i are a common component of the guard cell ABA‐turgor and ABA‐nuclear signalling pathways. The effects of Ca 2+ antagonists on ABA‐induced stomatal closure and the ABA‐responsive CDeT6‐19 gene promoter suggest that Ca 2+ is involved in both ABA‐turgor signalling and ABA‐nuclear signalling in guard cells. However, the sensitivity of these pathways to alterations in the external calcium concentration differ, suggesting that the ABA‐nuclear and ABA‐turgor signalling pathways are not completely convergent. Our data suggest that whilst Ca 2+ ‐independent signalling elements are present in the guard cell, they do not form a completely separate Ca 2+ ‐independent ABA‐signalling pathway.