AUTHOR=Lim Chae Woo , Lee Sung Chul 

TITLE=ABA-Dependent and ABA-Independent Functions of RCAR5/PYL11 in Response to Cold Stress

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.587620

DOI=10.3389/fpls.2020.587620

ISSN=1664-462X

ABSTRACT=<p><italic>Arabidopsis thaliana</italic> has 14 abscisic acid (ABA) receptors—PYR1/PYLs/RCARs—which have diverse and redundant functions in ABA signaling; however, the precise role of these ABA receptors remains to be elucidated. Here, we report the functional characterization of RCAR5/PYL11 in response to cold stress. Expression of <italic>RCAR5</italic> gene in dry seeds and leaves was ABA-dependent and ABA-independent, respectively. Under cold stress conditions, seed germination was negatively affected by the level of <italic>RCAR5</italic> expression, which was dependent on ABA and was regulated by HAB1, OST1, and ABI5—downstream components of RCAR5 in ABA signaling. Leaves of <italic>RCAR5</italic>-overexpressing plants showed enhanced stomatal closure—independent of ABA—and high expression levels of cold, dehydration, and/or ABA-responsive genes compared to those of wild-type; these traits conferred enhanced freezing tolerance. Our data suggest that RCAR5 functions in response to cold stress by delaying seed germination and inducing rapid stomatal closure <italic>via</italic> ABA-dependent and ABA-independent pathways, respectively.</p>