AUTHOR=Chen Lijuan , Xiao Jiahui , Song Yuxiao , Li You , Liu Jun , Cai Huiren , Wang Hong-Bin , Liu Bing 

TITLE=The Zygotic Division Regulator ZAR1 Plays a Negative Role in Defense Against Botrytis cinerea in Arabidopsis

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.736560

DOI=10.3389/fpls.2021.736560

ISSN=1664-462X

ABSTRACT=<p>A phosphorylation/dephosphorylation cycle at tyrosine 428 of CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) plays an essential role in chitin triggered immunity in <italic>Arabidopsis thaliana</italic>. In this study, we used a differential peptide pull-down (PPD) assay to identify factors that could participate downstream of this cycle. We identified ZYGOTIC ARREST 1 (ZAR1) and showed that it interacts with CERK1 specifically when the tyrosine 428 (Y428) residue of CERK1 is dephosphorylated. ZAR1 was originally characterized as an integrator for calmodulin and G-protein signals to regulate zygotic division in <italic>Arabidopsis</italic>. Our current results established that ZAR1 also negatively contributed to defense against the fungus <italic>Botrytis cinerea</italic> and played a redundant role with its homolog ZAR2 in this process. The <italic>zar1-3 zar2-1</italic> double mutant exhibited stronger resistance to <italic>B. cinerea</italic> compared with <italic>zar1-3</italic> single mutant, <italic>zar2-1</italic> single mutant, and wild-type plants. Moreover, the inducible expression of numerous defense response genes upon <italic>B. cinerea</italic> infection was increased in the <italic>zar1-3zar2-1</italic> double mutant, consistent with a repressive role for ZAR proteins in the defense response. Therefore, our findings provided insight into the function of ZAR1 in multiple defenses and developmental regulation pathways.</p>