AUTHOR=Xie Wenya , Li Xinru , Wang Shiping , Yuan Meng 

TITLE=OsWRKY53 Promotes Abscisic Acid Accumulation to Accelerate Leaf Senescence and Inhibit Seed Germination by Downregulating Abscisic Acid Catabolic Genes in Rice

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.816156

DOI=10.3389/fpls.2021.816156

ISSN=1664-462X

ABSTRACT=<p>Abscisic acid (ABA) largely promotes leaf senescence and inhibits seed germination in plants. Endogenous ABA content is finely tuned by many transcription factors. In this study, we showed that <italic>OsWRKY53</italic> is a positive regulator of leaf senescence and a negative regulator of seed germination in rice. <italic>OsWRKY53</italic> expression was induced in leaves under aging, dark, and ABA treatment. The <italic>OsWRKY53</italic>-overexpressing (<italic>OsWRKY53</italic>-oe) plants showed early yellowing leaves, while the <italic>OsWRKY53</italic> (<italic>oswrky53</italic>) knockout mutants maintained green leaves than the wild type under natural, dark-induced, and ABA-induced senescence conditions. Transcriptional analysis revealed that ABA catabolic genes, namely, <italic>OsABA8ox1</italic> and <italic>OsABA8ox2</italic>, two key genes participating in ABA catabolism harboring ABA 8′-hydroxylase activity, were markedly downregulated in <italic>OsWRKY53</italic>-oe leaves. Chromatin immunoprecipitation and protoplast transient assays revealed that OsWRKY53 directly bound to the promoters of <italic>OsABA8ox1</italic> and <italic>OsABA8ox2</italic> to repress their transcription, resulting in elevated endogenous ABA contents that promoted premature leaf senescence in the <italic>OsWRKY53</italic>-oe plants. It indicates that OsWRKY53 is a positive regulator through regulating ABA accumulation to promote leaf senescence. In addition, accumulated ABA simultaneously inhibited seed germination and post-germination growth in <italic>OsWRKY53</italic>-oe plants. Taken together, OsWRKY53 suppresses the transcript of ABA catabolic genes to promote ABA accumulation to modulate ABA-induced leaf senescence and ABA-mediated inhibition of seed germination.</p>