AUTHOR=Lim Junsub , Lim Chae Woo , Lee Sung Chul 

TITLE=Pepper Novel Serine-Threonine Kinase CaDIK1 Regulates Drought Tolerance via Modulating ABA Sensitivity

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.01133

DOI=10.3389/fpls.2020.01133

ISSN=1664-462X

ABSTRACT=<p>Adaptation to drought stress is essential for plant growth and development. Plants often adapt to water deficit conditions by activating the ABA signaling. Here, we report that the pepper <italic>CaDIK1</italic> (<italic><underline>C</underline>apsicum <underline>a</underline>nnuum</italic><underline>D</underline>rought <underline>I</underline>nduced <underline>K</underline>inase 1) gene is essential for plant tolerance to drought stress. <italic>CaDIK1</italic> contains a serine-threonine kinase domain, which plays a role for attachment of phosphate to the target protein. The expression levels of <italic>CaDIK1</italic> are upregulated in pepper leaves by ABA, drought, NaCl and H<sub>2</sub>O<sub>2</sub> treatments suggesting its role in abiotic stress response. We used <italic>CaDIK1</italic>-silenced pepper and <italic>CaDIK1-</italic>overexpressing (OX) transgenic Arabidopsis plants to evaluate their responses to ABA and drought. <italic>CaDIK1-</italic>silenced pepper plants conferred a reduced ABA sensitivity and drought hypersensitivity, which was accompanied by high levels of transpirational water loss. <italic>CaDIK1-</italic>OX plants displayed opposite phenotypes to <italic>CaDIK1</italic>-silenced peppers. In contrast, substitution of Lys350 to Asn in the kinase domain of CaDIK1 did not lead to alteration of drought sensitivity. Collectively, these data indicate that <italic>CaDIK1</italic> is a positive regulator of the ABA-mediated drought-stress tolerance.</p>