AUTHOR=Jeong Soongon , Lim Chae Woo , Lee Sung Chul 

TITLE=The Pepper MAP Kinase CaAIMK1 Positively Regulates ABA and Drought Stress Responses

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00720

DOI=10.3389/fpls.2020.00720

ISSN=1664-462X

ABSTRACT=<p>Protein phosphorylation and dephosphorylation are important mechanisms that regulate many cellular processes. Protein kinases usually function in the regulation of the stress responses by adjusting activity via phosphorylation of target proteins. Here, we isolated <italic>CaAIMK1</italic> (<italic>Capsicum annuum</italic> ABA Induced MAP Kinase 1) from the pepper leaves that had been subjected to drought stress. <italic>CaAIMK1</italic> transcripts were induced by drought, abscisic acid (ABA), high salinity, and H<sub>2</sub>O<sub>2</sub>; further, the CaAIMK1-Green fluorescent protein localized in the nucleus and cytoplasm. We performed genetic studies using <italic>CaAIMK1</italic>-silenced pepper plants and <italic>CaAIMK1-</italic>overexpressing (OX) Arabidopsis plants. <italic>CaAIMK1-</italic>silenced pepper plants showed a drought-sensitive phenotype characterized by altered ABA signaling, including low leaf temperatures, and large stomatal apertures. <italic>CaAIMK1-</italic>OX plants exhibited a contrasting drought-tolerant phenotype characterized by decreased levels of transpirational water loss and increased expression levels of Arabidopsis stress-related genes. In <italic>CaAIMK1</italic><sup>K32N</sup>-OX transgenic Arabidopsis plants, sensitivity to ABA and drought was restored. Collectively, these results demonstrate that CaAIMK1 positively regulates the drought stress responses via an ABA-dependent pathway.</p>