AUTHOR=Yu Tai-Fei , Zhao Wan-Ying , Fu Jin-Dong , Liu Yong-Wei , Chen Ming , Zhou Yong-Bin , Ma You-Zhi , Xu Zhao-Shi , Xi Ya-Jun 

TITLE=Genome-Wide Analysis of CDPK Family in Foxtail Millet and Determination of SiCDPK24 Functions in Drought Stress

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00651

DOI=10.3389/fpls.2018.00651

ISSN=1664-462X

ABSTRACT=<p>Plant calcium-dependent protein kinases (CDPKs) were reported to play important roles in plant resistance to abiotic stress. Foxtail millet cultivation “H138” was used for RNA-seq analysis. The data from drought-induced <italic>de novo</italic> transcriptomic sequences of foxtail millet showed that CDPKs were up- or down-regulated by drought to different degrees. In this study, 29 foxtail millet CDPKs were classified into four subgroups. These genes were unevenly distributed on nine foxtail millet chromosomes, and chromosomes 2, 3, and 9 contained the most SiCDPK members. Analysis of putative <italic>cis</italic>-acting elements showed that most foxtail millet CDPK genes contained the ABRE, LTR, HSE, MYB, MYC, DRE, CGTCA-motif, and TGACG-motif <italic>cis</italic>-acting elements, which could be activated by abiotic stresses. Real-time PCR analysis indicated that 29 SiCDPK genes experienced different degrees of induction under drought and ABA stresses. <italic>SiCDPK24</italic> had the highest expression levels at 6 and 12 h of drought treatment and was chosen for further analysis. SiCDPK24 localized to the cell membrane and the nucleus of <italic>Arabidopsis</italic> mesophyll protoplasts. Western blot analysis showed that SiCDPK24 protein had autophosphorylation activity. Overexpression of <italic>SiCDPK24</italic> in <italic>Arabidopsis</italic> enhanced drought resistance and improved the survival rate under drought stress. It also activated the expressions of nine stress-related genes, namely <italic>RD29A</italic>, <italic>RD29B</italic>, <italic>RD22</italic>, <italic>KIN1</italic>, <italic>COR15</italic>, <italic>COR47</italic>, <italic>LEA14</italic>, <italic>CBF3/DREB1A</italic>, and <italic>DREB2A</italic>. These genes are involved in resistance to abiotic stresses in <italic>Arabidopsis</italic>. These results indicate that foxtail millet CDPK genes play important roles in resisting drought stress.</p>