AUTHOR=Wu Zhanwei , Luo Lu , Wan Yongshan , Liu Fengzhen 

TITLE=Genome-wide characterization of the PP2C gene family in peanut (Arachis hypogaea L.) and the identification of candidate genes involved in salinity-stress response

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1093913

DOI=10.3389/fpls.2023.1093913

ISSN=1664-462X

ABSTRACT=<p>Plant protein phosphatase 2C (PP2C) play important roles in response to salt stress by influencing metabolic processes, hormone levels, growth factors, etc. Members of the PP2C family have been identified in many plant species. However, they are rarely reported in peanut. In this study, 178 <italic>PP2C</italic> genes were identified in peanut, which were unevenly distributed across the 20 chromosomes, with segmental duplication in 78 gene pairs. AhPP2Cs could be divided into 10 clades (A-J) by phylogenetic analysis. <italic>AhPP2C</italic>s had experienced segmental duplications and strong purifying selection pressure. 22 miRNAs from 14 different families were identified, targeting 57 <italic>AhPP2C</italic> genes. Gene structures and motifs analysis exhibited <italic>PP2C</italic>s in subclades AI and AII had high structural and functional similarities. Phosphorylation sites of <italic>AhPP2C45</italic>/<italic>59</italic>/<italic>134</italic>/<italic>150</italic>/<italic>35</italic>/<italic>121</italic> were predicted in motifs 2 and 4, which located within the catalytic site at the C-terminus. We discovered multiple MYB binding factors and ABA response elements in the promoter regions of the six genes (<italic>AhPP2C45</italic>/<italic>59</italic>/<italic>134</italic>/<italic>150</italic>/<italic>35</italic>/<italic>121</italic>) by <italic>cis</italic>-elements analysis. GO and KEGG enrichment analysis confirmed <italic>AhPP2C-A</italic> genes in protein binding, signal transduction, protein modification process response to abiotic stimulus through environmental information processing. Based on RNA-Seq data of 22 peanut tissues, clade A <italic>AhPP2C</italic>s showed a varying degree of tissue specificity, of which, <italic>AhPP2C35</italic> and <italic>AhPP2C121</italic> specifically expressed in seeds, while <italic>AhPP2C45</italic>/<italic>59</italic>/<italic>134</italic>/<italic>150</italic> expressed in leaves and roots. qRT-PCR indicated that <italic>AhPP2C45</italic> and <italic>AhPP2C134</italic> displayed significantly up-regulated expression in response to salt stress. These results indicated that <italic>AhPP2C45</italic> and <italic>AhPP2C134</italic> could be candidate <italic>PP2Cs</italic> conferring salt tolerance. These results provide further insights into the peanut <italic>PP2C</italic> gene family and indicate <italic>PP2Cs</italic> potentially involved in the response to salt stress, which can now be further investigated in peanut breeding efforts to obtain cultivars with improved salt tolerance.</p>