Genome-Wide Identification and Analyses of Drought/Salt-Responsive Cytochrome <i>P450</i> Genes in <i>Medicago truncatula</i>

• Main Authors: Yaying Xia, Junfeng Yang, Lin Ma, Su Yan, Yongzhen Pang
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: International Journal of Molecular Sciences
• Subjects: cytochrome P450 monooxygenase; <i>M. truncatula</i>; expression profile; co-expression analysis; salt stress; drought stress
• Online Access: https://www.mdpi.com/1422-0067/22/18/9957

Cytochrome P450 monooxygenases (P450s) catalyze a great number of biochemical reactions and play vital roles in plant growth, development and secondary metabolism. As yet, the genome-scale investigation on <i>P450s</i> is still lacking in the model legume <i>Medicago truncatula</i>. In particular, whether and how many <i>MtP450s</i> are involved in drought and salt stresses for <i>Medicago</i> growth, development and yield remain unclear. In this study, a total of 346 <i>MtP450</i> genes were identified and classified into 10 clans containing 48 families. Among them, sixty-one <i>MtP450</i> genes pairs are tandem duplication events and 10 <i>MtP450</i> genes are segmental duplication events. <i>MtP450</i> genes within one family exhibit high conservation and specificity in intron–exon structure. Meanwhile, many <i>Mt450</i> genes displayed tissue-specific expression pattern in various tissues. Specifically, the expression pattern of 204 <i>Mt450</i> genes under drought/NaCl treatments were analyzed by using the weighted correlation network analysis (WGCNA). Among them, eight genes (<i>CYP72A59v1</i>, <i>CYP74B4</i>, <i>CYP71AU56</i>, <i>CYP81E9</i>, <i>CYP71A31</i>, <i>CYP704G6</i>, <i>CYP76Y14</i>, and <i>CYP78A126</i>), and six genes (<i>CYP83D3</i>, <i>CYP76F70</i>, <i>CYP72A66</i>, <i>CYP76E1</i>, <i>CYP74C12</i>, and <i>CYP94A52</i>) were found to be hub genes under drought/NaCl treatments, respectively. The expression levels of these selected hub genes could be induced, respectively, by drought/NaCl treatments, as validated by qPCR analyses, and most of these genes are involved in the secondary metabolism and fatty acid pathways. The genome-wide identification and co-expression analyses of <i>M. truncatula</i><i>P450</i> superfamily genes established a gene atlas for a deep and systematic investigation of <i>P450</i> genes in <i>M. truncatula</i>, and the selected drought-/salt-responsive genes could be utilized for further functional characterization and molecular breeding for resistance in legume crops.