Genome-Wide Identification and Analysis of P-Type Plasma Membrane H⁺-ATPase Sub-Gene Family in Sunflower and the Role of <i>HHA4</i> and <i>HHA11</i> in the Development of Salt Stress Resistance

• Main Authors: Zongchang Xu, Prince Marowa, Han Liu, Haina Du, Chengsheng Zhang, Yiqiang Li
• Format: Article
• Language: English
• Published: MDPI AG 2020-03-01
• Series: Genes
• Subjects: P-type plasma membrane ATPase; salt stress; gene expression; bioinformatics analysis; sunflower
• Online Access: https://www.mdpi.com/2073-4425/11/4/361
• ISSN: 2073-4425

The P-type plasma membrane (PM) H⁺-ATPase plays a major role during the growth and development of a plant. It is also involved in plant resistance to a variety of biotic and abiotic factors, including salt stress. The PM H⁺-ATPase gene family has been well characterized in <i>Arabidopsis</i> and other crop plants such as rice, cucumber, and potato; however, the same cannot be said in sunflower (<i>Helianthus annuus</i>). In this study, a total of thirteen PM H⁺-ATPase genes were screened from the recently released sunflower genome database with a comprehensive genome-wide analysis. According to a systematic phylogenetic classification with a previously reported species, the sunflower PM H⁺-ATPase genes (<i>HHAs</i>) were divided into four sub-clusters (I, II, IV, and V). In addition, systematic bioinformatics analyses such as gene structure analysis, chromosome location analysis, subcellular localization predication, conserved motifs, and <i>Cis</i>-acting elements of promoter identification were also done. Semi-quantitative PCR analysis data of <i>HHAs</i> in different sunflower tissues revealed the specificity of gene spatiotemporal expression and sub-cluster grouping. Those belonging to sub-cluster I and II exhibited wide expression in almost all of the tissues studied while sub-cluster IV and V seldom showed expression. In addition, the expression of <i>HHA4</i>, <i>HHA11,</i> and <i>HHA13</i> was shown to be induced by salt stress. The transgenic plants overexpressing <i>HHA4</i> and <i>HHA11</i> showed higher salinity tolerance compared with wild-type plants. Further analysis showed that the Na⁺ content of transgenic <i>Arabidopsis</i> plants decreased under salt stress, which indicates that PM H⁺ ATPase participates in the physiological process of Na⁺ efflux, resulting in salt resistance of the plants. This study is the first to identify and analyze the sunflower PM H⁺ ATPase gene family. It does not only lay foundation for future research but also demonstrates the role played by <i>HHAs</i> in salt stress tolerance.