Genome-wide identification of GDPD gene family in foxtail millet (Setaria italica L.) and functional characterization of SiGDPD14 under low phosphorus stress

Glycerophosphodiester phosphodiesterase (GDPD) catalyzes the hydrolysis of glycerophosphodiesters into sn-glycerol-3-phosphate (G-3-P) and corresponding alcohols, which is integral to various physiological processes in plants. However, our comprehension of the <i>GDPD</i> gene family in foxtail millet (<i>Setaria italica</i> L.) remains limited and unclear. This study aimed to identify and predict the function of <i>GDPD</i> gene family members in foxtail millet through a comprehensive genome-wide analysis.14 <i>SiGDPD</i> genes were identified in the foxtail millet genome. Phylogenetic analysis categorized <i>SiGDPD</i> proteins into five groups. Promoter regions of <i>SiGDPD</i> genes contained multiple <i>cis</i>-acting elements related to light response, hormone regulation, and stress response. Phylogenetic and collinearity analyses demonstrated conservation of GDPD proteins among foxtail millet, sorghum, rice, and maize, with the <i>SiGDPD</i> gene family undergoing purifying selection during evolution.Tissue differential expression analysis revealed distinct expression patterns of <i>SiGDPD</i> genes across various tissues, showing spatiotemporal expression characteristics. Under low phosphorus stress, the expression levels of <i>SiGDPD3</i> and <i>SiGDPD14</i> significantly increased, while <i>SiGDPD1</i>, <i>SiGDPD5</i>, <i>SiGDPD6</i>, and <i>SiGDPD11</i> showed significant decreases.To identify the function of <i>SiGDPD14</i>, an over-expressed transgenic <i>Arabidopsis</i> was generated. The results showed that transgenic <i>Arabidopsis thaliana</i> plants over-expressing <i>SiGDPD14</i> exhibited enhanced tolerance to low phosphorus stress.Taken together, the results of this study provide valuable information for further studies on candidate <i>SiGDPD</i> genes involved in the phosphate deficiency response in foxtail millet.