Genome-Wide Detection of SPX Family and Profiling of in Regulating Low-Phosphate Stress in Tea-Oil .

a member of the family Theaceae, is a phosphorus (P) tolerator native to southern China. The SPX gene family critically regulates plant growth and development and maintains phosphate (Pi) homeostasis. However, the involvement of genes in Pi signaling in Tea-Oil remains unknown. In this work, 20 genes were identified and categorized into four subgroups. Conserved domains, motifs, gene structure, chromosomal location and gene duplication events were also investigated in the SPX gene family. Defense and stress responsiveness cis-elements were identified in the gene promoters, which participated in low-Pi stress responses. Based on transcriptome data and qRT-PCR results, nine genes had similar expression patterns and eight genes (except ) were up-regulated at 30 days after exposure to low-Pi stress. was selected as a key candidate gene by WGCNA analysis. CoSPX-MFS3 was a tonoplast protein. Overexpression of in promoted the accumulation of total P content and decreased the anthocyanin content. Overexpression of could enhance low-Pi tolerance by increased biomass and organic acid contents in transgenic lines. Furthermore, the expression patterns of seven phosphate starvation genes were higher in transgenic than those in the wild type. These results highlight novel physiological roles of the family genes in under low-Pi stress, and lays the foundation for a deeper knowledge of the response mechanism of to low-Pi stress.