Genome-Wide Identification and Characterization of SAC Domain-Containing Protein Family in Cotton

Background: Phosphoinositides(PIs) are important regulators of a diverse range of cellular functions. The Suppressor of Actin (SAC) domain-containing proteins are a class of phosphoinositide phosphatase involved in the synthesis of PIs. Though the cellular functions of SAC domain-containing proteins have been characterized in yeast, information of SAC genes in cotton is largely undefined. Results: : In the present study, 12,12and24 putative SAC genes were identified in the G. ramondii, G. arboreum and G. hirsutum respectively . Detailed gene information, including genomic organization, structural feature, conserved domain and phylogenetic relationship of the genes were systematically characterized. All SAC family members in cotton were divided into three clades, Group I, Group II and Group III, based on their sequence similarities and phylogenetic relationship. The SAC domains consist of seven highly conserved motifs that are believed to be important for the phosphoinositide phosphatase activities from yeast to animal. Expression analysis of GhSAC from Group II and Group III shared similar moderate pattern in different tissues and insensitive to different abiotic stresses. Different members in Group I showed different expressional profiles. Four genes ( GhSAC2.1A/GhSAC2.1D and GhSAC4.2A/GhSAC4.2D ) from Group I predominantly expressed in anther, pistil and petal. The results suggested the functional divergence among different groups and members of SAC in cotton. Conclusions: : Systematical analysis of the SAC gene family in cotton provided a solid foundation for further investigation of the biological functions of SAC genes.