Characters and structures of the nucleobase-ascorbate transporters(NAT)family genes in Gossypium hirsutum and their roles in responding to salt and drought stresses

Background: Nucleobase-ascorbate transporters(NAT), synonymously called nucleobase-cation symporter 2(NCS2) proteins, were earlier reported to be involved in plant growth, development and resistance to stress. Previous studies concluded that s a polymorphic SNP associated with NAT12 was significant di erent between salt-tolerant and salt-sensitive materials of upland cotton. In current study, a comprehensive analysis of NAT family genes was conducted for the first time in cotton.Results: In this study, we discovered 32, 32, 18, and 16 NAT genes in Gossypium hirsutum, G. barbadense, G. raimondii and G. arboreum, respectively, which were classified into four groups(groups I–IV) based on the multiple sequence analysis. These GhNAT genes were unevenly distributed on At and Dt sub-genome in G. hirsutum. Most GhNAT members in the same group had similar gene structure characteristics and motif composition. The collinearity analysis revealed segmental duplication as well as tandem duplication contributing to the expansion of the GhNATs. The analysis of cis-acting regulatory elements of GhNATs showed that the function of GhNAT genes in cotton might be related to plant hormone and stress response. Under di erent conditions, the expression levels further suggested the GhNAT family genes were associated with plant response to various abiotic stresses. GhNAT12 was detected in the plasma membrane. And it was validated that the GhNAT12 gene played an important role in regulating cotton resistance to salt and drought stress through the virus-induced gene silencing(VIGS) analysis.Conclusions: A comprehensive analysis of NAT gene family was performed in cotton, including phylogenetic analysis, chromosomal location, collinearity analysis, motifs, gene structure and so on. Our results will further broaden the insight into the evolution and potential functions of NAT genes in cotton. Current findings could make significant contribution towards screening more candidate genes related to biotic and abiotic resistance for the improvement in cotton.