Genome-wide analysis of the LAZ1 gene family in Gossypium hirsutum

Background As the world’s leading fiber crop and a major oil-producing crop, cotton fiber yield and fiber quality are affected by environmental stresses, especially heat, drought and salinity. The LAZ1 (Lazarus 1) family genes are responsive to abscisic acid, drought, and salt treatments. Currently, mining and functional analyses of LAZ1 family genes in cotton have not been reported. Methods and results In this study, 20 GhLAZ1 genes, designated GhLAZ1-1 - GhLAZ1-20 , were identified in the genome of Gossypium hirsutum through the construction of an HMM model, and their molecular properties, chromosomal localization, phylogeny, gene structure, evolutionary selection pressure, promoter cis elements and gene expression under salt stress were analyzed. With the exception of GhLAZ1-17 and GhLAZ1-20 , the remaining 18 GhLAZ1 genes were unevenly localized on 13 chromosomes in G. hirsutum ; evolutionary analysis showed that these genes could be divided into three subfamilies; and evolutionary selection pressure analysis demonstrated that the GhLAZ1 genes were all under purifying selection. Many elements related to light responses, hormone responses, and abiotic stresses were predicted on the GhLAZ1 family gene promoters, and real-time quantitative PCR results showed that GhLAZ1-2 , GhLAZ1-8 , and GhLAZ1-18 were upregulated significantly in salt-treated cotton leaves. Conclusions Our results suggested that GhLAZ1 genes were involved in the salt tolerance mechanism in G. hirsutum and provided a reference for further exploring the function and molecular mechanism of LAZ1 genes.