Molecular Characterization of the Acyl-CoA-Binding Protein Genes Reveals Their Significant Roles in Oil Accumulation and Abiotic Stress Response in Cotton

Members of the acyl-CoA-binding protein (ACBP) gene family play vital roles in diverse processes related to lipid metabolism, growth and development, and environmental response. Plant ACBP genes have been well-studied in a variety of species including Arabidopsis, soybean, rice and maize. However, the identification and functions of ACBP genes in cotton remain to be elucidated. In this study, a total of 11 GaACBP, 12 GrACBP, 20 GbACBP, and 19 GhACBP genes were identified in the genomes of Gossypium arboreum, Gossypium raimondii, Gossypium babardense, and Gossypium hirsutum, respectively, and grouped into four clades. Forty-nine duplicated gene pairs were identified in Gossypium ACBP genes, and almost all of which have undergone purifying selection during the long evolutionary process. In addition, expression analyses showed that most of the GhACBP genes were highly expressed in the developing embryos. Furthermore, GhACBP1 and GhACBP2 were induced by salt and drought stress based on a real-time quantitative PCR (RT-qPCR) assay, indicating that these genes may play an important role in salt- and drought-stress tolerance. This study will provide a basic resource for further functional analysis of the ACBP gene family in cotton.