Genome-wide analysis of zinc finger-homeodomain (ZF-HD) transcription factors in diploid and tetraploid cotton.

ZF-HD (zinc finger-homeodomain) gene family plays important roles in plant growth, development, and various stress responses. In the present study, 49, 50, 22, and 32 ZF-HD genes were identified in Gossypium hirsutum, Gossypium barbadense, Gossypium arboretum, and Gossypium raimondii genomes, respectively. According to their phylogenetic features, the ZF-HD genes were classified into six groups. Segmental duplication, whole genome duplication, and transposable elements provides major forces for the expansion of cotton ZF-HD gene family during the divergence of Gossypium species and the divergence between monocots and dicots. The Ka/Ks ratios of the ZF-HD segmental duplication pairs were mainly distributed around 0.12, which indicated that they have experienced strong purifying selective pressure during evolution. Transcriptome analysis showed that 6 Gossypium hirsutum and 4 Gossypium barbadense ZF-HD genes were expressed in all tested tissues. Further, expression profiles under abiotic stress exhibited that the ZF-HD genes were differentially regulated in response to various stresses. Taken together, our findings provide a valuable information on the characterization of ZF-HD gene family and lay foundation for their further function investigations in cotton. [ABSTRACT FROM AUTHOR]