Comparative analysis of SIMILAR to RCD ONE (SRO) family from tetraploid cotton species and their diploid progenitors depict their significance in cotton growth and development

SRO (Similar to RCD1) genes family is largely recognized for their importance in the growth, development, and in responding to environmental stresses. However, genome-wide identification and functional characterization of SRO genes from cotton species have not been reported so far.

A total of 36 SRO genes were identified from four cotton species. Phylogenetic analysis divided these genes into three groups with distinct structure. Syntenic and chromosomal distribution analysis indicated uneven distribution of GaSRO, GrSRO, GhSRO, and GbSRO genes on A2, D5 genomes, Gh-At, Gh-Dt, Gb-At, and Gb-Dt subgenomes, respectively. Gene duplication analysis revealed the presence of six duplicated gene pairs among GhSRO genes. In promoter analysis, several elements responsive to the growth, development and hormones were found in GhSRO genes, implying gene induction during cotton growth and development. Several miRNAs responsive to plant growth and abiotic stress were predicted to target 12 GhSRO genes. Organ-specific expression profiling demonstrated the roles of GhSRO genes in one or more tissues. In addition, specific expression pattern of some GhSRO genes during ovule development depicted their involvement in these developmental processes.

The data presented in this report laid a foundation for understanding the classification and functions of SRO genes in cotton.