Genome-wide characterization of trichome birefringence-like genes provides insights into fiber yield improvement.

Cotton is an important fiber crop. The cotton fiber is an extremely long trichome that develops from the epidermis of an ovule. The trichome is a general and multi-function plant organ, and () genes are related to trichome development. At the genome-wide scale, we identified in four cotton species, comprising two cultivated tetraploids ( and ) and two ancestral diploids ( and ). Phylogenetic analysis showed that the genes clustered into six groups. We focused on in group IV because it was located in a lint percentage-related quantitative trait locus. In addition, we used transcriptome profiling to characterize the role of in group IV in fiber development. The overexpression of in resulted in more trichomes on the stems, thereby confirming its function in fiber development. Moreover, the potential interaction network was constructed based on the co-expression network, and it was found that may interact with several genes to regulate fiber development. These findings expand our knowledge of family members and provide new insights for cotton molecular breeding.