The Gene Family in Cotton: Genome-Wide Characterization and Bioinformatics Analysis.

Hexokinase (HXK) is involved in hexose phosphorylation, sugar sensing, and signal transduction, all of which regulate plant growth and adaptation to stresses. L. is one of the most important fiber crops in the world, however, little is known about the gene family in L. We identified 17 from the allotetraploid L. genome (AADD). (DD) and (AA) are the diploid progenitors of L. and contributed equally to the At_genome and Dt_genome genes. The chromosomal locations and exon-intron structures of genes among cotton species are conservative. Phylogenetic analysis grouped the HXK proteins into four and three groups based on whether they were monocotyledons and dicotyledons, respectively. Duplication event analysis demonstrated that HXKs in L. primarily originated from segmental duplication, which prior to diploid hybridization. Experiments of qRT-PCR, transcriptome and promoter -elements demonstrated that promoters have auxin and GA responsive elements that are highly expressed in the fiber initiation and elongation stages, while the promoters contain ABA-, MeJA-, and SA-responsive elements that are highly expressed during the synthesis of the secondary cell wall. We performed a comprehensive analysis of the gene family is a vital fiber crop, which lays the foundation for future studies assessing its role in fiber development.