Objective   Genomes and expressions under stresses of the RLCK VI family genes in Gossypium barbadense were determined to study the regulatory mechanisms of the growth, development, and stress resistance of cotton plants.

  Method   Based on the latest released data on G. barbadense genome, bioinformatics of GbRLCK VI was analyzed to understand the associated physiochemical properties, sequence characteristics, gene replication, phylogenetic evolution, and expression.

  Result   Thirty-nine RLCK VI were identified in G. barbadense which were clustered into two categories of 22 in Group A and 17 in Group B. Both groups contained a kinase domain distributed in 16 chromosomes with most of them located in plasma membrane. The gene family had undergone chromosome fragment duplication events during evolution. Since all Ka/Ks of the gene pairs were less than 1, strict purification and selection might have taken place in the process. The expressions of GbRLCK VI as shown by the transcriptome analysis varied in 10 different tissues with 11 predominantly expressed in the floral organs, while 9 in the roots, stems, and leaves. Under different stresses, 8 genes were significantly expressed by the imposed drought, salt, and verticillium wilt, and 4 only by verticillium wilt. On 4 selected genes, i.e., GB_ A12G0061, GB_ A11G2234, GB_ D01G2010, and GB_ D03G0730, qRT-PCR showed their expressions under drought, salt, or verticillium wilt stress to agree with what the transcriptome data did. Their involvement in the stress response of the cotton plant was confirmed.

  Conclusion   The genome, structure, and phylogenetic characteristics of GbRLCK VI family in G. barbadense were determined. Their roles in the growth, development, and stress responses of the cotton plant were clarified.