Genome-Wide Identification and Analysis of the WNK Kinase Gene Family in Upland Cotton

With-No-Lysine (WNK) kinases are a subfamily of serine/threonine protein kinases. WNKs are involved in plant abiotic stress response and circadian rhythms. However, members of the WNK subfamily and their responses to abiotic and biotic stresses in Gossypium hirsutum have not been reported. In this study, 26 GhWNKs were identified in G. hirsutum. The gene structure, conserved motifs, and upstream open reading frames (uORFs) of GhWNKs were identified. Moreover, GhWNKs regulation is predicted to be regulated by cis-acting elements, such as ABA responsive element (ABRE), MBS, and MYC. Furthermore, transcription factors including MIKC_MADS, C2H2, TALE, bZIP, Dof, MYB, bHLH, and HD-ZIP are projected to play a regulatory role in GhWNKs. The expression patterns of GhWNKs under normal conditions and biotic and abiotic stresses were evaluated, and their expression was found to vary. The expression patterns of several GhWNKs were induced by infiltration with Verticillium dahliae, suggesting that several GhWNKs may play important roles in the response of cotton to V. dahliae. Interestingly, a homoeologous expression bias within the GhWNKs was uncovered in upland cotton. Homoeologous expression bias within GhWNKs provides a framework to assist researchers and breeders in developing strategies to improve cotton traits by manipulating individual or multiple homeologs.