Identification of Shaker Potassium Channel Family Members in Gossypium hirsutum L. and Characterization of GhKAT1aD

Abstract

K+ channels of the Shaker family have been shown to play crucial roles in K+ uptake and transport. Cotton (Gossypium hirsutum) is an important cash crop. In this study, the 24 Shaker family genes were identified in cotton. Phylogenetic analysis suggests that they were assigned to five clusters. Additionally, their chromosomal location, conserved motifs and gene structure were analyzed. The promoter of cotton Shaker K+ channel genes comprises drought-, low-temperature-, phytohormone-response elements, etc. As indicated by qRT-PCR (quantitative real-time PCR), cotton Shaker K+ channel genes responded to low K+ and NaCl, and especially dehydration stress, at the transcript level. Moreover, one of the Shaker K+ channel genes, GhKAT1aD, was characterized. This gene is localized in the plasma membrane and is predicted to contain six transmembrane segments. It restored the growth of the yeast mutant strain defective in K+ uptake, and silencing GhKAT1a via VIGS (virus-induced gene silencing) resulted in more severe symptoms of K+ deficiency in cotton leaves as well as a lower net K+ uptake rate. The results of this study showed the overall picture of the cotton Shaker K+ channel family regarding bioinformatics as well as the function of one of its members, which provide clues for future investigations of cotton K+ transport and molecular insights for breeding K+-efficient cotton varieties.