GhKT2: a novel K+ transporter gene in cotton (Gossypium hirsutum)

摘要

Potassium is an essential nutrient for plant growth and productivity of crops.K+ transporters are important for K+ uptake and transport in plants.However,information on the function of K+ transporters and K+ channels in cotton is limited.The KT/KUP/HAK protein family is essential for a variety of physiological processes in plants,including nutrient acquisition and regulation of development.This study,identified a K+ transporter gene,GhKT2,expressed in the roots of cotton (Gossypium hirsutum) cv.Liaomianl7.The deduced transcript of GhKT2 is highly homologous to Cluster Ⅱ of KUP/HAK/ KT K+ transporters and is predicted to contain 11 transmembrane domains.GhKT2 has been localized to the plasma membrane,and its transcripts were detected in roots,stems,leaves and shoot apices of cotton seedlings.Consistently,b-glucuronidase (GUS) expression driven by the GhKT2 promoter could be detected in roots,mesophyll cells,and leaf veins in transgenic Arabidopsis.In addition,the expression of GhKT2 was induced by low K+ stress in cotton roots and pGhKT2∷GUS-transgenic Arabidopsis seedlings.The GhKT2-overexpression Arabidopsis lines plants were larger and showed greater K+ accumulation than the wild type (WT) regardless of K+ concentration supplied.The net K+ influx rate,measured by the noninvasive micro-test technique,in root meristem zone of GhKT2-transgenic Arabidopsis lines was significantly greater than that of WT.Taken together,this evidence indicates that GhKT2 may participate in K+ acquisition from low or high external K+,as well as K+ transport and distribution in plants.