Functional characterization of a receptor for activated C kinase 1 (RACK1) gene from upland cotton (Gossypium hirsutum L.)

Abstract

Receptor for activated C kinase 1 (RACK1) is a conserved scaffold protein interacting with multiple proteins and participates in diverse cellular activities. Previous high-throughput transcriptome and proteome studies both identified RACK1 gene/protein was differentially expressed in cotton, however, the detailed function of RACK1 in this important fiber-producing plant is still unclear. In the current study, we found that GhRACK1 was preferentially expressed in fast growing tissues, such as cotton fibers and ovules. Down-regulation of GhRACK1 expression in cotton plants through virus-induced gene silencing (VIGS) and ectopic expression of GhRACK1 in Arabidopsis both revealed a positive correlation between GhRACK1 expression level and plant growth rate. Physiological index (protein and soluble sugar content) further indicated that down-regulation of GhRACK1 expression could inhibit protein synthesis and photoassimilate accumulation in cotton, whereas ectopic expression of GhRACK1 exhibited opposite effects in Arabidopsis. These data collectively suggested that GhRACK1 might play an important role in regulating the growth and development of cotton plants.