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.

中文翻译：

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来自陆地棉 (Gossypium hirsutum L.) 的活化 C 激酶 1 (RACK1) 基因受体的功能表征

活化的 C 激酶 1 (RACK1) 受体是一种保守的支架蛋白，可与多种蛋白质相互作用并参与多种细胞活动。先前的高通量转录组和蛋白质组研究均发现 RACK1 基因/蛋白质在棉花中差异表达，然而，RACK1 在这种重要的纤维生产植物中的详细功能仍不清楚。在目前的研究中，我们发现 GhRACK1 优先在快速生长的组织中表达，如棉花纤维和胚珠。通过病毒诱导的基因沉默 (VIGS) 下调棉花植株 GhRACK1 的表达和拟南芥中 GhRACK1 的异位表达均表明 GhRACK1 表达水平与植物生长速率呈正相关。生理指标（蛋白质和可溶性糖含量）进一步表明 GhRACK1 表达的下调可抑制棉花中蛋白质合成和光同化物积累，而 GhRACK1 的异位表达在拟南芥中表现出相反的作用。这些数据共同表明 GhRACK1 可能在调节棉花植株的生长发育中发挥重要作用。