Full-length transcriptome integrated with RNA-seq reveals potassium deficiency stress-regulated key pathways and time-specific responsive genes in sugarcane roots
Xiaomin Feng, Qiaoying Zeng, Xinglong Chen, Miaomiao Shan, Zilin Wu, Nannan Zhang, Yonghong Huang, Jiayun Wu
Abstract
The absorption and efficient utilization of potassium directly impact the growth and sugar accumulation in sugarcane. Investigating the molecular response mechanism of sugarcane under low potassium stress is crucial for developing sugarcane varieties that efficiently utilize potassium resources. In this study, we conducted a comprehensive analysis of the root response of the potassium-efficient sugarcane variety Yuetang55 to low potassium stress at intervals of 0 h, 6 h, 12 h, 24 h, 48 h, and 72 h using RNA-Seq and PacBio full-length transcriptome sequencing. Our results revealed significant changes in the expression of multiple genes associated with ion transport, plant hormones, calcium ion signal transduction, transcription factors, and protein phosphorylation modification in sugarcane root under low potassium stress conditions. It is particularly striking to observe the significant upregulation of genes directly involved in potassium absorption and transport, such as HAK1 , HAK5 , AKT1 , KUP6 , and H + -ATPase genes. Additionally, genes related to hormone signaling pathways, including ABA, ethylene, and jasmonic acid pathways, exhibited significant expression alterations under low potassium stress. Furthermore, calcium signaling-related genes such as CPK4 , CML42 , CDPK11 , and CIPK23 were markedly induced under potassium deficiency. The overexpression transgenic experiment confirmed the pivotal regulatory role of ShCIPK23 in the root response to low potassium stress. Moreover, genes associated with sugar metabolism, such as UDP glucosyl and glucuronyl transferases, sucrose synthetase, and starch synthetase, displayed significant upregulation or downregulation under low potassium stress, indicating the involvement of glycometabolism in regulating sugarcane's response to potassium deficiency. These findings suggest that sugarcane's response to low potassium stress involves intricate molecular mechanisms, encompassing hormone-mediated signaling pathways, calcium ion signal transduction pathways, and sugar metabolism. • ShCIPK23 improved tolerance to low potassium stress in sugarcane. • The CBL1/CBL9-CIPK23-AKT1/HAK5 signaling pathway may be evolutionarily conserved in plants' response to low potassium stress, and this pathway plays a crucial role in enhancing potassium uptake. • The response to low potassium stress involves intricate molecular mechanisms, encompassing hormone-mediated signaling pathways, calcium ion signal transduction pathways, and sugar metabolism in sugarcane.