State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing 100193, China.
College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
Int J Mol Sci. 2021 Mar 19;22(6):3133. doi: 10.3390/ijms22063133.
To properly understand cotton responses to potassium (K) deficiency and how its shoot feedback regulates K uptake and root growth, we analyzed the changes in root transcriptome induced by low K (0.03 mM K, lasting three days) in self-grafts of a K inefficient cotton variety (CCRI41/CCRI41, scion/rootstock) and its reciprocal grafts with a K efficient variety (SCRC22/CCRI41). Compared with CCRI41/CCRI41, the SCRC22 scion enhanced the K uptake and root growth of CCRI41 rootstock. A total of 1968 and 2539 differently expressed genes (DEGs) were identified in the roots of CCRI41/CCRI41 and SCRC22/CCRI41 in response to K deficiency, respectively. The overlapped and similarly (both up- or both down-) regulated DEGs in the two grafts were considered the basic response to K deficiency in cotton roots, whereas the DEGs only found in SCRC22/CCRI41 (1954) and those oppositely (one up- and the other down-) regulated in the two grafts might be the key factors involved in the feedback regulation of K uptake and root growth. The expression level of four putative K transporter genes (three and one ) increased in both grafts under low K, which could enable plants to cope with K deficiency. In addition, two ethylene response factors (ERFs), and , both down-regulated in the roots of CCRI41/CCRI41 and SCRC22/CCRI41, may negatively regulate K uptake in cotton roots due to higher net K uptake rate in their virus-induced gene silencing (VIGS) plants. In terms of feedback regulation of K uptake and root growth, several up-regulated DEGs related to Ca binding and CIPK (CBL-interacting protein kinases), one up-regulated and several up-regulated probably play important roles. In conclusion, these results provide a deeper insight into the molecular mechanisms involved in basic response to low K stress in cotton roots and feedback regulation of K uptake, and present several low K tolerance-associated genes that need to be further identified and characterized.
为了正确理解棉花对钾（K）缺乏的响应以及其地上部反馈如何调节 K 吸收和根系生长，我们分析了低钾（0.03 mM K，持续 3 天）对自嫁接的 K 低效棉花品种（CCRI41/CCRI41，接穗/砧木）和其与 K 高效品种（SCRC22/CCRI41）的互嫁接株根转录组的变化。与 CCRI41/CCRI41 相比，SCRC22 接穗增强了 CCRI41 砧木的 K 吸收和根系生长。在低钾条件下，CCRI41/CCRI41 和 SCRC22/CCRI41 的根系分别鉴定出 1968 和 2539 个差异表达基因（DEGs）。在两个嫁接体中，重叠且相似（均上调或均下调）调节的 DEGs 被认为是棉花根系对 K 缺乏的基本响应，而仅在 SCRC22/CCRI41 中发现的 DEGs（1954 个）和在两个嫁接体中反向（一个上调，另一个下调）调节的 DEGs可能是参与 K 吸收和根系生长反馈调节的关键因素。在低钾条件下，四个假定的 K 转运体基因（三个 和一个 ）在两个嫁接体中的表达水平均升高，这可能使植物能够应对 K 缺乏。此外，在 CCRI41/CCRI41 和 SCRC22/CCRI41 的根系中均下调表达的两个乙烯反应因子（ERFs） 和 ，由于其病毒诱导基因沉默（VIGS）植株的净 K 吸收速率较高，可能负调控棉花根系的 K 吸收。就 K 吸收和根系生长的反馈调节而言，几个与 Ca 结合和 CIPK（CBL 相互作用蛋白激酶）相关的上调 DEGs、一个上调的 和几个上调的 可能发挥重要作用。总之，这些结果深入了解了棉花根系对低钾胁迫的基本响应和 K 吸收的反馈调节所涉及的分子机制，并提出了几个需要进一步鉴定和表征的低钾耐受相关基因。
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