Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, China.
College of Life Science, Hubei Engineering University, Xiaogan 432100, China.
Int J Mol Sci. 2020 Nov 23;21(22):8857. doi: 10.3390/ijms21228857.
Potassium (K) plays a crucial role in multiple physiological and developmental processes in plants. Its deficiency is a common abiotic stress that inhibits plant growth and reduces crop productivity. A better understanding of the mechanisms involved in plant responses to low K could help to improve the efficiency of K use in plants. However, such responses remain poorly characterized in fruit tree species such as pears ( sp). We analyzed the physiological and transcriptome responses of a commonly used pear rootstock, , to K-deficiency stress (0 mM). Potassium deprivation resulted in apparent changes in root morphology, with short-term low-K stress resulting in rapidly enhanced root growth. Transcriptome analyses indicated that the root transcriptome was coordinately altered within 6 h after K deprivation, a process that continued until 15 d after treatment. Potassium deprivation resulted in the enhanced expression (up to 5-fold) of a putative high-affinity K transporter, (), suggesting the up-regulation of mechanisms associated with K acquisition. The enhanced root growth in response to K-deficiency stress was associated with a rapid and sustained decrease in the expression of a transcription factor, , potentially involved in mediating auxin responses, and the increased expression of multiple genes associated with regulating root growth. The concentrations of several phytohormones including indoleacetic acid (IAA), ABA, ETH, gibberellin (GA), and jasmonic acid (JA) were higher in response to K deprivation. Furthermore, genes coding for enzymes associated with carbon metabolism such as and displayed greatly enhanced expression in the roots under K deprivation, presumably indicating enhanced metabolism to meet the increased energy demands for growth and K acquisition. Together, these data suggest that K deprivation in results in the rapid re-programming of the transcriptome to enhance root growth and K acquisition. These data provide key insights into the molecular basis for understanding low-K-tolerance mechanisms in pears and in other related fruit trees and identifying potential candidates that warrant further analyses.
钾（K）在植物的多种生理和发育过程中起着至关重要的作用。其缺乏是一种常见的非生物胁迫，会抑制植物生长并降低作物产量。更好地理解植物对低钾的响应机制有助于提高植物对钾的利用效率。然而，在梨树等果树物种中，这些响应仍然特征描述不足。我们分析了常用的梨树砧木 对低钾胁迫（0 mM）的生理和转录组响应。钾缺乏导致根形态明显变化，短期低钾胁迫导致根生长迅速增强。转录组分析表明，钾剥夺后 6 小时内根转录组发生协同改变，这一过程持续到处理后 15 天。钾缺乏导致假定的高亲和力钾转运体 （）的表达增强（高达 5 倍），表明与钾获取相关的机制上调。低钾胁迫下根生长的增强与转录因子 的表达迅速且持续下降有关， 可能参与介导生长素响应，以及与调节根生长相关的多个基因的表达增加。几种植物激素包括吲哚乙酸（IAA）、ABA、ETH、赤霉素（GA）和茉莉酸（JA）的浓度对低钾胁迫有响应。此外，编码与碳代谢相关的酶的基因，如 和 ，在低钾胁迫下在根中表现出极大的增强表达，可能表明增强代谢以满足生长和钾获取增加的能量需求。综上所述，这些数据表明， 中的钾缺乏导致转录组的快速重新编程，以增强根生长和钾获取。这些数据为理解梨树和其他相关果树的低钾耐受性机制以及鉴定值得进一步分析的潜在候选基因提供了关键见解。
