外源钙对茶树（(L.) Kuntze）抗旱响应的影响。

Effects of exogenous calcium on the drought response of the tea plant ( (L.) Kuntze).

机构信息

Federal Research Centre the Subtropical Scientific Centre of the Russian Academy of Sciences, Sochi, Russia.

Agrarian and Technological Institute, Peoples' Friendship University of Russia, Moscow, Russia.

出版信息

PeerJ. 2022 Aug 29;10:e13997. doi: 10.7717/peerj.13997. eCollection 2022.

DOI:10.7717/peerj.13997

PMID:36061747

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9435517/

Abstract

BACKGROUND

Drought is one of the major factors reducing the yield of many crops worldwide, including the tea crop ( (L.) Kuntze). Calcium participates in most of cellular signaling processes, and its important role in stress detection and triggering a response has been shown in many crops. The aim of this study was to evaluate possible effects of calcium on the tea plant response to drought.

METHODS

Experiments were conducted using 3-year-old potted tea plants of the best local cultivar Kolkhida. Application of ammonium nitrate (control treatment) or calcium nitrate (Ca treatment) to the soil was performed before drought induction. Next, a 7-day drought was induced in both groups of plants. The following physiological parameters were measured: relative electrical conductivity, pH of cell sap, and concentrations of cations, sugars, and amino acids. In addition, relative expression levels of 40 stress-related and crop quality-related genes were analyzed.

RESULTS

Under drought stress, leaf electrolyte leakage differed significantly, indicating greater damage to cell membranes in control plants than in Ca-treated plants. Calcium application resulted in greater pH of cell sap; higher accumulation of tyrosine, methionine, and valine; and a greater Mg content as compared to control plants. Drought stress downregulated most of the quality-related genes in both groups of tea plants. By contrast, significant upregulation of some genes was observed, namely , , , , , , , , , , , , , and . Among them, three genes (, , and ) showed 2-3 times greater expression in Ca-treated plants than in control plants. Based on these results, it can be speculated that calcium affects galactinol biosynthesis and participates in the regulation of stomatal aperture not only through activation of abscisic-acid signaling but also through jasmonic-acid pathway activation. These findings clarify calcium-mediated mechanisms of drought defense in tree crops. Thus, calcium improves the drought response in the tea tree.

摘要

背景

干旱是降低全球许多作物包括茶树（(L.) Kuntze）产量的主要因素之一。钙参与大多数细胞信号转导过程，其在应激检测和触发响应中的重要作用已在许多作物中得到证实。本研究旨在评估钙对茶树对干旱的反应的可能影响。

方法

使用 3 年生的当地最佳品种科赫希达（Kolkhida）盆栽茶树进行实验。在诱导干旱之前，将硝酸铵（对照处理）或硝酸钙（Ca 处理）施用于土壤中。然后，对两组植物进行为期 7 天的干旱胁迫。测量了以下生理参数：相对电导率、细胞汁液 pH 值以及阳离子、糖和氨基酸的浓度。此外，还分析了 40 个与应激和作物品质相关的基因的相对表达水平。

结果

在干旱胁迫下，叶片电解质渗透率有显著差异，表明对照植株的细胞膜损伤比 Ca 处理植株严重。钙处理导致细胞汁液 pH 值升高；酪氨酸、甲硫氨酸和缬氨酸积累增加；与对照植株相比，Mg 含量增加。干旱胁迫下调了两组茶树的大多数与品质相关的基因。相比之下，一些基因的表达显著上调，即、、、、、、、、、、、、、和。其中，三个基因（、和）在 Ca 处理植株中的表达量比对照植株高 2-3 倍。基于这些结果，可以推测钙通过激活脱落酸信号而不是仅通过茉莉酸途径激活来影响半乳糖醇的生物合成并参与气孔开度的调节。这些发现阐明了钙介导的树木作物抗旱防御机制。因此，钙改善了茶树的抗旱性。