National Engineering Research Center of Tree breeding and Ecological restoration, College of Biological Sciences and Technology, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, PR China.
College of Biological Sciences and Technology, Taiyuan Normal University, Jinzhong 030619, PR China.
Int J Biol Macromol. 2024 May;267(Pt 2):131256. doi: 10.1016/j.ijbiomac.2024.131256. Epub 2024 Mar 29.
Given the detrimental impact of global warming on crop production, it is particularly important to understand how plants respond and adapt to higher temperatures. Using the non-invasive micro-test technique and laser confocal microscopy, we found that the cascade process of early signals (K, HO, H, and Ca) ultimately resulted in an increase in the cytoplasmic Ca concentration when Arabidopsis was exposed to heat stress. Quantitative real-time PCR demonstrated that heat stress significantly up-regulated the expression of CAM1, CAM3 and HSFA2; however, after CAM1 and CAM3 mutation, the upregulation of HSFA2 was reduced. In addition, heat stress affected the expression of LOX3 and OPR3, which was not observed when HSFA2 was mutated. Luciferase reporter gene expression assay and electrophoretic mobility shift assay showed that HSFA2 regulated the expression of both genes. Determination of jasmonic acid (JA) content showed that JA synthesis was promoted by heat stress, but was damaged when HSFA2 and OPR3 were mutated. Finally, physiological experiments showed that JA reduced the relative electrical conductivity of leaves, enhanced chlorophyll content and relative water content, and improved the survival rate of Arabidopsis under heat stress. Together, our results reveal a new pathway for Arabidopsis to sense and transmit heat signals; HSFA2 is involved in the JA synthesis, which can act as a defensive compound improving Arabidopsis heat tolerance.
鉴于全球变暖对作物生产的不利影响，了解植物如何应对和适应更高的温度尤为重要。本研究采用非侵入性微测试技术和激光共聚焦显微镜，发现拟南芥受到热胁迫时，早期信号（K、HO、H 和 Ca）的级联过程最终导致细胞质 Ca 浓度增加。实时定量 PCR 表明，热胁迫显著上调了 CAM1、CAM3 和 HSFA2 的表达；然而，在 CAM1 和 CAM3 突变后，HSFA2 的上调减少。此外，热胁迫影响 LOX3 和 OPR3 的表达，而当 HSFA2 突变时则观察不到这种影响。荧光素酶报告基因表达分析和电泳迁移率变动分析表明，HSFA2 调节这两个基因的表达。茉莉酸（JA）含量的测定表明，JA 的合成受到热胁迫的促进，但当 HSFA2 和 OPR3 突变时受到破坏。最后，生理实验表明，JA 降低了叶片的相对电导率，提高了叶绿素含量和相对含水量，提高了拟南芥在热胁迫下的存活率。综上所述，我们的研究结果揭示了拟南芥感知和传递热信号的新途径；HSFA2 参与了 JA 的合成，可作为一种防御化合物提高拟南芥的耐热性。
