A Wall-Associated Kinase Gene CaWAKL20 From Pepper Negatively Modulates Plant Thermotolerance by Reducing the Expression of ABA-Responsive Genes
A Wall-Associated Kinase Gene CaWAKL20 From Pepper Negatively Modulates Plant Thermotolerance by Reducing the Expression of ABA-Responsive Genes
复制标题
辣椒中的壁相关激酶基因 CaWAKL20 通过减少 ABA 响应基因的表达来负调节植物耐热性
DOI：
10.3389/fpls.2019.00591
复制
发表时间：
2019
影响因子：
5.6
通讯作者：
Lu Minghui
中科院分区：
文献类型：
--
作者：
Wang Hu;Niu Huanhuan;Liang Minmin;Zhai Yufei;Huang Wei;Ding Qin;Du Yu;Lu Minghui
由于全球变暖，热胁迫已成为作物生产的主要威胁，然而，植物高温感知的机制尚不清楚。在植物中，膜锚定受体样激酶（RLKs）将环境信号传递到细胞质中。在前期的研究中，我们从辣椒中分离到一个与细胞壁相关的类RLK-like（WAKL）基因CaWAKL 20。在此，CaWAKL 20的氨基酸序列被表征并发现由WAK/WAKL家族的保守结构域组成，包括含有GUB-WAK结合结构域和简并的EGF 2样结构域的胞外区;跨膜区;和具有STKc催化结构域的胞间区。此外，CaWAKL 20的转录受到热胁迫的抑制，而阿坝和H2 O2处理诱导。CaWAKL 20基因的沉默增强辣椒的耐热性，而过表达降低拟南芥的耐热性。此外，过表达CaWAKL 20的拟南芥品系在种子萌发和根生长过程中对阿坝的敏感性较低。阿坝预处理提高了热胁迫下拟南芥幼苗的存活率，而CaWAKL 20的过表达降低了热胁迫下拟南芥幼苗的存活率。此外，在拟南芥CaWAKL 20过表达系中，一些ABA响应基因和一些耐热性关键调控基因的热诱导表达降低。这些结果表明CaWAKL 20通过降低ABA响应基因的表达负向调节植物的耐热性，为进一步研究WAKs/WAKL在环境胁迫下的作用机制奠定了基础。
Heat stress has become a major threat to crop production due to global warming; however, the mechanisms underlying plant high-temperature sensing are not well known. In plants, the membrane-anchored receptor-like kinases (RLKs) relay environmental signals into the cytoplasm. In a previous study, we isolated a wall-associated RLK-like (WAKL) gene CaWAKL20 from pepper (Capsicum annuum L.). Here, the amino acid sequence of CaWAKL20 was characterized and found to consist of conserved domains of WAK/WAKL family, including an extracellular region containing a GUB-WAK binding domain and a degenerated EGF2-like domain; a transmembrane region; and an intercellular region with an STKc catalytic domain. Moreover, CaWAKL20 transcription was inhibited by heat stress, whereas it was induced by both ABA and H2O2 treatments. Silencing of CaWAKL20 enhanced pepper thermotolerance, while overexpression decreased Arabidopsis thermotolerance. Additionally, Arabidopsis lines overexpressing CaWAKL20 showed less sensitivity to ABA during seed germination and root growth. Finally, the survival rate of Arabidopsis seedlings under heat stress treatment was enhanced by ABA pre-treatment, while it was compromised by the overexpression of CaWAKL20. Furthermore, the heat-induced expression of several ABA-responsive genes and some key regulator genes for thermotolerance was decreased in Arabidopsis CaWAKL20-overexpression lines. These results suggest that CaWAKL20 negatively modulates plant thermotolerance by reducing the expression of ABA-responsive genes, laying a foundation for further investigation into the functional mechanisms of WAKs/WAKLs in plants undergoing environmental stresses.