College of Plant Protection, Hunan Agricultural University, Changsha 410128, China.
Hunan Plant Protection Institute, Hunan Academy of Agricultural Sciences, Changsha 410125, China.
Phytopathology. 2021 Mar;111(3):500-508. doi: 10.1094/PHYTO-05-20-0177-R. Epub 2021 Feb 9.
G-negative bacteria produce myriad -acyl-homoserine lactones (AHLs) that can function as quorum sensing (QS) signaling molecules. AHLs are also known to regulate various plant biological activities. -Coumaroyl-homoserine lactone (C-HSL) is the only QS molecule produced by a photosynthetic bacterium, . The role of C-HSL in the interaction between and plant has not been investigated. In this study, we investigated the effect of C-HSL on plant immunity and found that this QS molecule can induce a systemic resistance to (TMV) infection in . The results show that C-HSL treatment can prolong the activation of two mitogen-associated protein kinase genes (i.e., and ) and increase the expression of transcription factor as well as immune response marker genes and , leading to an increased accumulation of reactive oxygen species (ROS) in the TMV-infected plants. Our results also show that C-HSL treatment can increase activities of two ROS-scavenging enzymes, peroxidase and superoxide dismutase. Knockdown of or expression in plants through virus-induced gene silencing nullified or attenuated C-HSL-induced systemic resistance, indicating that the functioning of C-HSL relies on the activity of those two kinases. Meanwhile, C-HSL-pretreated plants also showed a strong induction of kinase activities of NbSIPK and NbWIPK after TMV inoculation. Taken together, our results demonstrate that C-HSL treatment increases plant resistance to TMV infection, which is helpful to uncover the outcome of interaction between and its host plants.
革兰氏阴性菌产生多种酰基高丝氨酸内酯（AHLs），可作为群体感应（QS）信号分子。AHLs 还被认为可以调节各种植物的生物活性。-香豆酰高丝氨酸内酯（C-HSL）是唯一由光合细菌产生的 QS 分子，。C-HSL 在与植物相互作用中的作用尚未被研究过。在这项研究中，我们研究了 C-HSL 对植物免疫的影响，发现这种 QS 分子可以诱导 对 （TMV）感染的全身性抗性。结果表明，C-HSL 处理可以延长两种丝裂原激活蛋白激酶基因（即 和 ）的激活，并增加转录因子 以及免疫反应标记基因 和 的表达，导致 TMV 感染植物中活性氧（ROS）的积累增加。我们的结果还表明，C-HSL 处理可以增加两种 ROS 清除酶，过氧化物酶和超氧化物歧化酶的活性。通过病毒诱导的基因沉默敲低 或 在 植物中的表达，消除或减弱了 C-HSL 诱导的全身性抗性，表明 C-HSL 的功能依赖于这两种激酶的活性。同时，用 C-HSL 预处理的植物在接种 TMV 后也表现出 NbSIPK 和 NbWIPK 激酶活性的强烈诱导。总之，我们的研究结果表明，C-HSL 处理可提高植物对 TMV 感染的抗性，这有助于揭示 与宿主植物相互作用的结果。
