Liu Jianfeng, Feng Runxia, Fu Xiaohong, Zhao Jie, Zhang Sufang, Wang Jianjun, Wang Xiaoyi, Wei Jianrong
School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, China.
Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China.
Pest Manag Sci. 2022 Apr;78(4):1386-1397. doi: 10.1002/ps.6755. Epub 2021 Dec 31.
Velvet ash (Fraxinus velutina Torr.) is an important wood and ornamental tree species. Emerald ash borer (EAB), Agrilus planipennis Fairmaire, is a major wood borer of velvet ash. The aim of this study was to identify the secondary metabolites of velvet ash involved in regulating the dominant bacterium group of EAB.
The amount of lignans in the phloem of infested trees had increased by 290.96% because of A. planipennis infection. The addition of lignans to the artificial diet significantly reduced the weight of the larvae and decreased the dominant bacterial group in the larval midgut, such as Pseudomonadaceae, Xanthomonadaceae, and Enterobacteriaceae. The FvPLR1, a key gene for lignan synthesis, was obtained based on the phloem transcriptome of velvet ash. The expression of FvPLR1 in the phloem of the infested tree was significantly higher than that in the noninfested tree. Meanwhile, FvPLR1 silenced by virus-induced gene silencing showed that its expression level and the lignan content were decreased by 69.91% and 31.65%, respectively. Interestingly, silencing FvPLR1 induced alterations in the dominant bacteria group in the larvae, with the reverse trend in the lignan-fed treatment.
The evidence showed that FvPLR1 was a positive regulator. The increasing synthesis of lignans leads to resistance improvement in velvet ash, which will provide comprehensive insights into the tree defense system to wood borer infestation. © 2021 Society of Chemical Industry.
绒毛白蜡（Fraxinus velutina Torr.）是一种重要的用材和观赏树种。光肩星天牛（Agrilus planipennis Fairmaire）是绒毛白蜡的主要蛀干害虫。本研究旨在鉴定绒毛白蜡中参与调节光肩星天牛优势菌群的次生代谢产物。
由于光肩星天牛的侵染，受侵染树木韧皮部中木脂素的含量增加了290.96%。在人工饲料中添加木脂素显著降低了幼虫的体重，并减少了幼虫中肠中的优势菌群，如假单胞菌科、黄单胞菌科和肠杆菌科。基于绒毛白蜡韧皮部转录组获得了木脂素合成的关键基因FvPLR1。FvPLR1在受侵染树木韧皮部中的表达显著高于未受侵染树木。同时，通过病毒诱导基因沉默使FvPLR1沉默，结果显示其表达水平和木脂素含量分别下降了69.91%和31.65%。有趣的是，沉默FvPLR1会导致幼虫优势菌群发生变化，与木脂素喂养处理的趋势相反。
证据表明FvPLR1是一个正向调节因子。木脂素合成的增加导致绒毛白蜡抗性提高，这将为树木对蛀干害虫侵染的防御系统提供全面的见解。© 2021化学工业协会。
