CRISPR/Cas9 Disruption of UGT71L1 in Poplar Connects Salicinoid and Salicylic Acid Metabolism and Alters Growth and Morphology

第一作者：Harley Gordon

第一单位：维多利亚大学

通讯作者：C Peter Constabel

 Abstarct 

背景回顾：Salicinoids are salicyl alcohol-containing phenolic glycosides with strong anti-herbivore effects found only in poplars and willows. Their biosynthesis is poorly understood but recently a UDP-dependent glycosyltransferase, UGT71L1, was shown to be required for salicinoid biosynthesis in poplar tissue cultures. UGT71L1 specifically glycosylates salicyl benzoate, a proposed salicinoid intermediate. 

Salicinoids是一类含有酚苷的水杨醇，具有非常强的抗草食作用，仅在杨树和柳树中被发现。目前，我们对于这类化合物的生物合成所知甚少，但最近在杨树组织培养的研究中，发现salicinoid的生物合成需要UDP依赖的糖基转移酶UGT71L1。UGT71L1能够特异性糖基化水杨酸苯甲酸酯，而后者被认为是salicinoid的中间体。

主要发现：Here we analyzed transgenic CRISPR/Cas9-generated UGT71L1 knock-out plants. 

本文中，作者分析了CRISPR/Cas9介导的UGT71L1基因敲除植株。

结果1-UGT71L1敲除表型：Metabolomic analyses revealed substantial reductions in the major salicinoids, confirming the central role of the enzyme in salicinoid biosynthesis. Correspondingly, UGT71L1 knock-outs were preferred to wild-type by white tussock moth (Orgyia leucostigma) larvae in bioassays. Greenhouse-grown knock-out plants showed substantial growth alterations, with decreased internode length and smaller serrated leaves. Reinserting a functional UGT71L1 gene in a transgenic rescue experiment demonstrated that these effects were due only to the loss of UGT71L1.

代谢组学分析显示，主要的salicinoids显著减少，证实了该酶在salicinoid生物合成中的核心作用。另外，相比于野生型，白斑毒蛾（Orgyia leucostigma）幼虫更偏爱UGT71L1敲除植株。温室栽培的敲除植株表现出显著的生长变化，包括缩短的节间长度和更小的锯齿叶片。在敲除植株植株中重新转进一个功能性的UGT71L1基因能够拯救敲除植株的表型，这说明敲除植株的表型都是由UGT71L1基因的功能缺失所导致的。

结果2-UGT71L1与SA、生长：The knock-outs contained elevated salicylate (SA) and jasmonate (JA) concentrations, and also had enhanced expression of SA- and JA-related genes. SA is predicted to be released by UGT71L1 disruption, if salicyl salicylate is a pathway intermediate and UGT71L1 substrate. This idea was supported by showing that salicyl salicylate can be glucosylated by recombinant UGT71L1, providing a potential link of salicinoid metabolism to SA and growth impacts. 

UGT71L1基因被敲除后，敲除植株的水杨酸（SA）和茉莉酸（JA）浓度升高，并且与SA和JA相关的基因表达量也有所提升。如果水杨酸水杨酸醋同时水杨酸合成途径中的一个中间物和UGT71L1蛋白的底物，那么UGT71L1基因的敲除预计会合成更多的SA。进一步的实验表明UGT71L1重组蛋白能够糖基化水杨酸水杨酸醋，从而验证了之前的假设，同时也为salicinoid代谢与和SA以及生长影响提供了潜在的联系。

结论：Connecting this pathway with growth could imply that salicinoids are under additional evolutionary constraints beyond selective pressure by herbivores.

该途径与生长之间的关联暗示，除了草食动物的选择压力之外，salicinoids可能还受到其他演化压力的限制。

** C Peter Constabel **

doi: https://doi.org/10.1093/plcell/koac135​

Journal: The Plant Cell

 Published date: May 09, 2022

CITE

Harley Gordon, Christin Fellenberg, Nathalie D Lackus, Finn Archinuk, Amanda Sproule, Yoko Nakamura, Tobias G Köllner, Jonathan Gershenzon, David P Overy, C Peter Constabel, CRISPR/Cas9 Disruption of UGT71L1 in Poplar Connects Salicinoid and Salicylic Acid Metabolism and Alters Growth and Morphology. The Plant Cell, 2022. DOI: https://doi.org/10.1093/plcell/koac135.