Department of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy.
Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125, Naples, Italy.
Carbohydr Polym. 2022 Feb 1;277:118839. doi: 10.1016/j.carbpol.2021.118839. Epub 2021 Nov 8.
Lipopolysaccharides, the major outer membrane components of Gram-negative bacteria, are crucial actors of the host-microbial dialogue. They can contribute to the establishment of either symbiosis or bacterial virulence, depending on the bacterial lifestyle. Plant microbiota shows great complexity, promotes plant health and growth and assures protection from pathogens. How plants perceive LPS from plant-associated bacteria and discriminate between beneficial and pathogenic microbes is an open and urgent question. Here, we report on the structure, conformation, membrane properties and immune recognition of LPS isolated from the Arabidopsis thaliana root microbiota member Herbaspirillum sp. Root189. The LPS consists of an O-methylated and variously acetylated D-rhamnose containing polysaccharide with a rather hydrophobic surface. Plant immunology studies in A. thaliana demonstrate that the native acetylated O-antigen shields the LPS from immune recognition whereas the O-deacylated one does not. These findings highlight the role of Herbaspirillum LPS within plant-microbial crosstalk, and how O-antigen modifications influence membrane properties and modulate LPS host recognition.
脂多糖是革兰氏阴性细菌外膜的主要成分，是宿主-微生物对话的关键因素。它们可以促进共生或细菌毒力的建立，具体取决于细菌的生活方式。植物微生物组具有高度复杂性，能促进植物健康和生长，并确保免受病原体的侵害。植物如何感知植物相关细菌中的 LPS，并区分有益和致病微生物，是一个悬而未决的问题。在这里，我们报告了从拟南芥根微生物群成员 Herbaspirillum sp. Root189 中分离出的 LPS 的结构、构象、膜特性和免疫识别。该 LPS 由含有 O-甲基化和各种乙酰化 D-鼠李糖的多糖组成，具有相当疏水的表面。在拟南芥中的植物免疫学研究表明，天然乙酰化的 O-抗原使 LPS 免受免疫识别，而 O-去乙酰化的则不受影响。这些发现强调了 Herbaspirillum LPS 在植物-微生物串扰中的作用，以及 O-抗原修饰如何影响膜特性并调节 LPS 宿主识别。
