Plants survey their environment for the presence of potentially harmful or beneficial microbes. During colonization, cell surface receptors perceive microbe‐derived or modified‐self ligands and initiate appropriate responses. The recognition of fungal chitin oligomers and the subsequent activation of plant immunity are well described. In contrast, the mechanisms underlying β‐glucan recognition and signaling activation remain largely unexplored. Here, we systematically tested immune responses towards different β‐glucan structures and show that responses vary between plant species. While leaves of the monocots Hordeum vulgare and Brachypodium distachyon can recognize longer (laminarin) and shorter (laminarihexaose) β‐1,3‐glucans with responses of varying intensity, duration and timing, leaves of the dicot Nicotiana benthamiana activate immunity in response to long β‐1,3‐glucans, whereas Arabidopsis thaliana and Capsella rubella perceive short β‐1,3‐glucans. Hydrolysis of the β‐1,6 side‐branches of laminarin demonstrated that not the glycosidic decoration but rather the degree of polymerization plays a pivotal role in the recognition of long‐chain β‐glucans. Moreover, in contrast to the recognition of short β‐1,3‐glucans in A. thaliana , perception of long β‐1,3‐glucans in N. benthamiana and rice is independent of CERK1, indicating that β‐glucan recognition may be mediated by multiple β‐glucan receptor systems.

中文翻译：

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植物物种对长和短 β-1,3 连接葡聚糖的特异性识别是由不同的受体系统介导的。


植物调查其环境中是否存在潜在有害或有益的微生物。在定殖过程中，细胞表面受体感知微生物衍生的或修饰的自身配体并启动适当的反应。真菌几丁质低聚物的识别和随后植物免疫的激活已有详细描述。相比之下，β-葡聚糖识别和信号激活的机制在很大程度上仍未被探索。在这里，我们系统地测试了针对不同 β-葡聚糖结构的免疫反应，并表明植物物种之间的反应有所不同。虽然单子叶植物大麦和二穗短柄草的叶子可以识别较长的（昆布多糖）和较短的（昆布六糖）β-1,3-葡聚糖，并具有不同强度、持续时间和时间的反应，但双子叶植物本塞姆氏烟草的叶子会激活免疫反应，以响应长的β-1,3-葡聚糖。 β-1,3-葡聚糖，而拟南芥和风荠菜感知短的 β-1,3-葡聚糖。昆布多糖 β-1,6 侧链的水解表明，在长链 β-葡聚糖的识别中起关键作用的不是糖苷装饰，而是聚合度。此外，与拟南芥中短β-1,3-葡聚糖的识别相反，本塞姆氏烟草和水稻中对长β-1,3-葡聚糖的感知不依赖于CERK1，这表明β-葡聚糖的识别可能与由多种β-葡聚糖受体系统介导。