Beyond their function as structural barriers, plant cell walls are essential elements for the adaptation of plants to environmental conditions. Cell walls are dynamic structures whose composition and integrity can be altered in response to environmental challenges and developmental cues. These wall changes are perceived by plant sensors/receptors to trigger adaptative responses during development and upon stress perception. Plant cell wall damage caused by pathogen infection, wounding, or other stresses leads to the release of wall molecules, such as carbohydrates (glycans), that function as damage-associated molecular patterns (DAMPs). DAMPs are perceived by the extracellular ectodomains (ECDs) of pattern recognition receptors (PRRs) to activate pattern-triggered immunity (PTI) and disease resistance. Similarly, glycans released from the walls and extracellular layers of microorganisms interacting with plants are recognized as microbe-associated molecular patterns (MAMPs) by specific ECD-PRRs triggering PTI responses. The number of oligosaccharides DAMPs/MAMPs identified that are perceived by plants has increased in recent years. However, the structural mechanisms underlying glycan recognition by plant PRRs remain limited. Currently, this knowledge is mainly focused on receptors of the LysM-PRR family, which are involved in the perception of various molecules, such as chitooligosaccharides from fungi and lipo-chitooligosaccharides (i.e., Nod/MYC factors from bacteria and mycorrhiza, respectively) that trigger differential physiological responses. Nevertheless, additional families of plant PRRs have recently been implicated in oligosaccharide/polysaccharide recognition. These include receptor kinases (RKs) with leucine-rich repeat and Malectin domains in their ECDs (LRR-MAL RKs), RECEPTOR-LIKE KINASE 1-LIKE group (CrRLK1L) with Malectin-like domains in their ECDs, as well as wall-associated kinases, lectin-RKs, and LRR-extensins. The characterization of structural basis of glycans recognition by these new plant receptors will shed light on their similarities with those of mammalians involved in glycan perception. The gained knowledge holds the potential to facilitate the development of sustainable, glycan-based crop protection solutions.

中文翻译：

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植物细胞壁介导的抗病性：当前的理解和未来的前景


除了作为结构屏障的功能外，植物细胞壁还是植物适应环境条件的重要元素。细胞壁是动态结构，其组成和完整性可以根据环境挑战和发育线索而改变。这些壁的变化被植物传感器/受体感知，以在发育过程中和应激感知时触发适应性反应。由病原体感染、受伤或其他应激引起的植物细胞壁损伤会导致细胞壁分子的释放，例如碳水化合物（聚糖），这些分子作为损伤相关分子模式（DAMP）发挥作用。 DAMP 被模式识别受体 (PRR) 的胞外域 (ECD) 感知，以激活模式触发免疫 (PTI) 和抗病能力。同样，从与植物相互作用的微生物壁和细胞外层释放的聚糖被触发 PTI 反应的特定 ECD-PRR 识别为微生物相关分子模式 (MAMP)。近年来，植物感知的寡糖 DAMP/MAMP 数量有所增加。然而，植物 PRR 识别聚糖的结构机制仍然有限。目前，这些知识主要集中在 LysM-PRR 家族的受体上，这些受体参与各种分子的感知，例如来自真菌的壳寡糖和脂壳寡糖（即分别来自细菌和菌根的 Nod/MYC 因子）。引发不同的生理反应。然而，最近有其他植物 PRR 家族与寡糖/多糖识别有关。 这些包括在其 ECD 中具有富含亮氨酸重复序列和 Mallectin 结构域的受体激酶 (RK) (LRR-MAL RK)、在其 ECD 中具有 Mallectin 样结构域的受体样激酶 1-LIKE 基团 (CrRLK1L)，以及壁-相关激酶、凝集素-RK 和 LRR-延伸蛋白。这些新植物受体识别聚糖的结构基础的表征将揭示它们与涉及聚糖感知的哺乳动物的相似性。所获得的知识有可能促进可持续的、基于聚糖的作物保护解决方案的开发。