Immune responses in plants can be triggered by damage/microbe-associated molecular patterns (DAMPs/MAMPs) upon recognition by plant pattern recognition receptors (PRRs). DAMPs are signaling molecules synthesized by plants or released from host cellular structures (e.g., plant cell walls) upon pathogen infection or wounding. Despite the hypothesized important role of plant cell wall-derived DAMPs in plant-pathogen interactions, a very limited number of these DAMPs are well characterized. Recent work demonstrated that pectin-enriched cell wall fractions extracted from the cell wall mutant impaired in Arabidopsis Response Regulator 6 (arr6), that showed altered disease resistance to several pathogens, triggered more intense immune responses than those activated by similar cell wall fractions from wild-type plants. It was hypothesized that arr6 cell wall fractions could be differentially enriched in DAMPs. In this work, we describe the characterization of the previous immune-active fractions of arr6 showing the highest triggering capacities upon further fractionation by chromatographic means. These analyses pointed to a role of pentose-based oligosaccharides triggering plant immune responses. The characterization of several pentose-based oligosaccharide structures revealed that β-1,4-xylooligosaccharides of specific degrees of polymerization and carrying arabinose decorations are sensed as DAMPs by plants. Moreover, the pentasaccharide 3³-α-L-arabinofuranosyl-xylotetraose (XA3XX) was found as a highly active DAMP structure triggering strong immune responses in Arabidopsis thaliana and enhancing crop disease resistance.

在植物模式识别受体（PRR）识别后，损伤/微生物相关分子模式（DAMP / MAMP）可以触发植物中的免疫反应。DAMP是由植物合成或在病原体感染或受伤时从宿主细胞结构（例如植物细胞壁）释放的信号传导分子。尽管推测植物细胞壁来源的DAMP在植物与病原体的相互作用中起着重要的作用，但这些DAMP的非常有限的特征已经得到很好的表征。最近的研究表明，从细胞壁突变体中提取的富含果胶的细胞壁部分会损害一种拟南芥 [R回应 [R调节器6 （6号），表现出对几种病原体的抗病性改变，引发了比由野生型植物的类似细胞壁部分所激活的免疫应答更强烈的免疫应答。据推测6号细胞壁部分可能在DAMPs中差异富集。在这项工作中，我们描述了以前的免疫活性部分的表征6号在通过色谱手段进一步分级分离时显示出最高的触发能力。这些分析指出了基于戊糖的寡糖触发植物免疫应答的作用。几种基于戊糖的寡糖结构的表征表明，特定的聚合度和带有阿拉伯糖修饰的β-1,4-木寡糖被植物感测为DAMP。此外，发现五糖3 ³ -α-L-阿拉伯呋喃糖基-木糖四糖（XA3XX）是高度活跃的DAMP结构，可触发强烈的免疫反应。拟南芥 增强作物的抗病能力。