Cyclic dipeptides (CDPs) are one of the simplest compounds produced by living organisms. Plant-growth promoting rhizobacteria (PGPRs) also produce CDPs that can induce disease resistance. Bacillus vallismortis strain BS07 producing various CDPs has been evaluated as a potential biocontrol agent against multiple plant pathogens in chili pepper. However, plant signal pathway triggered by CDPs has not been fully elucidated yet. Here we introduce four CDPs, cyclo(Gly-L-Pro) previously identified from Aspergillus sp., and cyclo(L-Ala-L-Ile), cyclo(L-Ala-L-Leu), and cyclo(LLeu-L-Pro) identified from B. vallismortis BS07, which induce disease resistance in Arabidopsis against Pseudomonas syringae infection. The CDPs do not directly inhibit fungal and oomycete growth in vitro. These CDPs require PHYTOALEXIN DEFICIENT4, SALICYLIC ACID INDUCTION DEFICIENT2, and NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 important for salicylic acid-dependent defense to induce resistance. On the other hand, regulators involved in jasmonate-dependent event, such as ETHYLENE RECEPTOR1, JASMONATE RESPONSE1, and JASMONATE INSENSITIVE1, are necessary to the CDP-induced resistance. Furthermore, treatment of these CDPs primes Arabidopsis plants to rapidly express PATHOGENESIS-RELATED PROTEIN4 at early infection phase. Taken together, we propose that these CDPs from PGPR strains accelerate activation of jasmonate-related signaling pathway during infection.

中文翻译：

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来自缬草芽孢杆菌BS07的环状二肽需要植物免疫的关键成分才能诱导拟南芥对假单胞菌感染的抗病性。

环二肽（CDP）是活生物体产生的最简单的化合物之一。促进植物生长的根际细菌（PGPR）也会产生CDP，从而诱导抗病性。已经评估了产生各种CDP的缬草芽孢杆菌菌株BS07作为针对辣椒中多种植物病原体的潜在生物防治剂。但是，尚未完全阐明CDP触发的植物信号途径。在这里，我们介绍了四个CDP，先前从曲霉属中鉴定出的环（Gly-L-Pro）和环（L-Ala-L-Ile），环（L-Ala-L-Leu）和环（LLeu-L） -Pro）从瓦氏芽孢杆菌BS07中鉴定，该菌株可诱导拟南芥对丁香假单胞菌的抗病性感染。CDP在体外不能直接抑制真菌和卵菌的生长。这些个CDP需要的植物抗毒素DEFICIENT4，水杨酸诱导DEFICIENT2，和发病机理相关的PROTEINS1 NONEXPRESSOR为水杨酸依赖的酸防御重要诱导阻力。另一方面，参与茉莉酸依赖性事件的调节剂，如乙烯受体1，茉莉响应和茉莉不敏感1，对于CDP诱导的抗性是必需的。此外，对这些CDP的处理可引发拟南芥植物快速表达与病原相关的蛋白4。在早期感染阶段。两者合计，我们建议这些PGPR菌株CDP加速感染过程中茉莉酸相关信号通路的激活。