Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0304, United States.
ACS Chem Biol. 2021 Jun 18;16(6):1079-1089. doi: 10.1021/acschembio.1c00260. Epub 2021 May 25.
are new biocontrol agents known for their prolific production of lytic enzymes and bioactive metabolites. is a predator of fungi and produces several structurally distinct antimicrobial compounds, such as the antifungal HSAF (heat stable antifungal factor) and analogs. The mechanism by which interacts with fungal prey is not well understood. Here, we found that the production of HSAF and analogs in OH11 was significantly induced in media supplemented with ground fungal mycelia or chitin. In the OH11 genome, we identified a gene () that was annotated to encode a chitin-binding protein. The stimulation of HSAF and analogs by chitin was diminished when was deleted. We expressed the gene in and demonstrated that purified LeLPMO10A oxidatively cleaved chitin into oligomeric products, including 1,5 δ-lactones and aldonic acids. The results revealed that encodes a lytic polysaccharide monooxygenase, which has not been reported in . The metabolite analysis, antifungal assay, and proteomic analysis showed that the antifungal compounds and the chitin-cleaving LeLPMO10A are colocalized in outer membrane vesicles. The enzymatic products that resulted from LeLPMO10A-cleaved chitin also significantly induced HSAF and analogs in OH11. Scanning electron microscopic analysis indicated that spherical vesicles were formed outside of OH11 cells, and fewer OH11 cells were observed to attach to fungal hyphae when was deleted. Together, the study revealed a previously uncharacterized synergistic strategy utilized by the predatory during interaction with fungal prey.
是一种真菌捕食者，能够产生多种结构独特的抗菌代谢物和裂解酶。它与真菌猎物相互作用的机制尚不清楚。在这里，我们发现，在补充了真菌菌丝或几丁质的培养基中，OH11 中 HSAF（热稳定抗真菌因子）和类似物的产量显著增加。在 OH11 的基因组中，我们鉴定出一个基因 ()，该基因被注释为编码一种几丁质结合蛋白。当缺失时，几丁质对 HSAF 和类似物的刺激作用减弱。我们在 中表达了该基因，并证明纯化的 LeLPMO10A 将几丁质氧化裂解成寡聚产物，包括 1,5 δ-内酰胺和醛酸。结果表明 编码一种溶细胞多糖单加氧酶，这在 中尚未报道过。代谢物分析、抗真菌测定和蛋白质组学分析表明，抗真菌化合物和裂解几丁质的 LeLPMO10A 都定位于外膜囊泡中。由 LeLPMO10A 裂解几丁质产生的酶产物也显著诱导了 OH11 中 HSAF 和类似物的产生。扫描电子显微镜分析表明，在 OH11 细胞外形成了球形囊泡，并且当缺失时，观察到更少的 OH11 细胞附着在真菌菌丝上。总之，该研究揭示了捕食性 在与真菌猎物相互作用过程中使用的一种以前未被描述的协同策略。
