Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
Department of Horticulture, Ghazi University, Dera Ghazi Khan, Pakistan.
Appl Environ Microbiol. 2023 Feb 28;89(2):e0203622. doi: 10.1128/aem.02036-22. Epub 2023 Feb 6.
The oomycete Pythium oligandrum is a soil-inhabiting parasite and predator of both fungi and oomycetes, and uses hydrolytic enzymes extensively to penetrate and hydrolyze its host or prey. Other mechanisms have been studied less, and we investigated the contribution of -produced volatile organic compounds (VOCs) to parasitism. The growth-inhibiting activity of VOCs was tested on -a host or prey of -coupled with electron microscopy, and biochemical and transcriptomic analyses. The -produced VOCs reduced growth by 80% and zoospore levels by 60%. Gas chromatography-mass spectrometry (GC-MS) identified 23 VOCs, and methyl heptenone, d-limonene, 2-undecanone, and 1-octanal were potent inhibitors of growth and led to increased production of reactive oxygen species at a concentration that did not inhibit growth. Exposure to the VOCs led to shrinkage of hyphae and lysis of the cellular membranes and organelles. Transcriptomics of exposed to the VOCs at increasing levels of growth inhibition initially showed a strong upregulation of putative detoxification-related genes that was not maintained later. The inhibition of growth continued immediately after the exposure to the VOCs was discontinued and led to the reduced infection of its plant hosts. The VOCs produced by could be another factor alongside hydrolytic enzymes contributing to its ecological role as a microbial parasite in particular ecological niches such as in soil, and may also contribute to the biocontrol of diseases using commercial preparations. Microbe-microbe interactions in nature are multifaceted, with multiple mechanisms of action, and are crucial to how plants interact with microbes. Volatile organic compounds (VOCs) have diverse functions, including contributing to parasitism in ecological interactions and potential applications in biocontrol. The microbial parasite is well known for using hydrolytic enzymes as part of its parasitism. We found that VOCs reduced the growth of, and caused major damage to, the hyphae of (a host or prey of ). Transcriptomic analyses of exposed to the VOCs revealed the upregulation of genes potentially involved in an attempt to detoxify the VOCs. The inhibitory effects of the VOCs had a knock-on effect by reducing the virulence of toward its plant hosts. The VOCs could contribute to its ecological role as a microbial parasite. The VOCs analyzed here may also contribute to the biocontrol of diseases using commercial preparations.
卵菌纲寡养单胞菌是一种土壤寄生性寄生虫和真菌及卵菌纲的捕食者，广泛利用水解酶穿透和水解其宿主或猎物。其他机制的研究较少，我们研究了 -产生的挥发性有机化合物（VOCs）对寄生的贡献。通过电子显微镜、生物化学和转录组学分析，测试了 VOCs 对 -宿主或猎物的生长抑制活性。-产生的 VOCs 使 -生长抑制 80%，游动孢子水平抑制 60%。气相色谱-质谱联用（GC-MS）鉴定出 23 种 VOCs，甲基庚烯酮、柠檬烯、2-十一酮和 1-辛醛是生长的有效抑制剂，并在不抑制生长的浓度下导致活性氧的产生增加。暴露于 VOCs 导致菌丝收缩和细胞膜和细胞器溶解。随着生长抑制程度的增加，暴露于 VOCs 的 -转录组最初显示出强烈的解毒相关基因上调，但后来并未维持。暴露于 VOCs 后，生长立即受到抑制，导致其植物宿主的感染减少。-产生的 VOCs 可能是水解酶之外的另一个因素，有助于其在特定生态位（如土壤）中作为微生物寄生虫的生态作用，并可能有助于使用 -商业制剂进行疾病的生物防治。自然界中的微生物-微生物相互作用是多方面的，具有多种作用机制，对植物与微生物的相互作用至关重要。挥发性有机化合物（VOCs）具有多种功能，包括在生态相互作用中促进寄生作用和在生物防治中的潜在应用。微生物寄生虫寡养单胞菌以使用水解酶作为其寄生作用的一部分而闻名。我们发现，-VOCs 降低了宿主或猎物 -的生长，并对其菌丝造成严重损害。暴露于 VOCs 的 -转录组分析显示，潜在参与解毒 VOCs 的基因上调。VOCs 的抑制作用通过降低 -对其植物宿主的毒力产生连锁反应。-VOCs 可能有助于其作为微生物寄生虫的生态作用。本文分析的 VOCs 也可能有助于使用 -商业制剂进行疾病的生物防治。
