State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-product Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
College of Plant Protection, Hebei Agricultural University, Technological Innovation Center for Biological Control of Crop Diseases and Insect Pests of Hebei Province, Baoding 071000, China.
J Appl Microbiol. 2023 Sep 5;134(9). doi: 10.1093/jambio/lxad190.
Black scurf disease, caused by Rhizoctonia solani, is a severe soil-borne and tuber-borne disease, which occurs and spreads in potato growing areas worldwide and poses a serious threat to potato production. New biofungicide is highly desirable for addressing the issue, and natural products (NPs) from Xenorhabdus spp. provide prolific resources for biofungicide development. In this study, we aim to identify antifungal NPs from Xenorhabdus spp. for the management of this disease.
Out of the 22 Xenorhabdus strains investigated, Xenorhabdus budapestensis 8 (XBD8) was determined to be the most promising candidate with the measured IC50 value of its cell-free supernatant against R. solani as low as 0.19 ml l-1. The major antifungal compound in XBD8 started to be synthesized in the middle logarithmic phase and reached a stable level at stationary phase. Core gene deletion coupled with high-resolution mass spectrometry analysis determined the major antifungal NPs as fabclavine derivatives, Fcl-7 and 8, which showed broad-spectrum bioactivity against important pathogenic fungi. Impressively, the identified fabclavine derivatives effectively controlled black scurf disease in both greenhouse and field experiments, significantly improving tuber quality and increasing with marketable tuber yield from 29 300 to 35 494 kg ha-1, comparable with chemical fungicide fludioxonil.
The fabclavine derivatives Fcl-7 and 8 were determined as the major antifungal NPs in XBD8, which demonstrated a bright prospect for the management of black scurf disease.
由立枯丝核菌引起的黑疤病是一种严重的土传和块茎传病害，发生和传播于世界各地的马铃薯种植区，对马铃薯生产构成严重威胁。需要新型生物杀菌剂来解决这个问题，而从 Xenorhabdus 属获得的天然产物（NPs）为生物杀菌剂的开发提供了丰富的资源。在本研究中，我们旨在从 Xenorhabdus 属中鉴定出抗真菌 NPs，以防治该病害。
在所研究的 22 株 Xenorhabdus 菌株中，确定 Xenorhabdus budapestensis 8（XBD8）是最有前途的候选菌株，其无细胞上清液对 Rhizoctonia solani 的 IC50 值低至 0.19 ml l-1。XBD8 中主要的抗真菌化合物在对数中期开始合成，并在稳定期达到稳定水平。核心基因缺失结合高分辨率质谱分析确定主要的抗真菌 NPs 为 fabclavine 衍生物 Fcl-7 和 8，它们对重要的致病真菌表现出广谱的生物活性。令人印象深刻的是，鉴定出的 fabclavine 衍生物在温室和田间试验中有效控制了黑疤病，显著改善了块茎质量，并将商品薯产量从 29,300 增加到 35,494 公斤/公顷，与化学杀菌剂 fludioxonil 相当。
fabclavine 衍生物 Fcl-7 和 8 被确定为 XBD8 中的主要抗真菌 NPs，为黑疤病的防治提供了广阔的前景。
