Department of Agricultural Chemistry, Environmentally-Friendly Agricultural Research Center, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea.
Department of Agricultural and Biological Chemistry, Environmentally-Friendly Agricultural Research Center, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea.
Microb Pathog. 2024 May;190:106604. doi: 10.1016/j.micpath.2024.106604. Epub 2024 Mar 14.
Early blight caused by Alternaria solani is a common foliar disease of potato around the world, and serious infections result in reduced yields and marketability due to infected tubers. The major aim of this study is to figure out the synergistic effect between microorganism and fungicides and to evaluate the effectiveness of Bacillus subtilis NM4 in the control of early blight in potato. Based on its colonial morphology and a 16S rRNA analysis, a bacterial antagonist isolated from kimchi was identified as B. subtilis NM4 and it has strong antifungal and anti-oomycete activity against several phytopathogenic fungi and oomycetes. The culture filtrate of strain NM4 with the fungicide effectively suppressed the mycelial growth of A. solani, with the highest growth inhibition rate of 83.48%. Although exposure to culture filtrate prompted hyphal alterations in A. solani, including bulging, combining it with the fungicide caused more severe hyphal damage with continuous bulging. Surfactins and fengycins, two lipopeptide groups, were isolated and identified as the main compounds in two fractions using LC-ESI-MS. Although the surfactin-containing fraction failed to inhibit growth, the fengycin-containing fraction, alone and in combination with chlorothalonil, restricted mycelial development, producing severe hyphal deformations with formation of chlamydospores. A pot experiment combining strain NM4, applied as a broth culture, with fungicide, at half the recommended concentration, resulted in a significant reduction in potato early blight severity. Our results indicate the feasibility of an integrated approach for the management of early blight in potato that can reduce fungicide application rates, promoting a healthy ecosystem in agriculture.
早疫病由交链孢菌引起，是世界各地马铃薯叶片的常见病害，严重感染会导致产量和商品性下降，因为感染的块茎。本研究的主要目的是研究微生物与杀菌剂之间的协同作用，并评估枯草芽孢杆菌 NM4 在控制马铃薯早疫病中的效果。从泡菜中分离出的一种细菌拮抗物根据其菌落形态和 16S rRNA 分析，被鉴定为枯草芽孢杆菌 NM4，它对几种植物病原菌真菌和卵菌具有很强的抗真菌和抗卵菌活性。该菌株 NM4 的培养液与杀菌剂有效抑制了交链孢菌的菌丝生长，最高抑制率为 83.48%。虽然暴露于培养液会促使交链孢菌的菌丝发生变化，包括肿胀，但与杀菌剂结合会导致更严重的菌丝损伤，持续肿胀。使用 LC-ESI-MS 从两个馏分中分离并鉴定出两种脂肽群，即表面活性剂和丰霉素，作为主要化合物。虽然含表面活性剂的馏分不能抑制生长，但含丰霉素的馏分，单独使用和与代森锰锌联合使用，都能限制菌丝的发育，产生严重的菌丝变形，并形成厚垣孢子。将 NM4 菌株与杀菌剂结合，以半推荐浓度作为菌液培养物进行盆载试验，可显著降低马铃薯早疫病的严重程度。我们的结果表明，采用枯草芽孢杆菌 NM4 结合杀菌剂的综合防治方法来防治马铃薯早疫病是可行的，这种方法可以降低杀菌剂的使用量，促进农业生态系统的健康。
