Institute of Biology Co., Ltd., Henan Academy of Sciences, Key Laboratory of Microbial Engineering of Henan, Zhengzhou, 450008, China.
Braz J Microbiol. 2023 Mar;54(1):361-370. doi: 10.1007/s42770-022-00896-x. Epub 2022 Dec 27.
Peanut stem rot caused by Sclerotium rolfsii Sacc. is the most common disease of peanut worldwide and has become increasingly serious in recent years. This study is aimed at obtaining peanut endophytic bacteria with high antagonistic/protective effects against peanut stem rot. In total, 45 bacterial strains were isolated from healthy peanut plants from a severely impacted area. Of these, 6 exhibited antagonistic activity against S. rolfsii, including F-1 and R-11 with the most robust activity with an inhibition zone width of 20.25 and 15.49 mm, respectively. These two were identified as Bacillus sp. and Burkholderia sp., respectively, based on morphological, physiological, and biochemical characteristics and 16S rDNA sequencing. To the best of our knowledge, this is the first study to report the Burkholderia sp. antagonistic effect on S. rolfsii as a biological control agent for peanut stem rot. Their culture filtrates potently inhibited the hyphal growth, sclerotial formation, and germination of S. rolfsii. Also, the strain-produced volatile compounds inhibited the fungal growth. Pot experiments showed that F-1 and R-11 significantly reduced the peanut stem rot disease with the efficacy of 77.13 and 64.78%, respectively, which was significantly higher compared with carbendazim medicament (35.22%; P < 0.05). Meanwhile, F-1 and R-11 improved the activity of plant defense enzymes such as phenylalaninase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) enhancing the systemic resistance of the peanut plants. This study demonstrated that Bacillus sp. F-1 and Burkholderia sp. R-11, with a strong antagonistic effect on S. rolfsii, can be potential biocontrol agents for peanut stem rot.
由齐整小核菌（Sclerotium rolfsii Sacc.）引起的花生茎腐病是全球范围内最常见的花生病害，近年来变得越来越严重。本研究旨在获得对花生茎腐病具有高拮抗/保护作用的花生内生细菌。从受严重影响地区的健康花生植株中总共分离出 45 株细菌。其中，有 6 株对 S. rolfsii 表现出拮抗活性，其中 F-1 和 R-11 的活性最强，抑菌圈宽度分别为 20.25 和 15.49mm。根据形态学、生理学、生物化学特征和 16S rDNA 测序，这两种细菌分别鉴定为芽孢杆菌和伯克霍尔德氏菌。据我们所知，这是首次报道伯克霍尔德氏菌作为花生茎腐病生物防治剂对 S. rolfsii 的拮抗作用。它们的培养液能强烈抑制齐整小核菌的菌丝生长、菌核形成和萌发。此外，该菌株产生的挥发性化合物也抑制了真菌的生长。盆栽试验表明，F-1 和 R-11 可显著降低花生茎腐病的发病率，防治效果分别为 77.13%和 64.78%，显著高于多菌灵药剂（35.22%）（P<0.05）。同时，F-1 和 R-11 提高了苯丙氨酸解氨酶（PAL）、多酚氧化酶（PPO）和过氧化物酶（POD）等植物防御酶的活性，增强了花生植株的系统抗性。本研究表明，对 S. rolfsii 具有强烈拮抗作用的芽孢杆菌 F-1 和伯克霍尔德氏菌 R-11 可能是花生茎腐病的潜在生物防治剂。
