Department of Plant Science, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China.
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
Planta. 2021 Jan 6;253(2):25. doi: 10.1007/s00425-020-03546-4.
The presence of Bacillus cereus plays a key role in clubroot suppression and improves plant biomass in pak choi. B. cereus is reported for the first time as a novel biocontrol agent against clubroot. Plasmodiophora brassicae Woronin causes a devastating infectious disease known as clubroot that is damaging to cruciferous vegetables. This study aimed to isolate beneficial bacteria from the rhizosphere soil of pak choi (Brassica campestris sp. chinensis) and to evaluate the ability of the isolate to reduce the severity of clubroot. Strains obtained from the rhizosphere of symptomless pak choi were first selected on the basis of their germination inhibition rate and effects on the viability of P. brassicae resting spores. Eight bacterial isolates had inhibitory effects against the resting spores of clubroot causing pathogen. However, MZ-12 showed the highest inhibitory effect at 73.4%. Inoculation with MZ-12 enhanced the plant biomass relative to plants grown without MZ-12 as well as P. brassicae infected plants. Furthermore, enhanced antioxidant enzymatic activities were observed in clubroot-infected plants during bacterial association. Co-inoculation of the plant with both P. brassicae and MZ-12 resulted in a 64% reduction of gall formation in comparison to plants inoculated with P. brassicae only. Three applications of MZ-12 to plants infected with P. brassicae at 7, 14 and 21 days after seeding (DAS) were more effective than one application and repressed root hair infection. According to 16S rDNA sequence analysis, strain MZ-12 was identified as had a 100% sequence similarity with type strain Bacillus cereus. The findings of the present study will facilitate further investigation into biological mechanisms of cruciferous clubroot control.
蜡状芽孢杆菌的存在对根肿病的抑制起着关键作用,并提高了小白菜的植物生物量。蜡状芽孢杆菌首次被报道为一种防治根肿病的新型生物防治剂。菜豆黄花叶病毒(Plasmodiophora brassicae Woronin)引起一种破坏性的传染病,称为根肿病,对十字花科蔬菜造成损害。本研究旨在从小白菜( Brassica campestris sp. chinensis )根际土壤中分离有益细菌,并评估该分离物减轻根肿病严重程度的能力。首先根据对小白菜无症状根际土壤中分离株的发芽抑制率和对菜豆黄花叶病毒休止孢子活力的影响,选择了根际土壤分离株。有 8 株细菌分离株对引起根肿病的病原休止孢子有抑制作用。然而,MZ-12 的抑制效果最高,达到 73.4%。与未接种 MZ-12 的植物以及感染菜豆黄花叶病毒的植物相比,接种 MZ-12 提高了植物生物量。此外,在细菌共生期间观察到感染根肿病的植物中抗氧化酶活性增强。与仅接种菜豆黄花叶病毒的植物相比,将植物与菜豆黄花叶病毒和 MZ-12 共同接种可使根瘤形成减少 64%。在接种菜豆黄花叶病毒后 7、14 和 21 天(DAS)对感染植物进行三次 MZ-12 处理比一次处理更有效,并抑制根毛感染。根据 16S rDNA 序列分析,MZ-12 菌株与模式菌株蜡状芽孢杆菌的序列相似度为 100%。本研究的结果将有助于进一步研究十字花科根肿病防治的生物学机制。