大白菜,科学上称为芸苔属油菜亚种。Pekinensis,在中国是一种非常受欢迎的蔬菜,其美味。然而,细菌性软腐病的发生对其生长和整体发育构成了重大威胁。因此,本研究旨在探讨大白菜对细菌性软腐病的防御机制。具体来说,调查的重点是了解大白菜根部周围土壤中存在的疾病与微生物群落之间的关系。与受巴西软杆菌引起的软腐病影响的微生物群落相比,健康大白菜植物根区土壤中存在的微生物群落组成存在显着差异。16SrRNA基因高通量测序分析结果显示变形杆菌丰度较低(8.39%),酸杆菌(0.85),鞘氨醇单胞菌(3.51%),和Vicinamibacteraceae(1.48%),而Firmicutes(113.76%),拟杆菌(8.71%),氯氟菌(4.89%),放线菌(1.71%),A4b(15.52%),Vicinamibacterales(1.62%),和Gemmaatimonadaceae(1.35%)在健康的植物土壤中更为普遍。同样,对ITS基因高通量测序结果的分析显示,衣原体的发生率降低(23.58%),担子菌(21.80%),斑纹菌(86.22%),健康土壤中的农产品(22.57%)。相比之下,被孢霉(50.72%),子囊(31.22%),Podospora(485.08%),和被孢霉(51.59%)在健康植物土壤中含量更高。此外,从大白菜病根区土壤中分离出15株细菌。这些分离的菌株证明了固氮的能力(ZT20,ZT26,ZT41,ZT45和ZT61除外),产生铁载体和吲哚乙酸(IAA),溶解磷酸盐。值得注意的是,ZT14(柠檬酸杆菌,freundii),ZT33(阴沟肠杆菌),ZT41(Myroidesodoratimimus),ZT52(芽孢杆菌),ZT58(巴氏克雷伯菌),ZT45(产气克雷伯菌),和ZT32(恶臭假单胞菌)表现出显着的生长促进作用,如植物生长促进(PGP)测试所确定的。因此,这项调查不仅证实了杭州大白菜中存在软腐病菌,中国,而且也加深了我们对大白菜抵抗软腐病引起的胁迫的防御机制的理解。此外,它确定了有希望的植物生长促进微生物(PGPM),可用于未来促进大白菜产业。
Chinese cabbage, scientifically known as Brassica rapa subsp. pekinensis, is a highly popular vegetable in
China for its delectable taste. However, the occurrence of bacterial soft rot disease poses a significant threat to its growth and overall development. Consequently, this study aimed to explore the defense mechanisms employed by Chinese cabbage against bacterial soft rot disease. Specifically, the investigation focused on understanding the relationship between the disease and the microbial communities present in the soil surrounding the roots of Chinese cabbage. Significant disparities were observed in the composition of microbial communities present in the root-zone soil of
healthy Chinese cabbage plants compared to those affected by Pectobacterium brasiliense-caused soft rot disease. The analysis of 16S rRNA gene high-throughput sequencing results revealed a lower abundance of Proteobacteria (8.39%), Acidobacteriot (0.85), Sphingomonas (3.51%), and Vicinamibacteraceae (1.48%), whereas Firmicutes (113.76%), Bacteroidota (8.71%), Chloroflexi (4.89%), Actinobacteriota (1.71%), A4b (15.52%), Vicinamibacterales (1.62%), and Gemmatimonadaceae (1.35%) were more prevalent in
healthy plant soils. Similarly, the analysis of ITS gene high-throughput sequencing results indicated a reduced occurrence of Chytridiomycota (23.58%), Basidiomycota (21.80%), Plectosphaerella (86.22%), and Agaricomycetes (22.57%) in healthy soils. In comparison, Mortierellomycota (50.72%), Ascomycota (31.22%), Podospora (485.08%), and Mortierella (51.59%) were more abundant in
healthy plant soils. In addition, a total of 15 bacterial strains were isolated from the root-zone soil of diseased Chinese cabbage plants. These isolated strains demonstrated the ability to fix nitrogen (with the exception of ZT20, ZT26, ZT41, ZT45, and ZT61), produce siderophores and indole acetic acid (IAA), and solubilize phosphate. Notably, ZT14 (Citrobacter freundii), ZT33 (Enterobacter cloacae), ZT41 (Myroides odoratimimus), ZT52 (Bacillus paramycoides), ZT58 (Klebsiella pasteurii), ZT45 (Klebsiella aerogenes), and ZT32 (Pseudomonas putida) exhibited significant growth-promoting effects as determined by the plant growth promotion (PGP) tests. Consequently, this investigation not only confirmed the presence of the soft rot pathogen in Chinese cabbage plants in Hangzhou,
China, but also advanced our understanding of the defense mechanisms employed by Chinese cabbage to combat soft rot-induced stress. Additionally, it identified promising plant-growth-promoting microbes (PGPMs) that could be utilized in the future to enhance the Chinese cabbage industry.