多噬伯克霍尔德氏菌WS-FJ9对林木病原菌物的拮抗作用及代谢产物的稳定性

【背景】伯克霍尔德氏菌(Burkholderia)是一类重要的植物根际促生细菌,许多菌株具有抑制植物病原菌生长和促进植物生长等功能。【目的】探究高效解磷促生细菌多噬伯克霍尔德氏菌(B. multivorans) WS-FJ9对不同林木病原菌物的抑菌作用。【方法】采用平板对峙法检测菌株WS-FJ9对5株林木病原真菌和卵菌的抑制效果;基于比色法检测经菌株WS-FJ9处理后病原菌菌丝细胞内含物的变化;使用antiSMASH 5.0在线预测网站对其次生代谢物质进行预测;通过菌丝生长抑制速率法对其无菌发酵滤液的抑菌活性和稳定性进行研究。【结果】菌株WS-FJ9对5种林木病原菌均具有不同程度的抑制作用,其中菌悬液对樟疫霉(Phytophthora cinnamomi)的抑制作用最好,抑菌带宽度为14.82±0.20mm,无菌发酵滤液对真菌拟茎点霉(Phomopsismacrospore)和松杉球壳孢(Sphaeropsis sapinea)的抑制效果显著,抑菌率分别为62.22%和62.78%;经无菌发酵滤液处理后的病原菌菌丝内的丙二醛含量增高,还原糖和可溶性蛋白含量显著降低。WS-FJ9菌株的基因组中含27个不同的次级代谢产物编码基因簇,其中包含编码嗜铁素、细菌素和抗生素等抑菌基因簇;该菌株发酵液在高温、紫外照射和强酸强碱环境条件下及经蛋白酶处理后,其抑菌活性均未受到影响。【结论】多噬伯克霍尔德氏菌WS-FJ9对林木病原菌物具有很好的生防潜力。

Antagonism against forest pathogens and stability of fermentation broth of Burkholderia multivorans WS-FJ9

[Background] Some Burkholderia are important plant rhizosphere growth-promoting bacteria, which can inhibit plant pathogens and promote plant growth. [Objective] This study is to investigate the antagonistic ability of phosphate solubilizing and growth-promoting bacteria B. multivorans WS-FJ9 against different forest pathogens. [Methods] The antagonistic effect of WS-FJ9 strain against five forest pathogenics, the changes of mycelial contents of pathogenic fungi and oomycetes treated by strain WS-FJ9, the prediction of secondary metabolites and the antagonistic activity and stability of the fermentation broth were studied by using dual culture, colorimetric method, antiSMASH 5.0 online prediction site and mycelium growth inhibition rate method, respectively. [Results] The strain WS-FJ9 had different inhibitory effects against the five forest pathogens, in which the suspension had the best inhibitory effect against Phytophthora cinnamomi with the inhibitory zone width up to 14.82±0.20 mm. The fermentation broth of WS-FJ9 had significant inhibitory effect against Phomopsis macrospore and Sphaeropsis sapinea, and the inhibition rates were 62.22% and 62.78%, respectively. The contents of malondialdehyde (MDA), reducing sugar and soluble protein in the mycelia of pathogenic bacteria were increased after the treatment of sterile fermentation filtrate. The genome of the WS-FJ9 strain contained 27 different gene clusters encoding secondary metabolites, including genes encoding siderophores, bacteriocins and antibiotics. The antifungal activity of the fermentation broth of the strain was not affected under high temperature, ultraviolet irradiation, protease treatment, extreme acid and alkali treatment. [Conclusion] B. multivorans WS-FJ9 could be potentially used as biocontrol agent against forest pathogens.