基于嗜铁素介导的吡咯伯克霍尔德氏菌JK-SH007促生作用机制研究

【目的】分析吡咯伯克霍尔德菌 JK-SH007基于产嗜铁素的促生作用机制。【方法】通过萃取、过柱等操作,分离纯化,获得吡咯伯克霍尔德菌 JK-SH007所产嗜铁素(简称JK-SH007-嗜铁素)的纯品,通过HPLC和LC-MS对其结构进行鉴定,通过与病原菌共培养,测菌丝干质量的方法,分析其对3种杨树溃疡病病原真菌(金黄壳囊孢、拟茎点霉和七叶树壳梭孢)的抑制作用,以商品嗜铁素磺酸去铁胺(DFOB)作为对照,比较JK-SH007-细菌重悬液、1.4 mg/mL JK-SH007-嗜铁素溶液对番茄、黄瓜种子的萌发作用,并继续观察对黄瓜幼苗的促生作用和番茄挂果果品改善效果,评估JK-SH007-嗜铁素的直接与间接的促生作用。【结果】与对照相比,JK-SH007-嗜铁素显示出比DFOB更有效的抑制真菌生长的活性,3种病原真菌抑菌率分别为(89±0.9)%,(76±0.6)%和(90±0.7)%。同时,与JK-SH007-菌悬液相比,JK-SH007-嗜铁素溶液对番茄、黄瓜种子和幼苗活力的提高表现更好,而对于黄瓜幼苗的生长促进作用和番茄挂果的改善作用,其效果与菌悬液相近。【结论】嗜铁素为促生菌吡咯伯克霍尔德氏菌 JK-SH007的主要促生生防因子之一。

Mechanism of Burkholderia pyrrocinia JK-SH007 growth-promoting to plant via siderophore-mediation

【Objective】We aimed to explore the mechanism by which Burkholderia pyrrocinia JK-SH007, a gram-negative bacterium, promotes plant growth; we explored the effects of siderophores on pathogenic fungal activity and plant growth. 【Method】 A sample of JK-SH007-siderophores was isolated and purified using column chromatography, and the siderophore structure was identified using high-performance liquid chromatography and liquid chromatography-mass spectrometry. We cultivated three pathogens that cause poplar canker (Cytospora chrysosperma, Phomopsis macrospora and Fusicoccum aesculi) with siderophore samples to measure pathogen inhibition, and recorded the dry weight of mycelium at the end of the cultivation period. We compared the effects of a JK-SH007-siderophore solution, a JK-SH007 bacterial re-suspension, and a standard siderophore, Deferroamine B solution (DFOB) on plant growth (seed germination, cucumber seedling growth and tomato fruiting).【Result】Compared to DFOB, the JK-SH007-siderophore sample was more effective at inhibiting fungal growth. The pathogenic fungi were inhibited by (89±0.9)%, (76±0.6)% and (90±0.7)%, forC. chrysosperma, P. macrospora and F. aesculin, respectively. Compared to the JK-SH007 re-suspension, the JK-SH007-siderophore solution resulted in better seed germination and higher seedling vigor; however, there were no significant differences for cucumber seedling growth or tomato fruiting. 【Conclusion】We applied a pure siderophore sample, extracted and purified using chromatography, to plants, and compared this with a bacterial re-suspension sample and a standard commercial product. The pure siderophore sample strongly promoted plant growth and the application of a pure siderophore solution can achieve better anti-fungal effects than DFOB, a result which should inform future commercial development of JK-SH007 as a bio-fertilizer.