东乡野生稻内生细菌Fse32拮抗作物病害真菌及对水稻的促生活性

Antagonism against crop pathogenic fungi and rice growth-promoting potential of endophytic bacteria Fse32 from Dongxiang wild rice (Oryza rufipogon Griff.)

摘要:

【背景】植物种子是植物内生菌筛选的重要原料，从中能够分离得到具有巨大应用价值的内生菌株。【目的】为发掘优良的种子内生细菌资源，对分离自东乡野生稻种子的内生细菌Fse32进行鉴定并研究其抗病原真菌和促生活性。【方法】通过形态学观察、生理生化特征和16S rRNA基因序列分析进行菌种鉴定，采用拮抗试验检测抑制病原真菌的活性，通过促生能力测定试验、水稻种子萌发及盆栽试验评价该菌株的促生效果。【结果】内生细菌Fse32鉴定为唐菖蒲伯克霍尔德氏菌，命名为Burkholderia gladioli Fse32。拮抗试验结果显示，菌株Fse32对禾谷镰孢菌(Fusarium graminearum)、水稻纹枯病菌(Rhizoctonia solani)、核盘菌(Sclerotinia sclerotiorum)、大豆核盘菌(Sclerotinia libertiana)、尖孢镰刀菌(Fusarium oxysporum)和辣椒疫霉病菌(Phytophthora capsici)均有较好的抑制作用，吲哚乙酸(indole-3-acetic acid, IAA)产率为17.95 mg/L，能产铁载体，其A/A_r比值为0.24，溶解无机磷量为339.07 mg/L。种子萌发及盆栽试验结果表明，菌株Fse32能显著促进水稻种子萌发，施用该菌后水稻幼苗株高、根长、干重和总叶绿素含量分别增长7.9%、33.5%、108.9%和68.9%。【结论】Burkholderia gladioli Fse32是一株功能多样且高效的植物内生细菌，具有很好的生物防治及促生应用前景。

Abstract:

[Background] Plant seeds are important raw source for screening endophytic bacteria, from which the strains with great application values can be isolated. [Objective] To explore excellent endophyte resources from seeds, we identified the endophytic bacterial strain Fse32 isolated from the seeds of Dongxiang wild rice (Oryza rufipogon Griff.) and evaluated its resistance to pathogenic fungi and growth-promoting effects. [Methods] The isolated bacteria was identified based on morphological, physiological, and biochemical characteristics and 16S rRNA gene sequence. The antagonistic experiment was carried out to determine the inhibitory activities on pathogenic fungi. The tests of growth promoting ability, rice seed germination and pot experiments were conducted to evaluate the growth-promoting effect of the strain. [Results] Endophytic bacteria Fse32 was identified as Burkholderia gladioli Fse32. The strain exhibited remarkable effectiveness against Fusarium graminearum, Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotinia libertiana, Fusarium oxysporum, and Phytophthora capsici. Furthermore, Fse32 displayed excellen growth-promoting potential, the production of Indoleacetic acid (indole-3-acetic acid, IAA) at a yield of 17.95 mg/L, the capability of producing siderophores, with an A/A_r ratio of 0.24 and the inorganic phosphorus-solubilizing ability of 339.07 mg/L. The results of seed germination and pot experiments showed that strain Fse32 significantly promoted rice seed germination, and increased the plant height, root length, dry weight, and total chlorophyll content of rice seedlings by 7.9%, 33.5%, 108.9%, and 68.9% respectively. [Conclusion] Burkholderia gladioli Fse32 is an endophytic bacterium with diverse functions and high efficiency, demonstrating a promising prospect for biocontrol and growth promotion.