小麦赤霉病拮抗菌株筛选及其抑制作用研究

Screening of antagonistic strain against Fusarium head blight and its inhibition efficiency

从高寒草甸野牦牛牛粪中分离得到细菌菌株27株。采用平板对峙法筛选小麦赤霉病高效拮抗菌株,研究其对病原菌禾谷镰刀菌(Fusarium gramminearum)的抑制作用。结果表明,筛选得到的8株小麦赤霉病拮抗中,以菌株LM3403拮抗能力最佳,抑菌带宽(13.2±0.8)mm。通过形态观察、生理生化特征分析、16S r DNA序列分析和gyr B基因序列分析,将其鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。研究发现,菌株LM3403可明显抑制禾谷镰刀菌菌丝体生长和分生孢子萌发,使病菌的菌丝体畸形、细胞膜损伤。该菌株还具有合成surfactin、iturin、fengycin 3种抗菌脂肽的能力。

The research aimed to obtain effective antagonistic strain towards Fusarium head blight （FHB） as well as its inhibition effect against Fusarium gramminearum （FG）. 27 bacterial isolates were isolated from wild yak dung inhabited in alpine steppe of Qinghai-Tibetan Plateau by dilution method, and 8 antagonistic strains against FHB were obtained by antagonistic cultivation. Strain LM3403 was found to have the largest zone of inhibition （13.2±0.8） against FG, which was identified as Bacillus amyloliquefaciens by morphologic observation, biochemical characteristic analysis and sequence analysis of 16S rDNA and gyrB gene. Strain LM3403 could strongly inhibit the hyphal growth and the conidiospore germination of FG,possibly through the processes such as deformation of mycelia, membrane damage of mycelial and conidiospore. Furthermore, strain LM3403 contained three antimicrobial, peptide synthetase genes including Surfactin, Iturin and Fengycin. Therefore, strain LM3403 had great potential to be a bio-control agent against FHB.