大豆内生细菌的分离及根腐病拮抗菌的筛选鉴定

Isolation and Characterization of Antifungal Endophytic Bacteria from Soybean

摘要:

内生细菌存在于健康植物体内, 一些内生细菌具有促生长、抗病和固氮等生物学功能。本项研究采用化学药剂表面灭菌方法从黑龙江省大豆品种合丰25的根、茎、叶和种子中分离到大量内生细菌, 其种群数量在根部最多, 为3.4×103 CFU/g, 在叶部次之, 为2.8×103 CFU/g, 在茎部和种子中最少, 为2.9×102 CFU/g 和 1.4×102 CFU/g。从121株内生细菌中筛选到31株对大豆根腐病菌Fusarium oxysporum f. sp. soybean具有较强抑制作用的拮抗内生细菌, 其中菌株TF28抑菌谱广, 抑菌率高, 对不同植物的病原菌F. oxysporum 的抑菌率为80.2%~96.7%。经形态、生理生化和16S rRNA鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。

Abstract:

Endophytic bacteria reside in most healthy plants; it can not be easily influenced by outer environment. Some endophytic bacteria are beneficial to host plants, such as growth promotion, disease prevention and nitrogen fixation etc. Therefore, endophytic bacteria are the potential microbial fungicides, it may be widely applied. In this study, endophytic bacteria were isolated from soybean cultivar Hefeng 25 that was a main soybean cultivar in Heilongjiang province, China. The results indicated that the density of endophytic bacteria varied in different tissues of the plant. It was 3.4×103 CFU/g in roots, 2.8×103 CFU/g in leaves, 2.9×102 CFU/g in stems and 1.4×102 CFU/g in seeds. The activity of 121 strains against Fusarium oxysporum f. sp. soybean, caused soybean root rot, were assayed. 25.6% of them showed antagonistic activity against F. oxysporum f. sp. soybean. One of them, strain TF28 isolated from soybean roots could inhibit the growth of many fungal pathogens. The inhibitory rates against F. oxysporum from different plant species were 80.2%-96.7%. Based on the morphological, physiological and biochemical characteristics as well as the sequence of 16S rRNA, strain TF28 was identified as Bacillus amyloliquefaciens.