小麦茎基腐病生防菌株YB-161的分离鉴定及防效测定

Isolation, identification and control efficiency of biocontrol strain YB-161 against wheat crown rot

为筛选防治小麦茎基腐病的高效生防菌株,采用稀释涂布法从小麦茎基腐病病土中分离细菌,以假禾谷镰孢Fusarium pseudograminearum为靶标菌,通过平板对峙培养法和室内盆栽试验筛选优良菌株并测定其田间防治效果,分析优良菌株发酵滤液对假禾谷镰孢的抑菌能力,并结合形态特征、Biolog微生物自动鉴定系统和gyrA序列分析对其进行种类鉴定,以及测定该菌株的抑菌谱。结果表明,10份供试土样中共分离到98株细菌,对假禾谷镰孢的菌丝生长抑制率超过40.00%的菌株有14株,其中菌株YB-161对假禾谷镰孢的菌丝生长抑制率最高,达63.50%。室内盆栽试验结果显示,菌株YB-161处理小麦的病情指数最低,为31.40,对小麦茎基腐病的防治效果最好,为68.15%,其对小麦也表现出较好的促生作用。田间调查结果显示,菌株YB-161菌液拌种处理对小麦茎基腐病的田间防治效果高于52.35%,并对小麦具有一定的增产作用。菌株YB-161的发酵滤液5倍稀释液和10倍稀释液对假禾谷镰孢的菌落抑制率分别达66.67%和44.33%,该菌株被鉴定为解淀粉芽胞杆菌Bacillus amyloliquefaciens。此外,菌株YB-161对辣椒炭疽病菌Colletotrichum capisci、烟草疫霉病菌Phytophthora parasitica等5种植物病原真菌均有较好的拮抗作用。表明生防菌株YB-161对绿色防控小麦茎基腐病具有良好的开发利用潜能。

To screen effective candidate biocontrol agents against wheat crown rot caused by Fusarium pseudograminearum, bacteria were isolated from the diseased soil using the dilution separation method.After the initial screening with confrontation culture and indoor pot test, the control effect of the strain on wheat crown rot was analyzed under field conditions and the antimicrobial ability of fermentation filtrate of the strain was determined. The strain was identified according to morphological characteristics, Biolog microbial identification system and gyrA sequence analysis. In addition, its antimicrobial spectrum was determined. The results showed that 98 strains were isolated from ten soil samples,among which 14 strains significantly inhibited the mycelial growth of F. pseudograminearum with an inhibition rate over 40.00%. Among them, the strain YB-161 had the highest inhibition rate(63.50%).The indoor pot tests showed that the disease index of wheat treated with strain YB-161 was the lowest(31.40), with the highest control efficiency(68.15%), and strain YB-161 could promote the growth of wheat. The results of field experiments indicated that the control efficiency of strain YB-161 on wheat crown rot was higher than 52.35%, concurrently increasing wheat yield. The colony inhibition rates of five-fold dilution and ten-fold dilution of strain YB-161 fermentation filtrate against F. pseudograminearum were 66.67% and 44.33%, respectively. The strain YB-161 was identified as Bacillus amyloliquefaciens. In addition, strain YB-161 showed a strong antagonistic effect on five species of plant pathogens, such as Colletotrichum capisci and Phytophthora parasitica. The results indicated that the biocontrol strain YB-161 had a great potential for green control of wheat crown rot.