烟草黑胫病拮抗菌的筛选、鉴定和防病潜力

Screening, identification, biocontrol potential evaluation of strains against tobacco black shank

通过稀释分离法从黔南烟区采集的健康烟草根际土壤中共分离获得73株根际细菌。采用平板对峙培养法初步研究了73株根际细菌对烟草黑胫病菌的抑制作用,从中筛选出5株对黑胫病菌具有较强拮抗作用的根际细菌XPGJ05、YWGJ07、LSGJ04、WAGJ07和LLGJ04。对峙培养试验中,XPGJ05、YWGJ07、LSGJ04、WAGJ07和LLGJ04对黑胫病菌菌丝生长的相对抑制率分别为52.7%、51.8%、53.9%、51.2%和59.5%;代谢液抑菌试验中,XPGJ05、YWGJ07、LSGJ04、WAGJ07和LLGJ04的相对抑制率分别为71.9%、78.3%、68.7%、69.2%和64.3%。田间防效试验中,菌株YWGJ07对烟草黑胫病的防治效果明显高于对照杀菌剂甲霜·锰锌WP和生防菌剂,表明根际细菌YWGJ07具有潜在的应用价值。经16SrDNA序列分析,菌株YWGJ07被初步鉴定为芽孢杆菌属(Bacillus sp.)。

Seventy-three rhizosphere bacteria were isolated from the rhizosphere soil of healthy tobacco collected from Qiannan tobacco growing area by dilution method. Dual culture method was used to study the inhibition of 73 strains on the Phytophthora parasitica var. nicotianae . The results showed that XPGJ05, YWGJ07, LSGJ04, WAGJ07 and LLGJ04 had strong antagonistic effect against P. parasitica var. nicotianae . The mycelial growth inhibition rates of XPGJ05, YWGJ07, LSGJ04, WAGJ07 and LLGJ04 were 52.7%, 51.8%, 53.9%, 51.2% and 59.5% with dual culture method, respectively. In metabolic liquid test, the mycelial growth inhibition rates were 71.9%, 78.3%, 68.7%, 69.2% and 64.3%, respectively. In the field experiment, the control effect on tobacco black shank of YWGJ07 was significantly higher than the control fungicide metalaxyl mancozeb and biocontrol agent. It is showed that YWGJ07 has potential application value. YWGJ07 was identified as Bacillus sp. by 16S rDNA sequence analysis.