近缘毛壳菌生防菌株LB-1对几种常见植物病原真菌的拮抗作用及其生长适应性分析
Antagonistic effects against several plant pathogenic fungi and the growth adaptability of a Chaetomium subaffine biocontrol strain LB-1

为检测近缘毛壳菌Chaetomium subaffine菌株LB-1的生防效果及其生长适应性，采用平板对峙培养法、含毒培养基法和菌落直径法测定其对6种常见植物病原真菌的拮抗作用，分析其生长的温度、致死温度、光照、pH范围和对干旱胁迫、盐胁迫的抗耐性。结果表明，菌株LB-1对供试的玉米大斑病菌、西瓜枯萎病菌、番茄灰霉病菌、玉米小斑病菌、马铃薯早疫病菌和马铃薯晚疫病菌均具有拮抗作用，PDA平板对峙培养抑制率分别为63.38%、60.59%、60.05%、52.53%、50.46%和44.10%。菌株LB-1的培养液对6种供试病原菌菌落扩展也有显著抑制作用，而且供试病原菌在含菌株LB-1培养液的PDA平板上形成的菌落瘠薄稀疏，菌丝层溶解明显，其中对玉米大斑病菌抑制作用最强，抑制率为30.45%，对马铃薯晚疫病菌抑制作用最弱，抑制率为12.33%。菌株LB-1生长的温度范围为4~37℃，最适温度为25℃，致死温度为60℃；pH范围为5~13，pH 7时生长最好；持续光照对菌株LB-1生长具有显著抑制作用。当PDA平板中PEG 6000含量低于25%，NaCl含量低于1 mol/L时，菌株LB-1均能够较好地生长。表明菌株LB-1是1株具有广谱抑菌特性的生防近缘毛壳菌，对光照、温度、pH有很好的适应性，对干旱及盐胁迫有极强的抗耐性。
To identify the biocontrol effect and the growth adaptability of the Chaetomium subaffine strain LB-1, the antagonistic effects of strain LB-1 against six common plant pathogenic fungi were determined and the influences of temperature, the lethal temperature, light, pH, drought stress and salt stress on the growth of strain LB-1 were analyzed by using dual culture assay, poison plate assay and colony diameter assay. The results showed that strain LB-1 had good antagonistic effects on the growth of Exserohilum turcicum, Fusarium oxysporum f. sp. niveum, Botrytis cinerea, Bipolaris maydis, Alternaria solani and Phytophthora infestans, with an inhibitory rate of 63.38%, 60.59%, 60.05%, 52.53%, 50.46% and 44.10%, respectively. Culture broth of strain LB-1 had significant inhibitory effects on the six fungi tested, and scattered colonies with obvious subiculum dissolution of the tested pathogenic fungi were also found on PDA plates supplemented with culture broth of strain LB-1. The inhibitory rate of strain LB-1 to E. turcicum was the highest (30.45%), and the lowest inhibitory rate (12.33%) was observed in P. infestans. The growth temperature range of strain LB-1 was 4-37℃, and the optimal temperature was 25℃ and the lethal temperature was 60℃; the pH range for the growth of strain LB-1 was 5-13 and the optimal pH was 7; continuous lighting could suppress the growth of strain LB-1 significantly. Strain LB-1 could grow well on PDA plates with PEG 6000 below 25% and NaCl below 1 mol/L, respectively. These results indicated that strain LB-1 had broad antifungal spectrum and good adaptability to light, temperature and pH, and strong resistance to drought stress and salt stress.