苹果树腐烂病拮抗菌株的分离、筛选和鉴定

为筛选出对苹果树腐烂病有拮抗效果的生防菌,从内蒙古达茂草原采集土样,利用逐级稀释法分离菌株;以苹果树腐烂病病菌（Cytospora mali）QH2为供试病原菌,采用平板对峙、离体枝条法、抑菌谱,结合耐盐、耐紫外的稳定性测定筛选拮抗菌株,通过形态学、分子生物学和生理生化方法对拮抗菌株进行鉴定。结果表明,从6份土壤样品中分离纯化得到细菌288株、放线菌54株,经筛选得到DM5-29和DM3-18。DM5-29和DM3-18对C. mali QH2的皿内拮抗圈在1 cm以上,在金红和黄太平枝条上的防效分别在64%、77%以上,抑菌谱广,发酵液紫外照射120 min后仍对苹果树腐烂病具有一定的拮抗活性,可分别在5%NaCl与12%NaCl中生长,鉴定确定DM5-29为贝莱斯芽孢杆菌（Bacillus velezensis）,DM3-18为萎缩芽孢杆菌（Bacillus atrophaeus）,2个菌株对苹果树腐烂病均有良好的拮抗效果,抗逆性强、抑菌谱广,有应用潜力。     

内蒙古呼和浩特市杨树腐烂病病原菌鉴定

To identify the pathogens causing poplar stem rot in Hohhot of Inner Mongolia.Tissue isolation method was used to isolate fungi from poplar trees in Hohhot.The pathogenicities were verified based on Koch’s rule,morphological,and molecular biological methods were then used to identify the pathogenic fungi.Eight fungi were isolated,and 3 isolates named YSFL1,YSFL3 and YSFL4-2 were found to cause the typical canker symptoms.According to the colony characteristics and sporogenetic morphology,ITS and β-tubulin sequences,they were identified as Cryptosphaeria pullmanensis (YSFL1) and Cytospora chrysosperma (YSFL3,YSFL4-2).This study proved that the pathogens of poplar canker in Hohhot area belonged to C.pullmanensis and C.chrysosperma.This result enriched the diversity of poplar canker pathogens in China,and laid a foundation for the prevention and identification of poplar pathogens in Inner Mongolia.