中文摘要：

【目的】分离获得对果树真菌病害[苹果轮纹病（Botryospuaeria dothidea）、苹果斑点落叶病（Alternaria alternaria）、葡萄炭疽病（Colletotrichum gloeosporioides）、葡萄白腐病（Coniella diplodiella）和葡萄霜霉病（Plasmopara viticola）]具有明显拮抗作用的菌株,初步研究其作用机制,为果树真菌病害的生物防治提供潜在的材料菌株。【方法】从不同植物上分离内生菌,采用平板对峙法、菌落生长速率法及叶盘法等试验筛选拮抗菌;根据菌株的形态、生理生化特征、16S rDNA序列分析、gyrA基因序列分析等对其进行鉴定;通过测定拮抗菌发酵液对温度、pH值的敏感度分析拮抗物质的稳定性;通过测定拮抗菌发酵液对菌丝的影响,初步分析其拮抗机制。【结果】从不同植物根、茎、叶中共分离得到58株细菌,其中编号为YTB1407的细菌菌株对上述5种植物病原真菌有较好的拮抗作用,经鉴定该菌株为解淀粉芽孢杆菌,且该菌株发酵液的拮抗活性在温度为20～100℃、pH为2.0～10.0,比较稳定。经该菌株发酵液处理后的病原菌菌丝畸形。【结论】该拮抗菌株为Bacillus amyloliquefaciens;温度和pH值对该菌株拮抗物质活性影响不大;该拮抗菌株可以通过影响病原菌菌丝正常生长发挥其拮抗作用。

英文摘要：

[Objective]Apple and grape are two of the most important fruits in China.The fungal diseases such as ring rot and Altermaria leaf spot in apple,and bitter rot,white rot and downy mildew in grape seriously affect the productivity and quality of the crops.To control the diseases at reduced chemical pesticide application,the antagonistic bacterium strains with strong inhibitory activity against fungal pathogens in fruit trees（e.g.Botryospuaeria dothidea and Alternaria alternaria in apple,and Colletotrichum gloeosporioides,Coniella diplodiella and Plasmopara viticola in grape） were isolated.This research provides potential materials for the biological control of fungal pathogens in fruit trees.[Methods]Endophytes were isolated and cultivated from the leaves,stems,roots and fruits of different plants（grape,apple,pear,blueberry,apricot,peach,cherry and American ginseng）.We selected colonies with different morphology and colors as the tested strains.Mycelial plugs of the pathogenic fungus（B.dothidea,A.alternaria,C.gloeosporioides and C.diplodiella） about 6 mm in diameter were placed on the PDA medium plate,then endophytes for test were placed at four equidistant points around the pathogenic fungus.The inhibition zones were measured after the plates were incubated at 28 ℃ in dark for 4 to 7 days.The antagonistic strains which generated inhibition zones ≥7.0 mm were selected for further tests.The antagonistic strains were cultured in100 mL beef extract peptone liquid medium at 25 ℃,which was rotated at 200 r·min～（-1） for 48 h.The bacterial broth was centrifuged at 5 000 r·min～（-1） for 10 min and the supernatant was collected as fermentation liquor.Healthy grape leaves were soaked in the fermentation liquor diluted 20 times for 2 h and then allowed to dry out naturally.The effect of antagonistic strains in controlling Plasmopara viticola was tested according to Liu Xu＇s method.The antagonistic strain YTB1407 was gram stained,spore stained,flagella stained,catalase tested,aerobic and anaero