栓皮栎叶部炭疽病与褐斑病真菌优势种群及致病性测定

Dominant Populations in Leaf Diseases of Quercus variabilis and Their Pathogenicity Determination

【目的】了解我国4省(河南、陕西、安徽、贵州)7个地区的栓皮栎(Quercus variabilis)叶部病害发生情况及其主要病原菌,促进栓皮栎的保护和病害防控。【方法】采用组织分离法对栓皮栎2种叶部病斑(炭疽病和褐斑病)上的相关真菌进行分离,经形态特征鉴定和rDNA-ITS序列分析鉴定,利用离体叶片接种试验验证分离物的致病性。【结果】从2种叶部病害病斑中分离出了真菌31株,分属3个属:椿启介菌属(Tubakia)、炭疽菌属(Colletotrichum)、间座壳属(Diaporthe),9个种和1个未知种。其中胶孢炭疽菌(C.gloeosporioides)和干孢盾壳椿启介菌(T.dryina)分别为炭疽病和褐斑病的优势种群。接种实验证实,胶孢炭疽菌和干孢盾壳椿启介菌对栓皮栎叶片具有较强致病性。【结论】调查发现了栓皮栎叶部受炭疽病与褐斑病两种病害侵扰,其病原菌分别鉴定为胶孢炭疽菌与干孢盾壳椿启介菌。从病斑中分离鉴定了与病害相关的真菌共9个已知种和1个潜在新种,新种的界定需进一步工作证实。

【Objective】The leaf diseases of Q.variabilis were investigated in seven typical regions,which were selected from four provinces,including Henan,Shaanxi,Anhui and Guizhou.The results would be applied for the prevention and restraint of Q.variabilis diseases.【Methods】Fungi related two leaf spot diseases(anthracnose and brown spot)of Q.variabilis were isolated by tissue isolation methodology.Then the isolated fungi were identified by their morphological characteristics and rDNA-ITS sequence analysis.In addition,the in vitro leaf inoculation was conducted to determine the pathogenicity of the isolates.【Results】31 fungal strains were isolated and identified,which belonged to 9 species and 1 unknown species in 3 genera,including Tubakia,Colletotrichum and Dicarpella.In particular,C.gloeosporioides and T.dryina were dominant fungus populations in isolates from the samples,which were found primary pathogens for anthracnose and brown spot of Q.variabilis,respectively.【Conclusion】Two leaf diseases(anthracnose and brown spot)of Q.variabilis were identified,which were mainly caused by two specific pathogens,C.gloeosporioides and T.dryina Among the ten observed probable pathogenic species,one unknown species was possibly a novel species,which required future identification.