木霉菌株T-C7的形态鉴定及其ITS序列分析

摘要

为探求具有抑制串珠镰孢菌活性的木霉菌株，在玉米苗期根腐病发病田块采集土样，经过分离、形态学显微观察后，再根据培养性状和形态特征进行 rDNA-ITS序列分析和邻接法同源性比对等判定木霉菌株种类。结果表明：T-C7显微观察菌落初期白色，菌丝体呈柔毛状，菌落中间有明显产孢区，由黄绿色逐渐转化为绿色，背面无色或者略黄。孢子梗丛束稀疏，环状排列。主分枝呈树状分枝，常2～3个一组，成直角伸出。瓶梗短，基部细，中间膨大，顶部变细，常2～5个轮生。分生孢子呈球形，倒卵形或短椭球形，大小为2．1～3．2μm ×2．3～4．0μm，菌株形态与哈茨木霉吻合。ITS 区序列大小约为570 bp，与AF443928．1ITS区序列的置信度为86，亲缘关系最近。因此，判定 T-C7菌株为哈茨木霉（Trichoderma harzianum）。%In order to explore Trichoderma strains inhibiting Fusarium moniliforme activity,soil samples were collected in maize field with root rot occurred in seedling stage, and the species of Trichoderma strains were identified by adjacent method according to isolation,morphology observation, incubation traits,morphological characteristics and rDNA-ITS sequence analysis.Results:T-C7 was of white colony in initial stage,flocculent mycelium,obvious spore-producing area in the center of colony, which turned from yellow green to green gradually,the back was colorless or a little yellow.Sporophore was rare with circular permutation.The main branch was dendritic,2~3 as one group in common,and extended at right angles.Short phialide,fine base,expanding center and slim top,2~5 verticillate in common.Conidium was spherical,obovate or spheroidicity,2.1~3.2μm× 2.3~4.0μm in size,the strain form was in accordance with Trichoderma harzianum.ITS sequence was 570 bp,the confidence coefficient was 86 with AF443928.1ITS,indicating the relationship was the closest.Consequently,T-C7 was j udged to be T.harzianum.