曹娜 祝文博 黄麒 刘雪峰

摘 要：用平板对峙法研究贝莱斯芽胞杆菌（Bacillus velezensis）和甲基营养型芽孢杆菌（B. methylotrophicus）对云杉梢枯病病原菌寄生小穴壳（Dothiorella gregaria）的抑菌活性，测定2种拮抗菌的生长曲线和不同培养时间、不同体积分数的发酵液抑菌活性及其稳定性，通过光学显微镜研究抑菌机理。结果表明，2种拮抗菌对云杉梢枯病病原菌均有较强的抑制作用，抑菌率分别为57.50%、56.67%。贝莱斯芽胞杆菌发酵液0～12 h对病原菌菌丝体抑菌率几乎为0;24 h抑菌率达到最大56.52%;24～72 h，抑菌率处于43.48%～47.83%。甲基营养型芽孢杆菌发酵液0～12 h对病原菌菌丝体抑菌率几乎为0;24 h抑菌率达到最大52.17%;24～60 h，抑菌率处于47.83%～52.17%;60～72 h，抑菌率有所下降，抑菌率最低为43.48%。2种拮抗菌发酵液的抑菌活性随着体积分数的升高而上升。2种无菌滤液对温度不敏感，经不同酸碱度处理后抑菌活性下降。通过显微镜观察，2种拮抗菌发酵液能使病原菌菌丝发生变粗彭大、表面粗糙等形态变化。

关键词：贝莱斯芽胞杆菌;甲基营养型芽孢杆菌;青海云杉;云杉梢枯病;抑菌活性

中图分类号：S763.15    文献标识码：A   文章编号：1006-8023（2021）03-0072-07

Abstract：The plate confrontation method was used to study the antibacterial activity of Bacillus velezensis and B. methylotrophicus against Dothiorella gregaria， and the grow curve of two kinds of antagonistic bacteria and the antibacterial activity of different incubation time and different concentration were measured. and antibacterial mechanism was studied by optical microscope. The results showed that two kinds of antagonistic bacteria had significant inhibition effect against D. gregaria with the antibacterial rate of 57.50% and 56.67%， respectively. The antibacterial rate of sterile culture filtrate of B. velezensis was nearly 0 from 0 to 12 h. The maximum antibacterial rate was 56.52% at 24 h， and the antibacterial rate was 43.48%-47.83% in 24-72 h. The antibacterial rate of sterile culture filtrate of B. methylotrophicus was nearly 0 from 0 to 12 h. The maximum antibacterial rate was 52.17% at 24 h， and the antibacterial rate was 47.83%-52.17% in 24-60 h. In 60-72 h， the antibacterial rate decreased， and the lowest was 43.48%. The antibacterial activity of two kinds of antagonistic bacteria sterile culture filtrate increased with the increase of the volume fraction. Two kinds of sterile culture filtrate was not sensitive to temperature and the antibacterial activity decreased after different pH treatment. Under the microscope， two kinds of antagonistic bacteria sterile culture filtrate can make hyphae coarsen， bent and enlarged.

Keywords：Bacillus velezensis; B. methylotrophicus; P. crassifolia Kom.; shoot blight of Picea asperata Mast; antibacterial activity

0 引言

青海云杉（Picea crassifolia Kom.）是松科（Pinaceae）云杉屬（Picea）的一种珍贵树种，为乔木，高度可达23 m，是中国特有的树种，主要分布于我国祁连山区、青海、甘肃、宁夏以及内蒙古大青山等海拔1 600～3 800 m的地带[1-5]。该树种木材性质与云杉相似，高大、通直，结构细致易加工，具有极高的观赏价值和经济价值，比如可供建筑、桥梁、家具及木纤维工业原料等用材。

云杉梢枯病病原菌为寄生小穴壳（Dothiorella gregaria），主要侵染青海云杉的嫩梢，导致嫩梢枯死，严重情况会导致整株死亡，给我国青海云杉带来严重的经济损失。……