一种捕食线虫性真菌的鉴定及生物学特性分析

Identification and biological characterization of a nematode-trapping fungus

摘要:

【背景】松材线虫病是一种对林木危害严重的森林病害，而捕食线虫性真菌可以利用其捕食器官捕食松材线虫，从而实现对松材线虫病的有效防治。【目的】鉴定分离出一株捕食线虫性真菌并探究其最适生长和产孢条件，为松材线虫的生物防治提供一定的参考依据。【方法】使用ITS2、RPB2和TEF1-α序列对该菌株进行分子生物学鉴定，同时结合其形态特征确定其具体所属种属。观察该菌株在不同温度、pH和营养条件下的生长状况及变化规律，明确其具体的生物学特性。【结果】形态学鉴定结果及分子生物学鉴定结果表明该捕食线虫性真菌为强力节丛孢(Arthrobotrys robusta)。该菌株最适生长和产孢条件有所不同。最适生长条件为28 ℃、pH 10.0-11.0、玉米粉琼脂(corn meal agar, CMA)培养基、碳源为淀粉、氮源为KNO₃。最适产孢条件为30 ℃、pH 8.0、马铃薯葡萄糖琼脂(potato dextrose agar, PDA)培养基、碳源为淀粉、氮源为蛋白胨。【结论】该捕食线虫性真菌为强力节丛孢，对不同环境具有较强的适应能力，在各种环境下除部分极端环境外均能良好生长，对松材线虫具有良好的生防潜力。

Abstract:

[Background] Pine wilt disease is a serious disease that endangers forest trees. Nematode-trapping fungi can use their trapping organs to prey on Bursaphelenchus xylophilus, thus achieving effective control of pine wilt disease. [Objective] To isolate and identify a nematode-trapping fungus and explore its optimum growth and sporulation conditions, thus providing a reference for the biocontrol of B. xylophilus. [Methods] The strain was identified based on the ITS2, RPB2, and TEF1-α sequences and morphological characteristics. The growth status and variations of the strain under different temperature, pH, and nutrient conditions were observed for biological characterization of this strain. [Results] The nematode-trapping fungus was identified as Arthrobotrys robusta. The optimum growth and sporulation conditions of the strain were different. The optimum growth conditions were 28 ℃, pH 10.0-11.0, corn meal agar (CMA) medium, starch as the carbon source and KNO₃ as the nitrogen source. The optimum sporulation conditions were 30 ℃, pH 8.0, potato dextrose agar (PDA) medium, starch as the carbon source and peptone as the nitrogen source. [Conclusion] The nematode-trapping fungus A. robusta has strong adaptability to the environment. It can grow well in various environments except some extreme environments and demonstrates biocontrol potential against B. xylophilus.