稗草生防菌株NX1的生物学特性及致病性研究

Biological characteristics and pathogenicity of the biocontrol fungal strain NX1 for Echinochloa crusgalli

摘要:

【目的】稗草是我国农田危害最严重的恶性杂草之一，化学除草剂的长期使用导致杂草抗药性上升、环境污染等诸多生态环境问题，因此开发绿色、环境友好的高效除草剂显得十分必要且迫切。【方法】采用常规组织分离法、形态学观察和分子生物学方法鉴定NX1菌株，并采用多元统计分析方法研究NX1菌株的致病性及其影响因素。【结果】经鉴定NX1菌株可能为弯孢属新种(Curvularia sp.)。该病原菌在25−30 、pH为5−11的条件下均能生长和产孢，其中，在pH为9、30 条件下产孢量最高。光照条件虽然不影响菌丝的生长，但连续光照条件有利于NX1菌株产孢。NX1菌株在不同碳源、氮源条件下都能生长，其中对玉米粉和硝酸钠的利用效果最好。室内生防试验表明，湿度、稗草叶龄、光照时间及孢子浓度均是显著影响NX1菌株致病性的因素，其中湿度是最关键的因素。作物安全性试验表明，该菌株的分生孢子液对水稻、油菜、辣椒和茄安全。【结论】综上所述，菌株NX1对环境和营养条件要求不高，适合工业化生产及田间应用，具有开发成为生物除草剂的潜力。

Abstract:

[Objective] Echinochloa crusgalli is one of the major noxious weeds in China’s farmlands. The long-term use of chemical herbicides has caused eco-environmental problems, such as the enhanced weed resistance and environmental pollution. Therefore, it is urgent to develop environment-friendly high-performance herbicides. [Methods] The strain NX1 was identified by tissue isolation, morphological observation, and molecular biological methods, and its pathogenicity and influencing factors were studied by multivariate statistical analysis. [Results] The strain was probably a new species of Curvularia. It can grow and produce spores at 25-30 and pH 5-11, with the highest sporulation quantity at pH 9 and 30. Although light did not affect the mycelial growth, continuous light was conducive to sporulation of the strain NX1. The strain NX1 can grow with different carbon and nitrogen sources, with the best utilization of corn meal and sodium nitrate. The laboratory biocontrol experiments showed that humidity, leaf age, light duration, and spore concentration significantly affected the pathogenicity of NX1 strain, among which humidity was the key factor. The crop safety test showed that the conidial suspension of the strain was safe to rice, rape, capsicum, and eggplant. [Conclusion] The strain NX1 has low requirements for environmental and nutritional conditions and is suitable for industrial production and field application. Therefore, it has the potential to be developed into a bioherbicide.