大豆毛口壳叶斑病菌产毒素的研究

 针对目前生产上新发现的大豆毛口壳叶斑病菌（Aristastoma sp.）产生的毒素进行了研究。该病菌的Czapek培养液经乙酸乙酯萃取可获得毒素粗提物。通过对该菌产毒条件的研究表明，pH 7的改良Richard培养液产生毒素生物活性最强，培养温度25℃、黑暗条件下持续振荡培养20 d最有利于该病菌毒素的产生。毒素活性测定表明，毒素对大豆叶片产生与病菌作用相同的褪绿症状，对种子胚根生长有抑制作用，对幼苗有致萎作用，说明毒素是大豆毛口壳叶斑病病菌侵染过程中的主要致病因子。

Conditions of producing toxin by soybean leaf spot fungus Aristastoma sp.

Aristastoma sp. is the pathogenic agent of soybean leaf spot disease, which has recently been found in China. To understand optimum conditions for toxin production, crude soybean Aristastoma toxin (SAT) was extracted from various culture filtrates using ethyl acetate. The results showed that the optimum conditions for SAT production were: Richard medium, pH 7, 25℃, dark, shaking culture for 20 days. Bioactivity tests showed that SAT was able to cause typical symptoms of soybean leave spot disease. Also, the SAT caused soybean seedings wilting death and inhibited seed radicle enlongation. The results suggested that the SAT might play an important role during plant being infected by Aristastoma sp..