飞机草链格孢毒素的培养条件、分离及活性测定

[目的]对链格孢菌株LGB 100401的产毒培养条件及毒素的除草活性进行评估,为飞机草的生物防治提供理论依据.[方法]以从海南田间染病的飞机草上分离到的链格孢菌LGB 100401菌株为材料,采用以生物测定为导向的乙酸乙酯萃取和硅胶柱层析等方法对LGB 100401菌株所产毒素进行分离纯化及产毒条件研究,并采用离体叶片针刺接种法测定38种植物对LGB 100401菌株所产毒素的敏感性.[结果]LGB 100401菌株可产生毒素并导致飞机草叶片枯死,最适产毒条件为25℃、pH 4~6、光暗交替培养15d.LGB 100401菌株分泌的毒素对供试38植物具有选择毒性,其中,供试杂草对链格孢粗毒素不敏感(NS)的有17种、稍敏感(LS)4种、敏感(MS)7种、极敏感(SS)4种,表现为极敏感的杂草为飞机草、马唐、羽芒菊和赛葵;供试的6种作物中只有水稻表现为敏感(MS),其他5种作物不敏感或表现轻微症状.[结论]飞机草链格孢毒素对飞机草具有较高的抑制活性,具有较高的生防潜力.

Culture conditions,separation and activity determination of Alternaria alternata toxin from Chromolaena odorata

[Objective]The research evaluated toxin production cultural conditions for Alternaria alternata strain LGB100401 and herbicidal activity of the toxin,in order to provide theoretical basis for biological control of Chromolaena odorata.[Method]A.alternata strain LGB100401 isolated from infected C.odorata in field in Hainan was taken as material.The bioassay-guided ethyl acetate extract and silica gel column chromatographic separation were used to isolate,purify the toxin and research the toxin production conditions.Sensitivity of 38 species of plants to the toxin was tested using detached leaf puncture inoculation method.[Result]Results showed that LGB100401 could produce toxins which led to necrosis of C.odorata leaf.The optimal cultural conditions for producing toxin were temperature 25 ℃,pH 4-6,cultured period 15 d under alternation of light and dark.The toxin had selective toxicity towards the 38 species of plants.Sixteen species were not sensitive (NS) to the toxin,four species were slightly sensitive (LS),eight species were sensitive (MS) and four species were very sensitive(SS).The four species which were very sensitive were C.odorata,Digitaria sanguinalis,Tridax procumbent and Malvastrum coromandelianum.Among the six tested crops,only rice was sensitive(MS) to the toxin,the rest five crops were not sensitive or only showed slight symptom.[Conclusion]Alternaria alternata toxin from C.odorata has strong inhibitory effect on C.odorata.It may be useful for biological control of C.odorata.