Mycoparasitism of Gliocladium isolates in China  

作　　者：ZHANGYong-hua MAGui-zhen GAOHui-lan LIShi-dong 

机构地区：[1]Soil-bornediseasesLab,BiologicalControlInst.,ChineseAcademyofAgri.Sci.,Beijing100081,China

出　　处：《浙江大学学报（农业与生命科学版）》2004年第4期412-413,共2页Journal of Zhejiang University:Agriculture and Life Sciences

摘　　要：During an investigation of mycoparasitic fungi on sclerotia of Sclerotinia sclerotiorum in China, Gliocladium species was consistently encountered and isolated from natural soils collected over the country. Colonization frequencies on sclerotia of S. sclerotiorum by the fungi ranged from 40% to 100% when the sclerotia were introduced into soils and coincubated at 22-24 ℃ for 4 weeks. Identification showed that G. roseum, G. virens and G. catenulatum were the dominant species among the 300 isolates gained. Molecular taxonomy of some Gliocladium isolates analysed by rDNA ITS sequence used ITS1 and ITS4 as primers was demonstrated to be identical with morphological classification. Reinoculation tests by placing surface-sterilized sclerotia onto colony of Gliocladium isolates for 7 days and then surface-sterilized again resulted in 100% sclerotia colonized. Dipping sclerotia with spores suspension of isolates for 5 min and incubated the sclerotia in Petri dishes at 25 ℃ for 24 h resulted in infection of the sclerotia. Microscopic observations indicated that Gliocladium isolates grew along the host hyphae, coiled around, formed appressorium-like structures, penetrated and degraded hyphae of S. sclerotiorum when dual-cultured in slides. Paraffin-section showed that sclerotial tissue collapsed when infected by Gliocladium isolates. Host range test demonstrated that the isolates suppressed hyphal growth of several plant pathogenic fungi, including S. sclerotiorum, Botrytis cinerea, Fusarium oxysporum, Alternaria tenuis, and Rhizoctonia solani. Activities of fungal cell wall degrading enzymes in cultural filtrates and parasitized sclerotia were detected. Results indicated that chitinase and glucanase were important factors involved in the mycoparasitism. A 51 kDa chitinase was isolated and purified from G. catenulatum HL-1-1 culture filtrate. A part of amino acid sequences of the enzyme has been analysed. It was found to have a high homogeneity to chitinase A from Stenotrophomonas maltophilia, while no homogeneity to During an investigation of mycoparasitic fungi on sclerotia of Sclerotinia sclerotiorum in China, Gliocladium species was consistently encountered and isolated from natural soils collected over the country. Colonization frequencies on sclerotia of S. sclerotiorum by the fungi ranged from 40% to 100% when the sclerotia were introduced into soils and coincubated at 22-24 ℃ for 4 weeks. Identification showed that G. roseum, G. virens and G. catenulatum were the dominant species among the 300 isolates gained. Molecular taxonomy of some Gliocladium isolates analysed by rDNA ITS sequence used ITS1 and ITS4 as primers was demonstrated to be identical with morphological classification. Reinoculation tests by placing surface-sterilized sclerotia onto colony of Gliocladium isolates for 7 days and then surface-sterilized again resulted in 100% sclerotia colonized. Dipping sclerotia with spores suspension of isolates for 5 min and incubated the sclerotia in Petri dishes at 25 ℃ for 24 h resulted in infection of the sclerotia. Microscopic observations indicated that Gliocladium isolates grew along the host hyphae, coiled around, formed appressorium-like structures, penetrated and degraded hyphae of S. sclerotiorum when dual-cultured in slides. Paraffin-section showed that sclerotial tissue collapsed when infected by Gliocladium isolates. Host range test demonstrated that the isolates suppressed hyphal growth of several plant pathogenic fungi, including S. sclerotiorum, Botrytis cinerea, Fusarium oxysporum, Alternaria tenuis, and Rhizoctonia solani. Activities of fungal cell wall degrading enzymes in cultural filtrates and parasitized sclerotia were detected. Results indicated that chitinase and glucanase were important factors involved in the mycoparasitism. A 51 kDa chitinase was isolated and purified from G. catenulatum HL-1-1 culture filtrate. A part of amino acid sequences of the enzyme has been analysed. It was found to have a high homogeneity to chitinase A from Stenotrophomonas maltoph

关 键 词：真菌寄生现象 粘帚霉属 分离 中国 真菌 核盘菌属 几丁质酶 生物学特性 

分 类 号：Q949.32[生物学—植物学]