Szentiványi Orsolya, Kiss Levente, Russell John C, Kovács Gábor M, Varga Krisztina, Jankovics Tünde, Lesemann Silke, Xu Xiang-Ming, Jeffries Peter
Plant Protection Institute of the Hungarian Academy of Sciences, PO Box 102, H-1525 Budapest, Hungary.
Mycol Res. 2005 Apr;109(Pt 4):429-38. doi: 10.1017/s0953756204001820.
Pycnidial fungi belonging to the genus Ampelomyces are the most common natural antagonists of powdery mildews worldwide. During a study of the interactions between apple powdery mildew (Podosphaera leucotricha) and Ampelomyces mycoparasites, 52 new Ampelomyces isolates were obtained from P. leucotricha and, in addition, 13 new isolates from other species of the Erysiphaceae in four European countries. Their genetic diversity was screened using single-stranded conformation polymorphism (SSCP) analysis of the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA). For comparison, 24 isolates obtained from genetic resource collections or other sources were included in this study. Based on the ITS-SSCP patterns, the isolates were placed in eight groups. The isolates belonged to two types based on their growth in culture. The faster-growing and the slower-growing isolates were included in different SSCP groups. A phylogenetic analysis of the ITS sequences of representatives of these groups confirmed the results obtained with the SSCP method, and showed that the faster-growing isolates do not belong to Ampelomyces as suggested by earlier studies. All the isolates from P. leucotricha fell into a distinct SSCP group of genetically homogeneous isolates. This suggests that Ampelomyces mycoparasites which occur in apple powdery mildew are slightly different from the other Ampelomyces groups which contain mycoparasites from various powdery mildew species. This may be because the main growth period of Ampelomyces mycoparasites in apple powdery mildew is isolated in time from that of Ampelomyces isolates that occur in other species of the Erysiphaceae. P. leucotricha starts its life-cycle early in the season, usually in March-April, while most powdery mildews are active in the same environments only late in the year.
属于顶孢霉属的分生孢子真菌是全球范围内白粉菌最常见的天然拮抗物。在一项关于苹果白粉病（白叉丝单囊壳菌）与顶孢霉属真菌寄生菌相互作用的研究中，从白叉丝单囊壳菌中获得了52株新的顶孢霉分离株，此外，还从四个欧洲国家的白粉菌科其他物种中获得了13株新分离株。利用核糖体DNA（rDNA）内转录间隔区（ITS）区域的单链构象多态性（SSCP）分析对它们的遗传多样性进行了筛选。为作比较，本研究纳入了从遗传资源库或其他来源获得的24株分离株。根据ITS-SSCP图谱，这些分离株被分为八组。根据它们在培养中的生长情况将分离株分为两种类型。生长较快和生长较慢的分离株被归入不同的SSCP组。对这些组的代表菌株的ITS序列进行系统发育分析，证实了用SSCP方法获得的结果，并表明生长较快的分离株并不像早期研究所暗示的那样属于顶孢霉属。所有来自白叉丝单囊壳菌的分离株都属于一个遗传同质的独特SSCP组。这表明，苹果白粉病中出现的顶孢霉属真菌寄生菌与包含来自各种白粉菌物种寄生菌的其他顶孢霉属组略有不同。这可能是因为苹果白粉病中顶孢霉属真菌寄生菌的主要生长时期在时间上与白粉菌科其他物种中出现的顶孢霉属分离株的生长时期相隔离。白叉丝单囊壳菌在季节早期开始其生命周期，通常在3月至4月，而大多数白粉菌在相同环境中仅在当年晚些时候才活跃。
