Genetic Analysis of Pathogenicity and Host-specific Toxin Production of Alternaria alternata Tomato Pathotype by Protoplast Fusion

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• 作者：SALAMIAH ; Yukitaka FUKUMASA-NAKAI ; Hajime AKAMATSU ; Hiroshi OTANI ; Keisuke KOHMOTO and Motoichiro KODAMA
• 关键词：Key words ; Alternaria alternata ; AAL ; toxin ; protoplast fusion ; tomato.
• 刊名：Journal of General Plant Pathology
• 出版年：2001
• 出版时间：February 2001
• 年：2001
• 卷：67
• 期：1
• 页码：7-14
• 全文大小：1,689 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Pathology
  Agriculture
  Microbiology
  
• 出版者：Springer Japan
• ISSN：1610-739X

文摘

Several pathotypes of Alternaria alternata are known to produce host-specific toxins (HSTs) as agents of pathogenicity or virulence. However, investigations into the genetic controls of HST biosynthesis and pathogenicity of Alternaria pathogens have been limited by the lack of a sexual stage in the life cycle of these pathogens. We report here the development of a protoplast fusion system and its use for genetic analysis of HST production and specific pathogenicity of the tomato pathotype of A. alternata that produces AAL-toxin as a HST. Drug-resistant transformants have been isolated by genetic transformation of nonpathogenic A. alternata (strain O-94) and A. alternata tomato pathotype (strain As-27) with vectors conferring resistance to hygromycin B and geneticin, respectively. Protoplasts of the respective transformants were fused by polyethylene glycol treatment or electrofusion. Fusion products were selected by culturing in the presence of both hygromycin B and geneticin, then confirmed by amplification using a polymerase chain reaction with specific primers to the transforming drug-resistance genes. Stable fusants were purified by successive subcultures on selective medium and single-spore isolation. The resultant stable fusants, probably inter-strain hybrids, had the same pathogenicity and toxin production as the wild-type strain As-27. These results suggest that protoplast fusion has potential applications for genetic analysis of A. alternata pathogens.