Evolutional origin of the conditionally dispensable chromosomes controlling plant infection in Alternaria alternata pathogens

2014 Fiscal Year Final Research Report

• Project/Area Number: 23248007
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Plant pathology
• Research Institution: Nagoya University
• Principal Investigator: TSUGE Takashi 名古屋大学, 生命農学研究科, 教授 (30192644)
• Co-Investigator(Kenkyū-buntansha): KODAMA Motoichirou 鳥取大学, 農学部, 教授 (00183343) ; HANADA Kousuke 九州工業大学, 若手研究者フロンティア研究アカデミー, 准教授 (50462718)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: 植物病原糸状菌 / 宿主特異的毒素 / 病原性 / CD染色体 / 寄生性進化 / 遺伝子水平移動

Outline of Final Research Achievements

The CD (Conditionally Dispensable) chromosomes of plant pathogenic fungi are essential for the disease-causing capacity on host plants, but not for growth on media. We analyzed the structure and function of CD chromosomes of three pathogens of Alternaria alternata, which produce host-specific toxins (HSTs) as pathogenicity factors. The CD chromosomes of the three pathogens encode HST biosynthetic gene (TOX) clusters and are essential for their host-specific pathogenicity. The CD chromosomes were found to consist of large syntenic regions and pathogen-specific regions including TOX clusters. This result indicates that the syntenic regions are the core of the original, dispensable chromosome, and that the TOX genes were integrated into the original chromosome. Phylogenetic analysis of TOX genes suggests that a part of TOX genes was obtained from other fungi by horizontal gene transfer.

Free Research Field

植物病理学