Melanin biosynthesis and its biological function as heat persistence in plantpathogens and other fungi

植物病原体和其他真菌中黑色素的生物合成及其作为耐热性的生物学功能

• 批准号: 12660049
• 负责人: FUJIMURA Makoto
• 金额: $ 1.92万
• 依托单位: TOYO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12660049/
• 关键词: melanin; Pyricularia; polyketide synthase; Neurospora; sexual cycle; 耐熱性; イネいもち病菌; ポリケタイド合成酵素; Neurospora; Verticillium

Melanin biosynthesis inhibitors, such as carpropamid and diclocymet, affected conidial formation in Pyricularia oryzae. In addition, the conidia on the medium containing fungicides increased the sensitivity to heat treatment. Reduced heat persistence induced by fungicides was not observed in fungicide resistant isolates, suggesting correlation between melanization and heat persistence. In Neurospora crassa, black pigment develops in sexual organs such as perithecia and ascospore, and ascospore showed high resistance to heat treatment. On the other hand, ascospore of the per-1 mutant, melanin deficient strain, was sensitive to heat treatment. The wild-type strain treated by tricyclazole accumulated 2-HJ, a shunt product of DHN-melanm. The DHN-melanin synthesis genes, such as PKS, SDH, and HNR, were clones and characterized. The per-1 mutant strain transformed with the wild-type PKSgene recovered the ability of melanin biosynthesis and heat resistance. The mutation within the PKSgene of the per-1 mutant strain was identified as ^<210>arg to stop codon. The transcription of melanin biosynthesis genes was induced by fertilization not by nutrient starvation in sexual cycle of N.crassa.

黑色素生物合成抑制剂环丙酰菌胺和双孢霉素对梨孢霉分生孢子的形成有一定的影响。此外，分生孢子在含杀菌剂的培养基上生长，增加了对热处理的敏感性。在杀菌剂抗性菌株中没有观察到杀菌剂诱导的热持久性降低，表明黑化和热持久性之间存在相关性。粗糙脉孢菌的性器官如子囊孢子和子囊孢子中产生黑色色素，并且子囊孢子对热处理表现出很高的抗性。另一方面，黑色素缺乏型菌株per-1的子囊孢子对热处理敏感。用三环唑处理的野生型菌株积累了2-HJ，这是DHN-黑色素的分流产物。对DHN-黑色素合成基因PKS、SDH、HNR进行了克隆和鉴定。转野生型PKS基因的突变株per-1恢复了黑色素合成能力和耐热性。per-1突变株的PKS基因内的突变被鉴定为^<210>arg至终止密码子。粗厚脉金藻性周期中黑色素合成基因的转录受受精诱导，而非营养饥饿诱导。