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Studies on the infection strategy as the blossom pathogen on the Japanese cedar twig blight

柳枝枯枝病开花病原菌侵染策略的研究

基本信息

批准号：
15580138
负责人：
KUBONO Takanori
金额：
$ 1.92万
依托单位：
Forestry and Forest Products Research Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

The primary infection court for the onset of twig blight of Japanese cedar, Sugi (Cryptomeria japonica), caused by the pathogen Stromatinia cryptomeriae, is the male strobilus. It was hypothesized that the male strobili provide a favorable environment for ascospore germination and hyphal growth. Consequently, the roles of pollen, water-retention and micro-flora in germination of ascospores in the strobili were investigated. In the first 6 hours after ascospores of S. cryptomeriae were released onto various aqueous suspensions of cedar pollen, no ascospore germination occurred in any treatment. However, at 12 hours all ascospores had germinated in all suspensions containing cedar pollen. The levels ascospore germination increased in proportion to the concentration of pollen in the suspension. Whereas a few ascospores germinated in sterilized water free of pollen, no ascospores germinated in the absence of water. The existence of a saccaride and an amino acid was confirmed by the an analytical study of the extracts in Japanese cedar pollen. These results show that water is indispensable in germination of the ascospores and that cedar pollen grains promote the germination. Male strobili at different stages of development were collected from infected trees. Pestalotiopsis sp., Phoma sp. and Cladosporium sp. were most frequently isolated from the immature strobili and appear to be endophytes. The fungi most frequently isolated from mature male strobili were Pestalotiopsis sp., Phoma sp. snd S.cryptomeriae. This observation indicates that the twig blight pathogen is able to coexist with these other fungi however, it is unclear whether they assist in its invasion of the strobili or stand against its invasion (antagonism).

柳杉（Cryptomeria japonica）枝枯病是由柳杉层孔菌（Stromatinia cryptomeriae）引起的，其主要侵染途径是雄球花。推测雄球花为子囊孢子萌发和菌丝生长提供了有利的环境。研究了花粉、水分和微生物区系对子囊孢子萌发的影响。在孢子萌发后的前6小时内，S.将柳杉孢子释放到雪松花粉的各种水性悬浮液上，在任何处理中均未发生子囊孢子萌发。然而，在12小时时，所有子囊孢子在所有含有雪松花粉的悬浮液中都已萌发。子囊孢子萌发率随花粉浓度的增加而增加。在无花粉的无菌水中有少量子囊孢子萌发，而在无水条件下无子囊孢子萌发。通过对日本雪松花粉中提取物的分析研究，证实了糖和氨基酸的存在。这些结果表明，水分对子囊孢子的萌发是必不可少的，雪松花粉粒对子囊孢子的萌发有促进作用。从受感染的树收集不同发育阶段的雄性孢子叶球。拟盘多毛孢属，茎点霉属和枝孢霉属最常从未成熟的孢子叶球中分离出来，似乎是内生菌。从成熟雄球花中分离到的真菌最多的是拟盘多毛孢属，茎点霉和柳杉茎点霉这一观察结果表明，枝枯病病原体能够与这些其他真菌共存，然而，尚不清楚它们是否有助于其对孢子叶球的入侵或抵抗其入侵（拮抗作用）。