Studies on the Molecular Mechanism in Life-cycle Development and Signal Trnnsduction of Aphanomyces cochlioides, a Cause of Spinach Root Rot

1.植物病原卵菌的游动孢子对寄主特有的单一物质具有明显的正趋化性。用生物素偶联叠氮黄酮作为探针，对菠菜根腐病病原菌游动孢子的寄主专一性引诱剂受体进行了研究，在凝胶电泳板上产生了40和70 kDa的膜蛋白。2.利用显微技术研究了卵孢子菌(卵孢菌科)卵孢子虫的生活史中信号转导所引起的事件。从寄主植物和非寄主植物中分离到150株根面细菌，其中5%以上的菌株对植物病原真菌Cochlioidaphanmycescochlioid产生严重的形态变化，真菌生长受到强烈抑制。根据这些结果，我们提出了一种新的有效的方法来寻找防治土壤植物病原菌的生防剂。4.亲游动孢素A(5-羟基-6，7-亚甲基二氧基黄酮)是菠菜根腐病病原菌的寄主特异性游动孢子引诱剂，到目前为止只从藜科植物、菠菜、甜菜和藜属植物中分离到。然而，在我们最近对菊科植物游动孢子引诱剂的调查中，鸡冠花发现其中一种活性很高的游动孢子引诱剂确实是亲游动孢菌素A。

1.The zoospores of phytopathogenic Oomycete, Aphanomyces cochlioides show clear positive chemotaxis to the host-specific singanl substances. The reputed receptor for the host-specific attractant toward the zoospores of spinach root rot pathogen, A.cochlioides wsa surveyed by using a biotin conjugated azidoflavone as a probe and resulted in 40 and 70 kDa membrane proteins on electropholetic gel plates.2.The events caused by signal transduction regarding the life-cycle development of a Peronosporomycete (Oomycete) Aphanonyres cochlioides has been studied by using microscopic techniques. An interesting difference in F-actin profiles was observe between two kinds of custospores, one developing ahead to hyphal germination and the other rejuvenating to regeneration of zoospores.3.About 150 rhizoplane bacteria were isolated from host and non-host plants, and our dual culture bioassay revealed that more than 5 % of isolates caused severe morphological alterations on phytopathogenic Oomycete Aphanomyces cochlioides and the fungal growth was strongly inhibited. From these results, we proposed that this method is new and effective way to find biological control agents against soilbome phytopathogens.4.Cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone) known as the host-specific zoospore attractant for a spinach root rot pathogen has been isolated so far only from Chenopodiaceae plants, spinach, sugar beet, and Chenopodium album, however, in our recent survey of zoospore attractants in Amamthaceae plant, Celosia cristata revealed that one of the active princilpes was indeed cochliophilin A.