Oomycetes mode of action

This primary mode of action of tomatine, that involves the formation of complexes with membrane sterols is similar to that described for polyene antibiotics [2, 4], and results in pore formation and loss of membrane integrity. This mode of action is supported by the reduced activity of tomatine on sterol-free bacteria and Oomycete fungi such as Pythium and Phytophthora [15, 28], and the strongly reduced toxicity of hydrolysis products of the glycoalkaloid which fail to bind sterols [57]. 

Here we review our research results concerning zoospore attractants, repellents, cytotoxins and inhibitors of zoospore motility together with bioassay systems to survey chemical regulators toward zoospores. The first part of this review described some new findings on the effects of host-specific plant signals on chemotaxis and differentiation of oomycete zoospores. The potential role and mode of action of nonhost secondary... 

Despite many studies, the biochemical mode of action of several fungicides and bactericides remains unclear (Table 12.16). Notably, two compounds, cymoxand (trade name Curzate ) and fosetyl-Al (trade name Alliette ) have gained broad, long-term market acceptance for Oomycete control. The compounds of this table... 

Dimefluazole did not achieve commercial status, but this compound and an analog were the subject of a detailed investigation of the mode of action [103]. The conclusion was that the azole moiety acts as a leaving group, so that the sulfonyl group of the a.i. binds covalently to a nucleophile of the Qi-center of oomycetes [103]. The different submolecular target sites of cyazofamid and Qo-site inhibitors lead to lack of cross resistance. 

Since zoxamide has a different mode of action from other products used in the Oomycete market, there is no likelihood of cross-resistance to existing products such as metalaxyl, dimethomorph, cymoxanil or strobilurins. Consequently, zoxamide provides a unique tool for resistance management in the Oomycete fungicide market. 

Fluopicolide, a new Anti-oomycetes Fungicide with a New Mode of Action inducing Perturbation of a Spectrin-like Protein... 

Fluopicolide-induced delocalization of spectrin-like proteins represents a new mode of action that is different to that of known anti-oomycete fungicides on the market. Spectrin-like proteins are poorly characterized in fungi and oomy-... 

Dichloro-4-(2-chloro-l,l-dimcthylcthyl)pyridazinc 1 appears to be part of a very small group of compounds which both control Oomycetes organisms and demonstrate mobility within some plant tissues. It is hoped that this group of compounds can serve as a basis for discovering other compounds with the same mode-of-action and similar unique properties. 

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