Modes of action and structure of host-selective pathogenicity factors produced by Phytophthora pathogens

在这个项目中，从致病疫霉（Phytophthora spp.）中分离纯化了一种具有寄主选择性抑制活性的葡聚糖，并对其作用方式进行了分析。结果表明：1）从接种致病疫霉游动孢子的透析管内液和孢子在含Ca ~（2+）蒸馏水中的萌发液中分离到一种磷酸葡聚糖（P-SG）; 2）从致病疫霉游动孢子的透析管内液中分离到一种磷酸葡聚糖（P-SG）; 3）从致病疫霉游动孢子的透析管内液中分离到一种磷酸葡聚糖（P-SG）; 4）从致病疫霉游动孢子的透析管内液中分离到一种磷酸葡聚糖（P-SG）; 5）从致病疫霉游动孢子的透析管内液中分离到一种磷酸葡聚糖（P-SG）; 6）从致病疫霉游动孢子的透析管内液中分离到一种磷酸葡聚糖（P-SG）。SG的特征在于葡聚糖在18-23聚合葡萄糖，每个分子具有1-4个磷酸盐，以及β-1，3-半乳聚糖酶和磷酸酶敏感的葡聚糖。P-SG在不同pH下通过凝胶过滤柱的高效液相色谱分析得到的P-SG仍由多个葡聚糖分子组成，其结构有待进一步分析; 3）通过检测受试组织的自显影，设计了一种抑制剂活性的检测系统; 4）发现P-SG抑制Ca^<2+> 5）P-SG与寄主质膜表面存在分子相互作用，但这种作用受到质膜悬浮液中葡聚糖酶和磷酸酶的干扰，为进一步研究该抑制剂的作用机制，需要进一步完善体外培养体系。

In this project, isolation and purification of the active host-selective suppressor-glucans from Phytophthora spp.and analyzes of the their mode of action were carried out and the following results were obtained.1) A phospho-glucan (P-SG) was isolated from inner solution of a dialysis tube on which zoospore-suspension of P.infestrans was inoculated as well as spore-germinated fluid in Ca2+ containing destilled water.2) The P-SG was characterized by glucans with polymerization of glucose at 18-23 and with 1-4 phosphate per molecule and beta-1,3-galucanase- and phosphatase sensitive glucans. The P-SG was still consisted of several glucan molecules since it was further separated through HPLC analyzes on gel filtration columns at different pH.The detailed analyzes of their structures were remained to be carried out.3) A assay system for suppressor activity was devised by testing the reduction of elicitorstimulated chemiluminescence on an autophotography of the test tissued.4) P-SG was found to inhibit the Ca^<2+> movement from plasmamembrane which was stimulated by elicitor treatment and resultantly inhibit the activation of the superoxide generating system.5) A molecular interaction between P-SG and surface of host plasmamembrane was tested, but the results was disturbed by the presence of glucanase and phosphatase in the plasmamembrane suspension, The further improvement of the in vitro systemn was requested for analyzes of the molecular mechanisms of the supperessor.