【作者】 林树文；

【导师】 林文雄； 周淑芬；

【作者基本信息】 福建农林大学 ， 草业（专业学位）， 2016， 硕士

【摘要】 褐斑病、锈病、镰刀枯萎病等真菌病害是我国草坪草的主要病害,严重影响我国草坪业的发展。深入研究病原真菌与草坪草的互作机理是实施病害综合防治措施的重要基础。本研究利用草坪草模式生物二穗短柄草的基因组信息,采用计算方法分析几种草坪草病原真菌与二穗短柄草之间的蛋白互作关系(protein-protein interaction, PPI),以期为病原真菌与草坪草的互作研究奠定基础。主要获得如下结果：基于共进化法(Interolog法)和结构域互作法(DDI法)的计算方法,获得禾草离蠕孢(Bipolaris sorokiniana)-二穗短柄草(Brachypodium distachyon) (BS-BD)、立枯丝核菌(Rhizoctonia solani)-二穗短柄草(RS-BD)、镰刀枯萎菌(Fusarium graminearum)-二穗短柄草(FG-BD)及禾柄锈菌(Puccinia graminis)-二穗短柄草(PG-BD)的跨物种蛋白互作组,分别包括109050、29297、109315和86498个互作对。经数据过滤后,获得高支持度的BS-BD、RS-BD、FG-BD和PG-BD互作组,其中的互作对数分别减少为10396、4435、7892和17934,同时过滤后互作组的数据质量有所提高。高支持度互作组中连接度较高的病菌蛋白主要涉及跨膜转运和蛋白折叠等生物学功能。基于PPI网络节点属性特征,对二穗短柄草物种内蛋白互作网络中病菌靶标蛋白和非病菌靶标蛋白的连接度和介数中心性值进行比较分析,发现病原真菌更倾向于攻击二穗短柄草PPI网络中的关键节点和瓶径节点；而对病菌靶标蛋白的GO和KEGG富集分析则表明,病菌靶标蛋白除了涉及植物防御响应、植物-病原互作等生物过程外,还参与了物质转运、蛋白修饰、糖类物质代谢、信号转导等多种不同生物过程。深入分析预测互作组中的功能相关了网络发现了一些新的病原与寄上蛋白互作关系。在病菌糖基水解酶家族蛋白与寄主蛋白的互作子网络中,除了已验证的病菌木聚糖酶与寄主木聚糖酶抑制子间的互作外,还有一些未见报道的蛋白互作,如病菌内切葡聚糖水解酶(EG)与植物木葡聚糖内转糖苷酶/水解酶(XTH)、病菌蔗糖转化酶与植物ATP酶、病菌糖苷水解酶与植物β-半乳糖苷酶等互作；此外,病菌候选效应子与寄上防御蛋白的互作子网络则提示病菌SOD酶、病菌肽酰-脯氨酰-顺反式异构酶(PPlases)可能与植物防御相关的激酶类分子存在互作。更多还原

【Abstract】 Brown spot caused by Rhizoctonia solani, rust disease by Puccinia spp. and wilt disease by Fusarium spp. were major turfgrass diseases in China, hindering the development of our turfgrass industry. Illustrating the interaction mechanism between these phytopathogenic fungi and turfgrass will promote the implementation of integrated disease management. In our study, the genome information of Brachypodium distachyon, the model species of turfgrass, was used to predict the protein-protein interactions (PPls) between phytopathogenic fungi and turfgrass by computational methods, aiming to provide useful information for further investigation on the host-pathogen interaction mechanism. The results were obtained as follow:Based on Interolog and DDI methods, the interspeices PPI interactomes of Bipolaris sorokiniana-B.distachyon (BS-BD), R.solani-B.distachyon (RS-BD), Fusarium graminearum-B.distachyon (FG-BD) and Puccinia graminis-B.distachyon (PG-BD) were predicted and 109050,29297,109315,86498 interactions were respectively invloved in four interactomes. We refined the interactomes with simple data filtering, and reduced the BS-BD, RS-BD, FG-BD and PG-BD interactomes to 10396,4435,7892 and 17934 PPIs respectively, which improving the quality of predicted interactomes. The proteins with high degree in the refined interactomes were all pathogen proteins, most of them involved in the biological process of transport and protein folding.Based on the node features of PPI network, we compared the node degree and betweenness centrality of all pathogen-targeted proteins with those of non-pathogen-targeted proteins in the intraspeices PPI network of B.distachyon, the results indicated that the pathogen-targeted proteins tend to be the hubs or bottleneck nodes of B.distachyon PPI network. Further, the GO and KEGG enrichment analysis on pathogen-targeted proteins showed that the pathogen-targeted proteins not only involved in the biological process related to plant defense response and plant-pathogen interaction, but also were molecules in the diverse pathways such as material transport, protein modification, carbohydrate metabolic process and signal transduction.Further inspection of functionally relevant subnetworks revealed novel pathogen-host interaction candidates. In the subnet of PPls between pathogen glycosyl hydrolases family and host proteins, expect for the known interactions between pathogen Endo-1,4-beta-xylanase and plant xylanase inhibitor, there were some new PPI candidates such as pathogen endoglucanase (EG) and plant Xyloglucan endotransglucosylase/hydrolase (XTH), pathogen invertase and plant ATPase, pathogen glycoside hydrolase and plant beta-galactosidase. In addition, the analysis on the the subnet of PPIs between pathogen candidate effectors and host defense response proteins indicated that protein interactions existed between pathogen SOD enzymes, peptidyl-prolyl cis-trans isomerase (PPIases) and plant protein kinases involved in defense response.更多还原