2008-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/653290摘要：青枯病菌(Ralstonia solanacearum)為一土壤傳播性植物病原細菌，其寄主範圍極廣，引發全球許多重要作物的系統性致死萎凋病害。青枯病係一極為複雜之病害，為有效防治此病害我們，深入了解青枯病菌致病機制之運作，自然是十分重要且必需的，但目前人們對其了解仍十分有限。本研究群先前在一項國科會計畫中，已成功篩選出數十株在番茄或阿拉伯芥上致病力降低的青枯病菌Tn5突變株，其中編號23-81的突變株在番茄的病原性不變，但對阿拉伯芥的致病力卻大大降低，顯示這株突變株在某些寄主上的宿主適應力變得十分差，在其基因體中被影響的基因可能參與青枯病菌在不同宿主環境之適應力，值得進行深入研究。在這個兩年的研究計畫中，我們計劃進行以下兩部份研究。第一部分的工作是利用青枯病菌突變株23-81研究參與環境與宿主適應性之操縱子與基因；我們將判定在23-81突變株中Tn5插入點(RSc2190)附近之基因的操縱子(operon)結構，且將構築並分析各種23-81之互補株或特定基因之allelic mutants在各種植物之致病力及各種in vitro特性，藉以確認這些基因在病菌環境及宿主適應力之功能。第二部分的工作是以比較基因體學及功能性研究探討一群在演化上具高度保守性但功能卻完全未知的基因群(DUF82)之功能；我們將利用豐富的資料庫資源，以生物資訊學比較各生物中DUF82基因群之序列、操縱子結構、基因調控之異同，並將在青枯病菌之突變株23-81進行互補試驗及在Xanthomonas spp.與Erwinia spp.進行DUF82之基因缺失試驗，以分析在這些重要的植物病原細菌中，DUF82是否在病原性及各項in vitro特性上有相同功能與特性。藉由這些研究，本計畫不但將獲取有關青枯病菌在不同環境及宿主體內之適應性之調控機制的重要資訊，預計亦可據此研發有效控制此嚴重病害的可能策略，因此，本研究兼具學術及實際應用之重要性。<br> Abstract: Ralstonia solanacearum (Rs), a soil-borne pathogenic bacterium, causes lethal wilt diseases of diverse plants in about 50 families worldwide, including many important crops. To effectively control the diseases caused by Rs, information on the mechanism(s) and genes involved in Rs pathogenesis in plants would surely be highly desirable, and may be necessary. However, our understanding about the extent and sophistication of this pathogen is still very limited. By executing an NSC research project previously, we have identified a group of Rs Tn5 mutants with reduced pathogenicity on Arabidopsis and/or tomato. Among the mutants identified, mutant 23-81 is of special attention because it conferred much reduced pathogenicity on Arabidopsis but behaved normally on tomato. In this two-year project, we propose to further study role(s) of genes tagged in mutant 23-81 in fitness and host adaptation of Rs and other important phytopathogenic bacteria by two approaches. Firstly, we will carry out functional genetic study on the tagged gene RSc2190, which belongs to a group of phylogenetically conserved novel genes of unknown function, namely DUF82, and genes associated with it in Rs mutant 23-81. Complemented strains and gene-targeted mutants will be generated and characterized to determine their in vitro properties and pathogenesis on several plant species. Secondly, by carrying out comparative bioinformatic and functional complementation/mutagenesis studies, we intend to determine whether DUF82 genes play similar role in in vitro properties and pathogenesis of Rs and other important phytopathogenic bacteria. With these proposed studies, we hope not only to gain more insights into mechanism involved in Rs pathogenesis, but also to further find potentially useful and practical strategies for disease control.青枯病菌環境適應性宿主適應性DUF82bacterial wiltRalstonia solanacearumfitnesshost adaptationDUF82