Analysis of the evolutionary history of phytopathogenic fungi of tomato based on gene genealogies

植物病原真菌在何时何地产生致病性？植物病原真菌的致病性是如何进化的？是植物病理学中的重要问题为了给这些问题提供证据，我们主要研究了番茄属植物之间的协同进化。（番茄）和番茄枯萎病菌尖孢镰刀菌（Fusarium oxysporum）的分离培养。在四年的研究中，我们访问了厄瓜多尔，在那里我们可以找到野生L。pimpinellifolium和L. cheesmanii，墨西哥，番茄的驯化发生在2000多年前，我们仍然可以找到原型食用番茄（L。esculentum），L.番茄ceraciforme和creole，以及意大利的那不勒斯，那里的现代食用番茄育种始于世纪。和根际土壤中分离出尖孢镰刀菌。接种试验表明，所有菌株对番茄均无致病性，为非致病性共生菌。基于rDNA-IGS的系统发育分析表明，非致病性F。从野生番茄属（Lycopersicon spp.）与致病菌株（F. oxysporum F. sp. lycopersici）。另一方面，一些非致病性的F。从墨西哥原型番茄和意大利食用番茄中分离的尖孢菌菌株显示出病原菌之间的密切关系。这些结果表明，目前番茄枯萎病病原菌的祖先是墨西哥番茄驯化过程中出现的非致病性共生体。世纪以后，在现代番茄育种和分布过程中，非致病性尖孢镰刀菌对番茄产生了致病性。目前，世界范围内的番茄果实和种子贸易中不仅分布着共生的非致病性尖孢镰刀菌，而且还分布着F。oxysporum F. sp. lycopersici，番茄枯萎病菌。

When and where did plant pathogenic fungi generate pathogenicity?' and 'How has pathogenicity been evolved in plant pathogenic fungi?' are important questions in plant pathology. In order to give evidences to answer these questions, we focused mainly on the coevolution between Lycopersicon spp. (tomatoes) and Fusarium oxysporum, the wilt pathogen of tomato in this study. During the four research years, we visited Ecuador where we could find wild L. pimpinellifolium and L. cheesmanii, Mexico where domestication of tomato occurred more than 2000 years ago and still we can find prototype edible tomato (L. esculentum), L. esculentum vars. ceraciforme and creole, and Naples in Italy where modern breeding of edible tomatostarted in 16th century, collected tissues from symptomless Lycopersicon spp. and rhizosphere soil, and isolated Fusarium oxysporum from the tissues and the soil. All of the isolates showed no pathogenicity on tomatoes by inoculation test and were supposed to be non-pathogenic symbionts. Phylogenetic analysis against the isolates based on rDNA-IGS revealed that non-pathogenic F. oxysporum isolates from wild Lycopersicon spp. carried no phylogenetic relationship with the pathogenic strains (F. oxysporum f. sp. lycopersici). On the other hand, some of the non-pathogenic F. oxysporum isolates from Mexican prototype tomatoes and Italian edible tomatoes showed close relationship between the pathogen. These suggested that the ancient of the present wilt pathogen was the non-pathogenic symbiont which emerged during the domestication of tomato in Mexico. The non-pathogenic E oxysporum have got pathogenicity to tomato during the modern breeding and distribution after 16th century. Now, worldwide trading of tomato fruits and seeds distributes not only the symbiotic non-pathogenic E oxysporum but also F. oxysporum f. sp. lycopersici, the wilt pathogen of tomato.