引起大豆根腐病的镰孢菌种类鉴定

Species identification of Fusarium causing root rot on soybean

大豆是重要的粮食和油料作物,在中国经济发展中起着重要作用,病虫害是制约大豆生产的重要因素,由镰孢菌属(Fusarium)引起的根腐病是世界上最具破坏性的病害之一[1]。该病害通过破坏维管束影响水和养分的吸收和运输,从而减少光合作用进而导致植物过早死亡[2]。根腐病是一种世界性的土传病害,主要侵染大豆茎基部至根部,引起根茎腐烂,一般田块减产10%~30%,重病田块减产达60%以上,严重时甚至造成绝产[3]。

Fungal disease is an important factor restricting the high and stable yield of soybean.In order to clarify the taxonomic status of pathogenic isolates SoyITS1 and SoyITS12 isolated from the diseased soybean roots with the symptoms of root rot,the two isolates were identified on the basis of morphological traits and sequence analyses of translation elongation factor 1-α(EF1-α)and RNA polymerase II beta subunit(RPB2).The results showed that the colonies of isolates SoyITS1 and SoyITS12 were milky white when they were cultured on PDA medium.After 7 d of culture on CLA medium,the conidia were falciform with blunt apical cells and slightly crooked base cells,with 3-4 septa,the size of which was(20-40)μm×(3.5-6.8)μm(n=50).BLAST sequence comparison showed that the consistency between strains SoyITS1 and SoyITS12 and Fusarium falciforme was 86.7%-98.8%.In the two monogenic and polygenic phylogenetic trees,SoyITS1 and SoyITS12 strain was clustered in the same evolutionary branch as F.falciforme.Strain SoyITS1 and SoyITS12 were identified as F.falciforme based on morphological characteristics,homology analysis and phylogenetic tree analysis.