Study On Molecular Phylogeny Of Colletotrichum On Common Landscape Plants In Chengdu

Anthracnose is one of the most common and serious diseases on landscape plants.To clarify the Colletotrichum species of common landscape plants in Chengdu and to provide a theoretical reference for diagnosis,treatment and further research of disease.In this study,more than 150 diseased leaves of suspected anthracnose were collected from 11 areas including Wenjiang District and Pengzhou in Chengdu.The total of 122 Colletotrichum strains were obtained through tissue separation,microscopic observation and single-spore purification,all of isolates mainly were covered 106 species of common landscape plants belonging to 87 genera of 54 families.According to morphology characteristics and the glyceraldehyde-3-phosphate dehydrogenase(GAPDH)gene sequences,39 representative strains were chosen from 122 strains for phylogenetic analysis of multi-locus sequences,including the nuclear ribosomal internal transcribed spacer(ITS)region,actin(ACT),chitin synthase(CHS-1),the ?-tubulin(TUB2),calmodulin(CAL),histone(HIS3)and GAPDH genes,and phylogenetic analysis based on Apn2/Mat1-2-1(ApMat)gene for isolates within the C.gloeosporioides species complex.The method of comprehensive morphology and molecular phylogeny identified the 122 strains of this study as 19 species,among which 109 strains including 3 new species were first discovered on their respective host plants.The number of C.siamense in all strains was the highest,it comprising 48 isolates,accounting for 39.3% of the total number of strains.The pathogenicity test showed that except for C.sp2,the other 18 species inoculated to apple could be pathogenic and had no host specialization.In addition,according to the difference of the thickness of the host plant leaves,screening for pathogenicity test methods used different inoculation ways(Rubbing with sandpaper,needling,and no injury).The results showed that rubbing with sandpaperis the best method for the host plants with thick leaves.For host plants with relatively thin leaves,needling is the best treatment.