宁夏地区不同品系番茄主要病毒病种类鉴定及复合侵染研究.

【Objective】The study aimed to clarify the classification and biological characteristics of the pathogen causing anthracnose of Loropetalum chinense var. rubrum in Guangxi, so as to provide a theoretical basis for the diagnosis and scientific control of the disease.【Method】The pathogen was isolated by tissue separation method and its pathogenicity was verified by living leaf inoculation tests. Furthermore, the pathogen was identified by its morphological characteristics and phylogenetic analysis of multi-locus[internal transcribed spacer (ITS), actin (ACT), (β-tubulin) TUB2, glyceraldehyde-3-phosphate dehydrogenase (GAPDH),chitin synthase (CHS-1) and calmodulin (CAL)] sequences. The effects of different temperature, pH, carbon source, nitrogen source and fungicide on the mycelial growth of pathogen were measured by colony growth rate method.【Result】Six fungal strains with consistent morphology and pathogenicity were isolated from diseased leaf tissue. The colony was nearly round, gray to dark gray in the middle, and gray white at the edge. The aerial mycelium was loose and flocculent. And the conidia were single celled and long oval. The morphological characteristics were consistent with those of Colletotrichum fructicola. The ITS, ACT, TUB2, GAPDH, CHS-1 and CAL gene sequences of representative strain H6 were amplified by PCR and analyzed by BLAST in NCBI. The results showed that these sequences had 99%-100% homology with several C. fruticola strains. Furthermore, these genes were used to construct phylogenetic trees. Strain H6 was found in the same branch as C. fructicola. Therefore, the pathogen was identified as C. fruticola. The results of biological characteristic tests showed that the optimum temperature, pH, carbon and nitrogen sources for mycelial growth of strain H6 were 28.0 °C,8.0,werexylitol and L-proline, respectively. Pyraclostrobin, picoxystrobin, ethylicin, carbendazim and prochloraz had strong inhibitory effect on mycelial growth of strain H6.【Conclusion】The pathogen causing anthracnose of L. chinense var. rubrum in Guangxi was identified as C. fructicola by morphological and molecular biological methods. The conditions of temperature, pH, carbon source and nitrogen source that were most suitable for the growth of the pathogen were verified. At the same time, several fungicides with strong inhibitory effect on the pathogen were also determined. [ABSTRACT FROM AUTHOR]