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[Objective] To identify the pathogen of anthracnose of Camellia osmantha Ye CX,Ma JL et Ye H in Guangxi, determine its biological characteristics, and provide disease reference basis for the selection and breeding of disease-resistant C. osmantha.[Method] Samples of typical anthracnose from C. osmantha forests in Nanning city, Laibin city and Chongzuo city were collected, and the pathogenic strains were obtained by tissue separation method and Koch’s rule. According to the description of the morphological characteristics of the pathogen and the multi gene molecular phylogenetic analysis of ribosomal transcription spacer (ITS), actin (ACT), chitin synthase (CHS1） and glyceraldehyde 3-phosphate dehydrogenase (GPDH), the pathogenic strains were identified, and the biological characteristics of the pathogen were determined by plate method.[Result] A total of 76 strains of Colletotrichum fungi were isolated from typical anthrax samples collected from C. osmantha woodlands in Nanning, Laibing and Chongzuo, Guangxi. The strains were pathogenic to healthy C. osmantha leaves, but the pathogenicity was slightly different. The average diameters of the inoculated spots of representative strains CXNN02,CXLB08 and CXCZ09 in vitro were 6.48,6.39 and 5.20 mm, respectively. The inoculated spots in vivo were slightly smaller than the former, which were 5.53,5.33 and 4.97 mm, respectively. The pathogenicity of CXNN02 strain was slightly stronger. The representative strain CXNN02 had a round colony on the PDA medium, and the hyphae were gray to dark gray, the aerial hyphae are lush, fluffy, and black pigment was produced on the back. The hyphae grow faster, with an average growth rate of 11.75 mm/d. The conidia were smooth, colorless, unicellular, cylindrical, with a blunt or slightly pointed tip, and the size was (13.30-20.67）μm× (3.39-7.48）μm. Appressorium of conidia was light brown to brown, single or multiple, round or nearly round, with complete edges, and the size was (6.50-10.69）μm× (5.17-9.50）μm. Through the analysis of the phylogenetic tree analysis of the morphology and multi-site gene phylogeny of the representative strains CXNN02, CXLB08, CXCZ09, it was determined that Colletotrichum fructicola was the pathogen of C. osmantha anthracnose in Guangxi. The results of biological characteristics measurement showed that, the optimum temperature for mycelial growth and spore production of C. fructicola was 28 ℃,the optimum pH for mycelial growth was 4-5,the optimum pH for spore production was 6,the best carbon source for mycelial growth was D-maltose, D-glucose, D-fructose and D-xylose, the best carbon source for spore production was lactose, and the better nitrogen sources were beef extract, peptone and yeast powder. The spore yield of yeast powder as nitrogen source was the largest; Complete darkness was conducive to the mycelial growth and spore production of C. osmantha anthracnose.[Conclusion] The pathogen of anthracnose of C. osmantha in Guangxi belongs to C. fructicola. The mycelial growth and spore production of anthracnose of C. osmantha is obviously affected by temperature, pH, carbon and nitrogen sources and light conditions. C. osmantha is a new host of C. fructicola. The biological characteristics of the anthracnose pathogen must be fully understood when selecting disease-resistant varieties of C. oleifera and formulating control measures for anthracnose pathogens. [ABSTRACT FROM AUTHOR]

【Objective】Biological characteristics of Colletotrichum hymenocallidis were tested to provide theoretical basis for control of Dalbergia odorifera T.Chen anthracnose.【Method】Effects of temperatures gradient of 5-40 °C on the mycelium growth,sporulation and spore germination of C.hymenocallidis were studied on PDA medium.Effects of 50 %-100 % different humidity on the conidial germination ofC.hymenocallidis were studied by means of small container air humidity adjustment method.Effects of PDB culture solution with pH 2-12 on the mycelium growth of C.hymenocallidis was determined by liquid culture method.With Czapek media as the base,sucrose and sodium nitrate were replaced by nine kinds of carbon sources or nitrogen sources of the same mass,in order to studied the effects of different carbon sources and nitrogen sources on the mycelium growth,sporulation quantity of C.hymenocallidis.Effects of darkness,continuous illumination and 12 h light and dark alternation on the myceliuml growth,sporulation quantity were studied on PDA medium.【Result】The tested strain grew differently under different temperatures.Extremely high and low temperature were not beneficial to mycelium growth,sporulation and spore germination of C.hymenocallidis.All biological indicators could reach the highest level under 28 °C.The colony diameter,sporulation quantity and spore germination rate were 69.88 mm,3.33×10~6/mL and 94.00 %,respectively.The germination rate of the bacteria was the highest in the water droplets,the germination rate was 93.00 %.The strain could grow in the range of pH 3-12,and the optimum was 5.The different carbon and nitrogen source could be used,the better carbon sources was D-fructose,sucrose,D-xylose,mannitol,D-sorbitol and amylogen,but no significant difference on sporulation(P>0.05).The better nitrogen sources was yeast powder on the mycelium growth and the optimal nitrogen for spore germination was beef extract.The light can accelerate mycelium growth and promote sporulation.【Conclusion】The mycelial growth and sporulation of C.hymenocallidis were significantly affected by temperature,pH,carbon and nitrogen sources and light.The suitable high temperature and high humidity were conducive to the germination of conidia of C.hymenocallidis.The biological characteristics of C.hymenocallidis can be used for effective prevention and control in production. [ABSTRACT FROM AUTHOR]