Identification and biological characteristics of the pathogens of Chinese fir anthracnose in Guangxi

【Objective】To identify and determine the biological characteristics of the pathogens causing Chinese fir anthracnose in Guangxi to provides a basis for their control.【Method】Typical anthracnose samples were collected from Chinese fir seed orchards and woodlands in Hechi,Baise,Guilin,Liuzhou,Hezhou,and Nanning,in Guangxi,and thefungiwere isolated by tissue separation and purification. Their pathogenicity was tested according to Koch's method and their identity determined through morphological studies and multi-gene phylogenetic analysis of their internal transcribed spacer(ITS),chitin synthelase 1(CHS1),glyceraldehyde 3-phosphoric acid dehydrogenase(GPDH),tubnlin2(TUB2),actin(ACT)sequences.The biological characteristics of Colletotrichum fructicola and C. camelliae were determined by the plate culture method.【Result】A total of 60 strains of anthracnose fungi were isolated from collection sites and the all of the isolates could infect healthy Chinese fir leaves,but with different pathogenicities. The pathogens were identified as C. fructicola and C. camelliae from their phenotypic characteristics and multilocus sequence analysis. The study of their biological characteristics indicated that the optimum temperature for mycelial growth and sporulation of C. fructicola and C. camelliae was 28 and 25 ℃,respectively. Light had no obvious effect on the mycelial growth of C. fructicola,but was beneficial to the mycelial growth of C. camelliae. Complete darkness was beneficial to the spore production of the two pathogens. The optimum p H value for mycelial growth of the two pathogens was 4,and the optimum pH value for spore production was 4 and 5 for C. fructicola and C. camelliae,respectively. The better carbon sources for C. fructicola and C. camelliae was D-maltose for mycelium growth,whereas the optimal carbon source for spore germination was lactose and D-sorbitol for C. fructicola,and soluble starch and arabinose in C. camelliae. The best nitrogen sources for C. fructicola and C. camelliae were peptone and yeast powder during mycelium growth,and the optimal nitrogen for spore germination was yeast powder in C. fructicola,and yeast powder and beef extract in C. camelliae.【Conclusion】The pathogens of Chinese fir anthracnose in Guangxi are identified as C. fructicola and C. camelliae. Temperature,pH,carbon and nitrogen sources have significant effects on mycelial growth and sporulation of C. fructicola and C. camelliae,while the effects of light on the two pathogens are slightly different.