Identification and Biological Characteristics of a Colletotrichum fructicola Causing Chestnut Internal Rot Disease
Chestnut internal rot is the main disease of chestnut during postharvest storage,which causes rot and mildew of chestnut kernel and brings huge economic losses to production.In order to clarify the pathogenic bacteria and its biological characteristics,the strain ZHZF21 was obtained by tissue isolation method.The strain was identified by morphological characteristics and ITS,TUB2 and CAL multi-gene sequence analysis.The pathogenicity of strain ZHZF21 was determined by mycelial inoculation method,and its biological characteristics were studied.The results showed that the colony of strain ZHZF21 was dark green ring concentric circles,with sexual and asexual reproduction stages.This strain was clustered with Colletotrichum fructicola numbered NDSTY31 in GenBank based on multi-gene sequences.Combined with colony morphological characteristics and molecular tree,strain ZHZF21 was preliminarily identified as Colletotrichum fructicola.The brown lesions after inoculation of strain ZHZF21 were consistent with the natural symptoms.The strain ZHZF21 could grow at 5~35 ℃,the optimum temperature was 25 ℃,the lethal temperature was 45~50 ℃,and the optimum pH was 6.Under the condition of full darkness,strain ZHZF21 grew fastest,the utilization rates of arabinose and yeast were the highest,the utilization rate of lactose was the lowest,and urea could hardly be used.