Pathogen Diversity Of Apple Sooty Blotch And Flyspeck

Sooty blotch and flyspeck become the main disease of apple in these years, as a late-season disease of pomaceous fruit, resulting in produce that is gegerally unacceptable to consumers and bringing loss of value. Fungi of the sooty blotch and flyspeck complex colonize the cuticle of apple fruit, the appearance of the fruit is cosmetically damaged with dark smudges and groups of tiny spots. The appearance of mycelial types of sooty blotch and flyspeck on apple fruit is variable, such as ramose, punctuate, fuliginous and rimate etc.Through morphological identification and ITS sequence analysis of ribosomal DNA of isolates from main producing region of apple in China, the diversity of sooty blotch and flyspeck fungi of apple was approved. ITS PCR-RFLP (restriction fragment length polymorphisms) with restrict endonuclease of BsuRâ… and Mspâ… was applied to provide experiences for fast detection and identification of these fungi.The result of PCR-RFLP was consistent with morphological identification, and ITS sequences analysis results, and this indicated that using these two restrict endonuclease to identify these fungi was feasible. In this research, three new species were described, namely Dissoconium mali, Dissoconium multiseptatae, Strelitziana mali. The restriction patterns of ITS digested with Msp-1 and BsuR-1 respectively were established. A most parsimony tree was constructed with PAUP 4.0b10 used 61 ITS sequences of sooty blotch and flyspeck fungi and 51 ITS sequences downloaded from GenBank. The results of research indicated that the fungi of sooty blotch and flyspeck distribute in two classes of Ascomycetes, Dothidiomycetes and Chaetothyriomycetes, 3 orders and 11 genuses and some are difficultly identified even just to genus by both morphology and sequences.