Identification And Phylogeny Of The Pathogens Causing Stem Canker Of Carya Cathayensis

Species of the Botryosphaeriaceae are important pathogens causing cankers and die-back onmany woody plants. Botryosphaeria dothidea was identified as canker-associated fungalpathogen on the Chinese Hickory (Carya cathayensis) in the previous studies. The relationshipbetween other species of Botryosphaeriaceae and hickory canker remains unclear. This studyisolated and identified a various species of Botryosphaeriaceae associated with canker onChinese Hickory, based on comparisons of anamorphic morphologyes and sequence data ofinternal transcribed spacer (ITS) region from rDNA, The main results are as follows:1. These analyses distinguished three clades amongst isolates associated with the diseases.Morphological observations and ITS sequence blast provided consistent evidences forrecognizing three speices as F. aesculi, F. fabicercianum, D. seriata.2. The species F. aesculi was thought to be the most frequent species (with isolation rate of71.42%) within the collection of isolates, followed by F. fabicercianum and D. seriata with aminor fraction of the isolates (with isolation rate of14.28%, respectively).3. In pathogenicity test, all species caused canker on Chinese Hickory with differentvirulence and different index of decease infection. F. aesculi strains, with strongestpathogenicity, its disease index was77.77, followed by F. fabicercianum strains of disease indexwas15.56, D. seriata strains pathogenic, the disease index was6.67,4. According the characters of morphology and molecular biology, to choose7pathogens(marked1CH,23CH,16NG,31CP,19GT,7NG,13NG) as respective strains, and upload theseven DNA ITS sequences to GenBank database, while accessing the accession numberrespectively from KC527822to KC527828,5. The analyse of molecular phylogeny are consist with the results of Morphologicalobservations,6. This is the first report of D. seriata and F. fabicercianum associated with stem canker ofChinese Hickory.7. Some isolation strains weren’t the Botryosphaeriaceae strains. Morphologicalobservations and ITS sequence blast provided consistent evidences for recognizing these strainsas Pestalotiopsis microspora. In pathogenicity test, this species didn’t cause canker on Chinese Hickory.