Morphological and molecular chracterization of Colletotrichum acutatum from feijoa in Italy. First report of Colletotrichum acutatum on Feijoa plants

Feijoa [Acca sellowiana (O. Berg) Burret] is an evergreen shrub or short tree producing edible, sweet and very aromatic fruits. In summer-autumn 2015/16, a severe typical symptoms of anthracnose with an incidence of 10 to 20% were observed on feijoa mature fruits and leaves belonging to gardens and commercial orchards (about 35 hectares) located in Bari and Matera Provinces (southern Italy). In order to isolate the likely pathogen, small pieces of symptomatic plant tissues were plated in Petri dishes containing potato dextrose agar (PDA). A Colletotrichum species was consistently isolated on PDA. Total DNA from 10 isolates was extracted and 4 genes [rDNA (ITS), actin (ACT), β-tubulin (TUB-2) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH)] were amplified with the following primers: ITS5/ITS4; ACT512F+ACT783R; BT1A+BT1B and GDF1+GDR1. Subsequently, all PCR products were checked by agarose gel electrophoresis and directly sequenced. Sequence similarity was checked with the Basic Local Alignment Search Tool (BLAST) program of the NCBI GenBank. Multi-locus phylogenetic analyses based on combined sequences of all 4 genes were performed with the help of MEGA v.6 and SEAVIEW programs.