Diversity of Sooty Blotch and Flyspeck Fungi on Cider Apples in Spain

Abstract

Fungi in the sooty blotch and flyspeck (SBFS) complex blemish fruit and reduce the market value of fresh-market apples. In 2010, apples were collected from 16 orchards in northern Spain that had received few to no fungicide sprays. SBFS colonies with the subtending cuticle were excised, pressed, and shipped to Ames, Iowa, United States, for isolation. A total of 213 sequences were aligned after a portion of the rRNA was amplified with primer pair VG9/LR5, and two regions were sequenced with primer pairs ITS1/ITS4 and LROR/LR5. Distance and parsimony analyses of the 28S gene sequences were used to compare the collection with previously isolated SBFS species. Most isolates (89%) were within the subclass Dothideomycetes, order Capnodiales. Within this order, the predominant genus was Schizothyrium (anamorph Zygophiala) (86 isolates), including S. pomi, Z. cryptogama, Z. cylindrica, and two previously undescribed putative species. Also widely prevalent were Microcyclosporella mali (45 isolates), four Microcyclospora spp. (36 isolates), and four Stomiopeltis-like putative species (34 isolates). Seven isolates were within the Eurotiomycetes. Twenty-five putative species were delineated using the ITS sequences and morphological characterization. These included 11 species previously named and reported as members of the SBFS complex, two putative SBFS species that were previously reported but have not yet been described, and 12 newly detected putative SBFS species. The findings add substantially to knowledge of the taxonomic diversity of this ectophytic fungal assemblage in Europe. [Figure: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Keywords

• Chaetothyriales
• Dissoconiaceae
• Europe
• LSU
• Mycosphaerellaceae
• PCR