Didymella corylicola sp. nov., a new fungus associated with hazelnut fruit development in Italy

Marzia Scarpari,Alessandra Belisario,Giuseppe Di Giambattista,Salvatore Vitale,Hermann Voglmayr,Tommaso De Gregorio,Laura Luongo,Mariangela Petrucci,Giulio Schreiber

doi:10.1007/s11557-020-01562-y

Marzia Scarpari, Alessandra Belisario + Show 7 more

Open Access

https://doi.org/10.1007/s11557-020-01562-y

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Abstract

A new fungal species constantly associated with hazelnut (Corylus avellana) fructification starting from its primordia is described. The fungus is associated with hazelnut fruit during all their developmental stages, being consistently more present in spring (March–June). A 4-year survey has been conducted, from young fruit formation to full kernel maturity including also the post-harvest phase, to collect fungi associated with damaged/discoloured kernels. A collection of 60 isolates of a new species has been obtained in this study, which is here described as Didymella corylicola sp. nov. Multi-locus phylogenies based on four genomic loci (nuITS and LSU rDNA, RPB2 and TUB2) in combination with morphological data confirmed the fungus to represent a new species of Didymella (Didymellaceae). The occurrence of D. corylicola sp. nov. might have an impact on the quality of hazelnut production by contributing to kernel defects.

Highlights

Hazelnut (Corylus avellana L.) is native to Europe and Western Asia where it is widely distributed (Olsen 2013; Enescu et al 2016)
Colonies were grown on 2% (w/v) malt extract agar (MEA, VWR), potato dextrose agar (PDA, Sigma-Aldrich), corn meal agar (CMA, Sigma-Aldrich) supplemented with 2% w/v dextrose (CMD), oatmeal agar (OA, Sigma-Aldrich) and hazelnut extract agar (HEA; 25 g/l fresh chopped hazel twigs, autoclaved in 2% agar)
Re-isolations from the margin of lesions cultured on PDA gave colonies with the same morphological characters as those used for inoculation, confirming Koch’s postulates

Summary

Introduction

Hazelnut (Corylus avellana L.) is native to Europe and Western Asia where it is widely distributed (Olsen 2013; Enescu et al 2016). Hazelnut cultivation is dispersed all over Italy, from north to south, with main production located in Piedmont (26%), Latium (32%), Campania (28%) and Sicily (9%) regions (ISTAT, http://dati.istat.it/). These percentages just give an indication since production may vary from year to year. Hazelnut is characterized by good rusticity which makes it an adaptable fruit tree species compared to other nut species such as almond, walnut and pistachio It is affected by several diseases and fungal pathogens which can be harmful in altering the kernel and reducing harvest quality and yield. Sphaceloma coryli), has been reported (Minutolo et al 2016), while in central Italy (Latium, Viterbo province) and in Campania, Alternaria spp., Colletotrichum spp., Fusarium spp. and Diaporthe spp. have

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