Polyphasic taxonomy of four passalora-like taxa occurring on fruit and forest trees

Mounes Bakhshi,Uwe Braun,Hossein Taheri,Rasoul Zare

doi:10.1007/s11557-021-01725-5

Abstract

Species of Passalora s. lat. are phytopathogenic fungi that generally cause leaf spot diseases on a broad variety of plants throughout the world. During our investigations exploring cercosporoid fungi associated with leaf spot symptoms of fruit and forest trees in northern and north-western Iran, several passalora-like fungi were isolated from symptomatic leaves of trees belonging to the Fabaceae, Malvaceae, Rosaceae, and Ulmaceae. A polyphasic taxonomic approach applying molecular data, morphological features, and host data was employed to identify the isolates. In a multi-gene phylogenetic analysis (LSU, ITS, and RPB2), these isolates are clustered in four clades in the Mycosphaerellaceae. The taxa encompassed Paracercosporidium microsorum on Tilia platyphyllos, Prathigadoides gleditsiae-caspicae gen. et. sp. nov. on Gleditsia caspica, Pruniphilomyces circumscissus on Prunus avium and Prunus cerasus, and Sirosporium celtidis on Celtis australis. The new genus Prathigadoides and its type species Prathigadoides gleditsiae-caspicae are molecularly distinct from all phylogenetically related genera, and some characteristics of the conidiophores and conidia differ from those of the morphologically similar species Prathigada condensata on the North America Gleditsia triacanthos.

Highlights

The Mycosphaerellaceae is a large and diverse family in the order Mycosphaerellales, class Dothideomycetes (Crous et al 2009; Abdollahzadeh et al 2021)
During our investigations exploring cercosporoid fungi associated with leaf spot symptoms of fruit and forest trees in northern and north-western Iran, several passalora-like infections were isolated from symptomatic leaves of different trees belonging to the Fabaceae, Malvaceae, Rosaceae and Ulmaceae
The revealed taxa encompass Paracercosporidium microsorum on Tilia platyphyllos, Prathigadoides gleditsiae-caspicae gen. et. sp. nov. on Gleditsia caspica, Pruniphilomyces circumscissus on Prunus avium and Prunus cerasus, and Sirosporium celtidis on Celtis australis

Summary

Introduction

The Mycosphaerellaceae is a large and diverse family in the order Mycosphaerellales, class Dothideomycetes (Crous et al 2009; Abdollahzadeh et al 2021). (Minnis et al 2011; Braun et al 2013), Pallidocercospora Crous, Paracercospora Deighton (Crous et al 2013), Phaeocercospora Crous (Crous et al 2012) are genera belonging to the Pseudocercospora complex They are morphologically generally similar to or only somewhat different from Pseudocercospora, but they were clearly segregated on the basis of phylogenetic data as distinct genera (Crous et al 2013; Hyde et al 2013). The phylogenetic structure of Passalora is, more complicated than the other cercosporoids

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