Septoria-like pathogens causing leaf and fruit spot of pistachio

Abstract

Several species of Septoria are associated with leaf and fruit spot of pistachio (Pistacia vera), though their identity has always been confused, making identification problematic. The present study elucidates the taxonomy of the Septoria spp. associated with pistachio, and distinguishes four species associated with this host genus. Partial nucleotide sequence data for five gene loci, ITS, LSU, EF-1α, RPB2 and Btub were generated for a subset of isolates. Cylindroseptoria pistaciae, which is associated with leaf spots of Pistacia lentiscus in Spain, is characterised by pycnidial conidiomata that give rise to cylindrical, aseptate conidia. Two species of Septoria s. str. are also recognised on pistachio, S. pistaciarum, and S. pistaciae. The latter is part of the S. protearum species complex, and appears to be a wide host range pathogen occurring on hosts in several different plant families. Septoria pistacina, a major pathogen of pistachio in Turkey, is shown to belong to Pseudocercospora, and not Septoria as earlier suspected. Other than for its pycnidial conidiomata, it is a typical species of Pseudocercospora based on its smooth, pigmented conidiogenous cells and septate conidia. This phenomenon has also been observed in Pallidocercospora, and seriously questions the value of conidiomatal structure at generic level, which has traditionally been used to separate hyphomycetous from coelomycetous ascomycetes. Other than DNA barcodes to facilitate the molecular identification of these taxa occurring on pistachio, a key is also provided to distinguish species based on morphology.

Fungal Planet description sheets: 154–213

“…Notes — In resolving the Septoria/Pseudocercospora complex occurring on pistachio, Crous et al (2013c) reported that contrary to the recent circumscription of Pseudocercospora s.str. ( Crous et al 2013a ), a species with pycnidial conidiomata and pigmented conidia, Septoria pistacina (= P. pistacina ), also proved to be a member of Pseudocercospora .…”

Relationship between soil composition, diversity and antifungal properties ofBacillusspp. isolated from southeastern Anatolia

“…Hence, Alternaria spp., Aspergillus flavus, Pseudocercospora pistacina, and Septoria sp. are the main disease-causing fungal agents in the pistachio orchards of Turkey [4,5]. P. pistacina and Septoria sp.…”

Liberomyces pistaciae sp. nov., the causal agent of pistachio cankers and decline in Italy

“…Although pistachio is characterised by good rusticity, it is subject to several fungal diseases known to afflict pistachio trees in the Mediterranean area. Of these, the most commonly reported are phylloptosis, leaf spots mainly caused by Septoria pistaciae , S. pistaciarum and Pseudocercospora pistacina , gum cankers by Cytospora terebenthi and branch and twig cankers by Botryosphaeria dothidea ( Chitzanidis 1995 , Teviotdale et al 2002 , Vitale et al 2007 , Crous et al 2013 ). The latter is widespread and already present as a latent pathogen in numerous plant communities in various parts of the world ( Marsberg et al 2017 ).…”