Characterization of Citrus-Associated < i > Alternaria < /i > Species in Mediterranean Areas

by Francesca Garganese, Leonardo Schena, Ilenia Siciliano, Maria Isabella Prigigallo, Davide Spadaro, Anna De Grassi, Antonio Ippolito, Simona Marianna SanzaniAlternaria brown spot is one of the most important diseases of tangerines and their hybrids worldwide. Recently, outbreaks in Mediterranean areas related to susceptible cultivars, refocused attention on the disease. Twenty representatives were selected from a collection of 180 isolates ofAlternaria spp. from citrus leaves and fruit. They were characterized along with reference strains ofAlternaria spp. Micro- and macroscopic characteristics separated mostAlternaria isolates into six morphotypes referable toA.alternata (5) andA.arborescens (1). Phylogenetic analyses, based on endopolygalacturonase (endopg) and internal transcribed spacer (ITS), confirmed this finding. Moreover, a five-gene phylogeny including two anonymous genomics regions (OPA 1 –3 and OPA 2–1), and the beta-tubulin gene (ß-tub), produced a further clustering ofA.alternata into three clades. This analysis suggested the existence of intra-species molecular variability. Investigated isolates showed different levels of virulence on leaves and fruit. In particular, the pathogenicity on fruit seemed to be correlated with the tissue of isolation and the clade. The toxigenic behavior ofAlternaria isolates was also investigated, with tenuazonic acid (TeA) being the most abundant mycotoxin (0.2 –20 mg/L). Isolates also synthesized the mycotoxins alternari...

Source: PLoS One - September 15, 2016 Category: Biomedical Science Authors: Francesca Garganese Source Type: research