Penicillium expansum (Link) Thom. is one of the most important postharvest pathogens of apple fruit worldwide. It causes blue mold, a decay that can lead to significant economic losses during storage, which can also impact fruit destined for processing due to the production of carcinogenic mycotoxin patulin. Apple fruit cvs. Idared, Golden Delicious and Braeburn with blue mold symptoms were collected from five storage facilities in Serbia and nine fungal isolates were obtained. Pathogenicity of the isolates was tested and proven by artificial inoculation of healthy apples cv. Idared. In order to identify the causal agents of decay, morphological and molecular methods were used. Colony morphology and microscopic features were observed on differential media, and isolates were tested for the production of cyclopiazonic acid. Molecular analysis included PCR amplification with species specific primers for P. expansum based on polygalacturonase gene (Pepg1), universal primers for internal transcribed spacer rDNA region and primers based on ?-tubulin gene. All isolates formed compact blue green colonies with characteristic earthy odor. Conidiophores were terverticillate with smooth septate stipes and conidia were smooth, globose to subglobose, born in colums. The average size of conidia was 3.38 ? 0.49 (SD) x 3 ? 0.36 (SD) ?m. Using species specific primers PEF/PER the texpected amplicons of ~404 bp were obtained in all nine tested isolates and PCR conducted with the Bt-LEVUp4/ Bt-LEV-Lo1 and universal ITS1/ITS4 primer pairs generated amplicons of the expected sizes of ~800 bp and ~600 bp, respectively. MegaBlast analyses of the 2X consensus of nucleotide sequences of the isolate JP1 partial ?-tubulin gene and ITS region showed 99-100% and 100% similarity with several P. expansum sequences of corresponding regions of this species deposited in GenBank. Based on morphological and molecular features, the isolates obtained from decayed apple fruit collected in several storage facilities in Serbia were identified as P. expansum.

Brown rot, caused by Monilinia spp., is an economically important pre and postharvest disease of pome and stone fruits worldwide. In Serbia, apple is the most widely grown pome fruit, and the distribution of economically important Monilinia spp. responsible for apple brown rot is unknown. Hence, we conducted a three year survey, from 2010 to 2012, where 349 isolates were obtained from six orchards and four storage facilities from five different apple cultivars with brown rot symptoms. Morphological characterization of the isolates, multiplex PCR, and phylogenetic analysis revealed four species: M. fructigena, M. laxa, M. fructicola, and Monilia polystroma. All species were found in the orchard and in storage, with M. fructigena predominating, followed by M. polystroma. Representative isolates were analyzed in vitro and in vivo where differences in growth rate, sporulation, and virulence on apple fruit were observed. Findings from this investigation demonstrate diversity in the species responsible for pre ...

In Europe, two fastidious phloem-limited pathogens, ’Candidatus Phytoplasma solani’ (16SrXII-A) and ’Candidatus Arsenophonus phytopathogenicus’, are associated with rubbery taproot disease (RTD) and syndrome basses richesses (SBR) of sugar beet, respectively. Both diseases can significantly reduce yield, especially when accompanied by root rot fungi. This study investigates the presence, geographic distribution and genetic traits of fastidious pathogens and the accompanying fungus, Macrophomina phaseolina, found on sugar beet across four geographically separated plains spanning seven countries in Central Europe. The survey revealed variable incidences of symptoms linked to these fastidious pathogens in the Pannonian and Wallachian Plains, sporadic occurrence in the North European Plain, and no symptomatic sugar beet in the Bohemian Plain. Molecular analyses unveiled the occurrence of both ’Ca. P. solani’ and ’Ca. A. phytopathogenicus’ throughout Central Europe, with a predominance of the phytoplasma. These fastidious pathogens were detected in all six countries surveyed within the Pannonian and Wallachian Plains, with only a limited presence of various phytoplasmas was found in the North European Plain, while no fastidious pathogens were detected in Bohemia, aligning with observed symptoms. While 16S rDNA sequences of ’Ca. P. solani’ remained highly conserved, multi-locus characterization of two more variable loci (tuf and stamp) unveiled distinct variability patterns across the plains. Notably, the surprising lack of variability of tuf and stamp loci within Central Europe, particularly the Pannonian Plain, contrasted their high variability in Eastern and Western Europe, corresponding to epidemic and sporadic occurrence, respectively. The current study provides valuable insights into the genetic dynamics of ’Ca. P. solani’ in Central Europe, and novel findings of the presence of ’Ca. A. phytopathogenicus’ in five countries (Slovakia, Czech Republic, Austria, Serbia, and Romania) and M. phaseolina in sugar beet in Slovakia. These findings emphasize the need for further investigation of vector–pathogen(s)–plant host interactions and ecological drivers of disease outbreaks.