György Kövics

Sexual Recombination in the Botrytis cinerea Populations in Hungarian Vineyards

Botrytis cinerea (anamorph of Botryotinia fuckeliana) causes gray mold on a high number of crop plants including grapes. In this study, we investigated the genetic properties of a grape pathogenic population of B. cinerea in the area of Eger, Hungary. A total of 109 isolates from 12 areas were sampled. Based on the sequence of the beta-tubulin (tub1) locus, they all belong to group II, a phylogenetic species within B. cinerea. Seventy-four isolates were classified as transposa, with both the Flipper and Boty transposons, and 10 were classified as vacuma, lacking both transposons. The remaining isolates contained either only Flipper (13) or Boty (12). Multilocus analysis of sequences from tub1 and two other loci (elongation factor 1-alpha, tef1, and a minisatellite from the intron of an ATPase, MSB1) led to poor phylogenetic resolution of strains in individual clades. Analysis of five microsatellites (Bc2, Bc3, Bc5, Bc6, and Bc10) resulted in 55 microsatellite haplotypes within the 109 strains. No correlation was detected among individual haplotypes and the presence/absence of Flipper and/or Boty, the geographic origin, or the year of isolation. Application of the index of association, the chi-square test, and the phi test consistently indicated that the population of Hungarian isolates of B. cinerea undergoes sexual reproduction. However, the index of association test suggested the presence of some clonality, and the fixation index showed a low or occasionally moderate level of fixation in the Flipper populations. We conclude that the B. cinerea populations in Hungary consist of a strongly recombining group II phylogenetic species.

Taxonomical re-evaluation of Phoma-like soybean pathogenic fungi.

Coelomycetous fungi classified in Ascochyta, Phoma, and Phyllosticta have been recorded from spots on leaves and pods of soybeans. Based on the Genealogical Concordance Phylogenetic Species Concept, the authors suggest the re-evaluation of the taxonomic status of Phoma sojicola (syn.=Ascochyta sojicola) and Phyllosticta sojicola. In spite of the former delimitation of Phoma sojicola based on small differences in morphological features, it has proved to be identical to Phoma pinodella. Similarly, it was also confirmed that Phyllosticta sojicola was identical to Phoma exigua var. exigua. The authors supply tools for identification of Phoma-like fungi by combined conventional and molecular methods. Protein-encoding genes (tef1 and beta-tubulin) were successfully applied within the Phoma genus to infer phylogenetic relationships.

Antimicrobial peptides as natural bio-preservative to enhance the shelf-life of food

Antimicrobial peptides (AMPs) are diverse group of natural proteins present in animals, plants, insects and bacteria. These peptides are responsible for defense of host from pathogenic organisms. Chemical, enzymatic and recombinant techniques are used for the synthesis of antimicrobial peptides. These peptides have been found to be an alternative to the chemical preservatives. Currently, nisin is the only antimicrobial peptide, which is widely utilized in the preservation of food. Antimicrobial peptides can be used alone or in combination with other antimicrobial, essential oils and polymeric nanoparticles to enhance the shelf-life of food. This review presents an overview on different types of antimicrobial peptides, purification techniques, mode of action and application in food preservation.

Phoma sojicola comb. nov. and other hyaline-spored coelomycetes pathogenic on soybean

Several hyaline-spored coelomycetes placed in Ascochyta, Phoma and Phyllosticta have been recorded from spots on leaves and pods of soybean. Comparison of herbarium material, pathogenicity tests and in vitro studies have demonstrated that Phoma sojicola comb. nov. (syn. Ascochyta sojicola ) was predominantly involved as a pathogen of soybean. The diagnostic characters and history of this fungus and other hyaline-spored coelomycetes occurring on soybean are described.

Phoma-like fungi on soybeans

Abstract Numerous coelomycetous fungi classified in Ascochyta, Phoma and Phyllosticta, and lately established and/or re-classified genera and species, namely Boeremia and Peyronellaea have been recorded from spots on leaves and pods of soybeans. These rarely observed pathogens are cosmopolitan, ubiquitous species on diseased and dead plant materials, and define frequently as weak or opportunistic parasites. Based on the Genealogical Concordance Phylogenetic Species Recognition, the authors summarize the re-evaluation of the taxonomic status of Phoma sojicola (syn. Ascochyta sojicola) and Phyllosticta sojicola. Inspite of the former delimitation of Ph. sojicola based on small differences in morphological features, it has proved to be identical to Peyronellaea pinodella (syn. Phoma pinodella). Similarly, it was also confirmed that Ph. sojicola was identical to Boeremia exigua var. exigua (syn. Phoma exigua var. exigua). The authors and co-workers contributed to the identification of Phoma-like fungi by combined conventional and molecular methods. Protein-encoding genes (TEF1 and β-tubulin) were successfully applied within the Phoma genus to infer phylogenetic relationships.

Occurrence of Stone Fruit Yellows Phytoplasma Disease (Candidatus Phytoplasma prunorum) in Hungary and Central Europe

Plant diseases caused by phytoplasmas have an increasing importance all over the world for fruit growers. Lately, phytoplasma diseases occur on many fruit species and are responsible for serious losses both in quality and quantity for fruit production. Apricot phytoplasma disease (Candidatus Phytoplasma prunorum) was reported first from France in Europe in 1924. Then, the pathogen spread in all European apricot-growing areas. In 1992, the disease was identified in Hungary first. Based on the growers’ signals, serious damage of Ca. Phytoplasma prunorum (Seemuller and Schneider, International Journal of Systematic and Evolutionary Microbiology, 54, 2004, 1217–1226; formerly: European stone fruit yellows (ESFY) phytoplasma) could be observed in several stone fruit orchards in the famous apricot-growing area nearby the town of Gonc, northern Hungary. Field examinations were started in 2009 in the infested stone fruit plantations in Borsod-Abauj-Zemplen County, mainly in Gonc region, which is one of the most important apricot-growing areas in Hungary, named “Gonc Apricot-growing area”. Our goals were to diagnose the occurrence of Ca. Phytoplasma prunorum on stone fruits (especially on apricot) in the North Hungarian growing areas by visual diagnostics and to confirm data by laboratory polymerase chain reaction (PCR)-based examinations. All the 40 collected samples were tested in laboratory trials and in 22 samples from apricot, peach, cherry, sour cherry and wild plum were confirmed the presence of phytoplasma (ESFY). Field investigations were done in a western Romanian apricot plantation, and the presence of apricot phytoplasma disease was confirmed. It was the first finding that Ca. Phytoplasma prunorum occurred in the western part of Romania. On the basis of these observations, it seems evident that the notable losses caused by Ca. Phytoplasma prunorum is a new plant health challenge for fruit growers to manage, especially for apricot producers in Hungary and other central European countries.

Morphological and genetic differentiation among four pigment producing Indian species of Phoma (Saccardo, 1899)

A PCR-based technique, involving the random amplification of polymorphic DNA (RAPD), was used for assessing genetic relatedness among isolates of the genus Phoma. Randomly Amplified Polymorphic DNA (RAPD) revealed the presence of interspecific genetic variation among the pigment producing isolates of Phoma and has shown distinct phylogenetic cluster. The major objective of the study was to study the genetic variation, if any. Study was aimed to differentiate four pigment producing species of Phoma based on morphological studies and molecular markers in general and RAPD in particular. We found that the test species of Phoma can be very well differentiated using molecular markers. Phoma sorghina was differentiated from P. exigua, P. fimeti and P. herbarum. RAPD profiles of P. herbarum and P. fimeti has shown the maximum similarity, which indicates the genetic relatedness among these two species which were considered earlier as distinct species based on morphological observation.