Morphological and molecular characterization of Colletotrichum coccodes isolated from pepper cultivated in Bulgaria and Macedonia

Colletotrichum coccodes has been recognized as one of the causal agents of pepper fruit anthracnose in Bulgaria. Recently, this species has been recorded in pepper fruits in Macedonia. In Bulgaria, the fungus has also been isolated from roots of premature senescent pepper plants but in Macedonia it has not been isolated yet. The purpose of the investigation was to make comparative morphological, cultural and molecular characterization of C. coccodes isolates obtained from pepper fruits and roots in Bulgaria and Macedonia. Additionally, a technique was applied to differentiate among the C. coccodes isolates obtained from roots and other microsclerotia-producing fungi. On the host tissue, C. coccodes developed acervular conidiomata with cup-shaped fruiting bodies accompanied with dark-pigmented, unbranched, thick-walled sterile hyphae called setae. A slimy mass of hyaline, straight, unicellular, fusiform conidia appeared on nutrient media. In a short time, numerous small dark globose setose microsclerotia emerged in the colony starting from its centre and distributing proportionally throughout agar plates. Two PCR primer sets were used to sequences of the ribosomal internal transcribed spacer (ITS1 and ITS2) regions. Single products of ~450 bp and ~350 bp were amplified by the genus-specific (Cc1F1/Cc2R1) and the species-specific primers (Cc1NF1/Cc2NR1), respectively. Morphological, cultural and molecular characterization of the isolates from roots and fruits showed that root rot and fruit anthracnose of pepper were caused by one and the same causal agent determined as C. coccodes. The isolates from roots showed rapid mycelial growth, gave rise to numerous minute microsclerotia and produced conidia only on SSPA. SSPA supported significantly more mycelium growth and sporulation than all other media tested and could be recommended for production of large quantity of conidia. No pattern of genetic variation associated with the organ or geographic origin of the isolates was determined

Pepper Diseases in Balkan Region

One of the most important problems affecting pepper production in the Balkan peninsula is the occurrence of common pathogens causing severe diseases and epidemics resulting in reduced and compromised yield. Phytophthora capsici, Botrytis cinerea, Sclerotinia sclerotiorum, Verticillium dahliae, Fusarium spp., Pseudomonas syringae pv. syringae, Xanthomonas vesicatoria, Pepper mild mottle virus (PMMV), Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), Alfalfa mosaic virus (AMV), Potato virus Y (PVY) etc. are among the most devastating and widely distributed pathogens. This region is also characterized with endemic, emerging or newly introduced pathogens threatening pepper production. In the last years new pepper fungal pathogens (Phomopsis capsici and several Colletotrichum spp.) were found in Bulgaria with increasingly frequency. In 2010 a SEE-ERA. NET project started combining the research efforts of seven scientific institutions from five Balkan countries (Albania, Bulgaria, Greece, Macedonia and Serbia). The strategic objectives of the project are: i) to explore Balkan biodiversity of Capsicum spp. in order to extract biotic stress resistant germplasm; ii) to update knowledge about the most economically important and emerging pathogens on Capsicum in the Balkan region and to form pathogen collection; iii) to develop database, concerning the pepper pathogen occurrence in the mentioned regions; iv) to identify areas at differing pathogen risk in the involved Balkan countries and to define risks related to introduction of new pathogen biotypes by trading. Adequate knowledge for pathogens is essential for the management of the diseases, caused by them and for solving problems in sustainable and conventional agriculture. First joint collecting expeditions have been carried out. Pathogens have been isolated, identified and characterized mainly at species level. Collections have been created and properly preserved in related institutes for further investigations concerning the race and strain specificity of the saved pathogens and host-pathogen interaction

Session 19 Plant-microbe interaction

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