INTRARADICAL FUNGI ASSOCIATED TO VACCINIUM PLANTATIONS IN PATAGONIA ARGENTINA

BRUZONE MA. CLARA, MARIÑO JAVIER, FONTENLA SONIA

Pucón

Workshop; 3rd International Workshop: Advances in Science and Technology of Bioresources; 2011

Universidad de la Frontera

Ericaceous plants form root-fungus associations mainly with ericoid mycorrhizal fungi and some with dark septate endophytes. Mycorrhizal symbiosis plays a significant role in the life of these plants because they enhance host fitness in several ways that include improved nutrition. Fungi that form this type of associations usually can be cultivated axenically and identified by morphological and molecular methods. Blueberries (Vaccinium) belong to the Ericaceae family, which includes important commercial cultivated plants. In the past years it has increased its production and economic importance in South America, especially in Chile and Argentina. Paralel 42 (Northwest Patagonia) is known for its production of different kind of berries and Vaccinium cultivated area has been increasing notably, with economical and social repecussions. Interactions of intraradical microorganisms are low studied and their study would result in improvement of the production of this particular plant. The aim of this work was to isolate and identify intraradical fungi associated with cultivated Vaccinium species of Patagonia Argentina. Six individuals of two blueberry species, Vaccinium corymbosum (Highbush) and Vaccinium ashei (Rabbiteye) were sampled in November 2010 in a cultivation situated in El Hoyo- Comaraca del Paralelo 42 – Chubut - Argentina. Fine roots were collected, surface sterilized and 0,5 cm fragments were cultivated in Malt Agar 2%. All slow growing fungi, that clearly grew from the root fragments, were isolated into individual culture and grouped by morphological similarity. Representatives of the different groups were molecularly identified by sequencing rDNA ITS region amplified by primers ITS1F and ITS4, and compared with international sequence database (NCBI). Sixty pure cultures were obtained, and 34 were sequenced. Fifty nine porcent of the isolation were identified. These included dark septate endophyte species (Phialocephala fortinii, Leptodontidium orchidicola), as well as some other fungi species that are considered saprobes or pathogens (Neonectria radicicola, Paraphoma chrysanthemicola, Trichocladium opacum, Cryprosporiopsis ericae). Thirty five percent couldn´t be assigned a species, between these there are some isolates that are related to already species already described as ericoid mycorrhizal fungi. Some of the isolations that have been identified are possible ericoid mycorrhizal fungi and dark septate endophytes. This will be confirmed with re-synthesis in vitro experiments, to identify which of these isolations are true mycorrhizal fungi and evaluate their skills as plant growing promoters. This study shows preliminar results in Vaccinium plantations in Patagonia Argentina and is one of the first molecular study of endophyte species associated with this type of plants in Argentina. This work is a part of a PhD investigation project. Acknoledgement: This work was partially financed by grants B143 (Universidad Nacional del Comahue) and PICT 22200 (ANPCyT). The author has a fellowship of CONICET.