Immunocytolocalization and relationship of Rhizoctonia á-glucans with potato á-glucanase activity.

WOLSKI E. A; MALDONADO S; DALEO G. R; ANDREU A. B

Mar del Plata, Argentina

Congreso; XLIII REUNION ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIONES EN BIOQUIMICA Y BIOLOGIA MOLECULAR (SAIB).; 2007

SOCIEDAD ARGENTINA DE INVESTIGACIONES EN BIOQUIMICA Y BIOLOGIA MOLECULAR (SAIB).

The wall interface between plants and pathogens plays an important role in their interaction. Studies about fungal cell walls are scarce and the results show the existence of a-1, 3-glucans in addition to ß-glucans. a-1, 3-glucans are not present in plant cell walls and a-glucanase activity in plants has not been described before. In a previous work, we purified an a-1, 3-glucan from a binucleated non-pathogenic Rhizoctonia (BNR) isolate, which induces plant defense responses. In order to study the architecture of the fungal cell wall, as well as the accessibility and localization of the a-glucan, we prepared an antibody against the a-1, 3-glucan and analyzed its localization by TEM. Immunolocalization showed the presence of the a-1, 3-glucan in the intercellular spaces and along the cell walls, mainly on the inner layers. This result and the presence of the a-glucan in liquid culture, where BNR was grown, confirmed that the glucan had been secreted. In addition, alpha-glucanase activity in potato sprouts was detected using cell wall glucans from the pathogenic isolate R. solani AG-3 as substrates. Our results suggest that the presence of a-1, 3-glucans could be related with the formation and integrity of cell wall and with plant-fungi interactions. This is the first report that describes alpha-glucanolytic activity in plants.