Immunocytolocalization and relationship of Rhizoctonia α-glucans with potato α-glucanase activity

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

Mar del Plata. Argentina

Congreso; SAIB 43th Annual Meeting; 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

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, α-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 α-glucanolytic activity in plants.  Financiado por:  CONICET, UNMDP, CIC