Diazotrophic bacteria in Guzmania monostachia (Bromeliaceae): hormonal signaling molecules and leaf tissue colonization
C. KLEINGESINDS (1), P. Mioto (1), R. Zuccarelli (2), M. Rodrigues (2), D. Demarco (2), M. Aidar (3), H. Mercier (2) (1) University of São Paulo, Brazil; (2) University of São Paulo, Brazil; (3) Instituto de Botânica de São Paulo, Brazil

Guzmania monostachia is an epiphytic tank-bromeliad with a well-recognized photosynthetic plasticity. Besides, it is suggested that interactions with microorganisms may also aid the nutrition of epiphytic bromeliads, but little is known about that. In the present study, two strains of diazotrophic bacteria (Pseudomonas sp. and Burkholderia sp.) previously isolated from G. monostachia leaves were labeled with GFP, and then inoculated separately into the tank of this bromeliad, to analyze their colonization patterns (by confocal microscopy) in coordination to the signaling mechanisms elicited by their inoculation (by measuring the endogenous levels of nitric oxide - NO, salicylic acid - SA, ethylene - ET and indol-3-acetic-acid - IAA) within the plant rosette. The results revealed the presence of both bacteria after 20 hours of inoculation in the trichomal cells and surrounding tissues inside the leaf bases. Although no variation was verified in ET and IAA contents following the inoculation, a significant increase in NO levels was observed along the younger leaves and in bases of intermediate leaves after 1h of the bacteria inoculation. Besides, higher AS content was detected after 120h of Burkholderia sp. inoculation in the bases of intermediate leaves. The results indicate that both bacteria entered the G. monostachia leaf bases via trichomes and elicited NO-mediated signaling mechanisms with specific patterns of spatial compartmentalization within the plant rosette.

Abstract Number: P16-454
Session Type: Poster