(Phakopsora Pachyrhizi) Oliveira, DM

XLIII Annual Meeting of SBBq Foz do Iguaçu, PR, Brazil, May 17th to 20th, 2014

Biological Activity Of Recombinant Pea Defensin Drr230a Towards Soybean Asian Rust (Phakopsora pachyrhizi)

Oliveira, D.M.1,2, Lacerda, A. F.2, Del Sarto, R. P.2, Vasconcelos, E.A.R.1,2, Silva, M.S.2, Godoy, C.V3, Seixas,C.D.S3, Grossi de Sá, M. F.2

1 FACIPLAC, Brasília, DF; 2 Embrapa Recursos Genéticos e Biotecnologia, EMBRAPA CENARGEN,Brasília, DF; 3 Embrapa Soja,Londrina, PR; Brazil

Introduction: Phakopsora pachyrhizi, the agent of soybean Asian rust is responsible for extensive losses in soybean production. The use the fungicides for control of this pathogen are extremely dangerous because are related various disorders in mammals, as well as damaging to the environment. To circumvent fungal infection plants produce diverse defense molecules, such cationic peptides named Defensins. In this context, plant defensins can play an important role in defense against diverse pathogens. Due to remarkably characteristic, these molecules have promising biotechnological applications on pathogen control. Material and methods: To evaluate the antifungal activity of Drr230a, the gene of pea (Pisum sativum) defensin, DRR230a was subcloned into the yeast expression vector pPICZαA® (Invitrogen Co.), and expressed in Pichia pastoris strain X33. Aliquots were collected at each 24 hours and analyzed on tricine-SDS-polyacrylamide gel electrophoresis and detected by Western bloting with anti-His antibody. rDrr230a was purified by using Immobilized Metal Affinity Chromatography (IMAC) to analyse the antifungal activity against P. pachyrhizi. The antifungal activity of rDrr230a was performed in two assays. The first assay to analyze inhibition of the P. pachyrhizi uredospore germination and second assay to analyze the disease severity caused in vivo by P. pachyrhizi in presence or absence of rDrr230a which the disease severity was evaluated daily for two weeks, by using a scale varying from 0% up to 100% severity. Results and discussion: rDrr230a at 3 µg/µl inhibited 100% of in vitro spore germination after 12h incubation. In vivo assays showed that rDrr230a application at 3 µg/µL resulted in no disease up to 14 days post inoculation. Conclusions: These results show the antimicrobial activity of the rDrr230a defensin against impacting soybean fungi and reveal promising application for biotechnological fungi infection control.

Key words: Phakopsora pachyrhizi , Defensin, Pichia pastoris. Supported by: EMBRAPA, UCB, CNPq, CAPES, FINEP.