Submitted to: Mycological Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2007
Publication Date: 2/11/2007
Citation: Garcia, O., Macedo, J., Tiburcio, R., Zaparoli, G., Bittencourt, L.M., Ceita, G., Rincones, J., Micheli, F., Gesteira, A., Mariano, A., Schiavinato, M.A., Medrano, F., Meinhardt, L.W., Pereira, G.A., Cascardo, J.C. 2007. Characterization of Necrosis and Ethylene inducing Proteins (NEP) in the Basidiomycete Moniliophthora perniciosa, the Causal Agent of Witches’ Broom in Theobroma cacao. Mycological Research. 111:443-455. Interpretive Summary: Research into diseases of cacao is important to the USA economy because cacao is the raw material for the production of chocolate and the chocolate industry is one of the main consumers of US grown dairy, nuts, oils and sugar products. Fungal diseases such as Witches’ Broom Disease (WBD) of cacao have devastated cacao production in much of the Western Hemisphere. WBD is caused by the fungus Moniliophthora perniciosa. In the present study we identified and analyzed Necrosis and Ethylene inducing Proteins (MpNEPs) from M. perniciosa and showed that they could have a direct effect during the disease. This information provides insight into how this fungus functions and provides researchers mechanisms to develop new control measures. Plant pathologists, biologists and mycologists will benefit directly from this information.
Technical Abstract: The hemibiotrophic basidiomycete Moniliophthora perniciosa causes witches’ broom disease of Theobroma cacao. Analysis of the M. perniciosa draft genome led to the identification of three putative genes encoding Necrosis and Ethylene inducing Proteins (MpNEPs), which are apparently located on the same chromosome. MpNEP1 and 2 have highly similar sequences and are able to induce necrosis and ethylene emission in tobacco and cacao leaves. MpNEP1 is expressed in both biotrophic and saprotrophic mycelia, the protein behaves as an oligomer in solution and is very sensitive to temperature. MpNEP2 is expressed mainly in biotrophic mycelia, is present as a monomer in solution at low concentration (less than 40 micro Molar) and is able to recover necrosis activity after boiling. These differences indicate that similar NEPs can have distinct physical characteristics and suggest possible complementary roles during the disease development for both proteins. This is the first report of NEP1-like proteins in a basidiomycete.