|Azeredo-espin, Ana maria|
Submitted to: Mycological Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/24/2008
Publication Date: 5/11/2008
Citation: Formighieri, E.F., Tiburcio, R.A., Armas, E.D., Shimo, H.M., Carels, N., Goes-Neto, A., Araujo, M.R., Cotomacci, C., Carazzolle, M.F., Thomazella, D.P., Sardinha-Pinto, N., Rincones, J., Digiampietri, L.A., Carraro, D.M., Azeredo-Espin, A., Reis, S.F., Deckman, A.C., Gramacho, K., Goncalves, M.S., Moura-Neto, J.P., Luciana, V.B., Meinhardt, L.W., Cascardo, J.C., Pereira, G.A. 2008. The phytopathogenic basidiomycete Moniliophthora perniciosa senesces and contains a kalilo-like plasmid stably integrated in its large mitochondrial genome. Mycological Research. http://apsjournals.apsnet.org/doi/pdf/10.1094/MPMI-21-7-0891. 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. The present study analyzed the mitochondrial genome sequence data of the fungal pathogen that causes WBD to develop an in-depth comparison with known mitochondrial sequence. This information provides insight into how this fungus functions and allows researchers mechanisms to develop new control measures. Plant pathologists, biologists and mycologists will benefit directly from this information.
Technical Abstract: In this work we show that the necrotrophic mycelia of the hemibiotrophic basidiomycete Moniliophthora perniciosa, the causal agent of the witches’ broom disease in Theobroma cacao, undergoes senescence, a feature that was associated with a decline in the content of mitochondrial DNA per cell. The mitochondrial genome of this phytopathogen was investigated. With 109,103 bp, it is the largest mitochondrial genome sequenced so far. It contains the 14 typical genes plus rps3, the two rRNA genes and 26 tRNA genes, which recognize codons for all amino acids. Except for ATP8, all typical genes are transcribed from the same DNA strand. The large genome size is related to a number of hypothetical genes and, most intriguing, with the presence of a kalilo-like mitochondrial plasmid, which is known to induce senescence in some fungal species. The plasmid sequence was not detected in an independent form and it seems to have been incorporated recently and in a stable manner into the mitochondrial genome of C. perniciosa. Although no direct connection has been established between senescence and the presence of this plasmid, analysis of local GC content and codon usage indicate that the genes associated to the plasmid could be active. We discuss the advantage of senescence to the life cycle of C. perniciosa and present a comprehensive analysis of its mitochondrial genome.