RESUMEN
Aromatic hydrocarbons (AH), such as polycyclic aromatic hydrocarbons, are compounds largely found in nature. Aromatic-ring-hydroxylating dioxygenases (ARHD) are proteins involved in AH degradation pathways. We used ARHD functional genes from an oil-impacted mangrove area and compared their diversity with other sites around the world to understand the ARHD biogeographic distribution patterns. For this, a comprehensive database was established with 166 operational protein families (OPFs) from 1,758 gene sequences obtained from 15 different sites worldwide, of which twelve are already published studies and three are unpublished. Based on a deduced ARHD peptide sequences consensus phylogeny, we examined trends and divergences in the sequence phylogenetic clustering from the different sites. The taxonomic affiliation of the OPF revealed that Pseudomonas, Streptomyces, Variovorax, Bordetella and Rhodococcus were the five most abundant genera, considering all sites. The functional diversity analysis showed the enzymatic prevalence of benzene 1,2-dioxygenase, 3-phenylpropionate dioxygenase and naphthalene 1,2-dioxygenase, in addition to 10.98% of undefined category ARHDs. The ARHD gene correlation analysis among different sites was essentially important to gain insights on spatial distribution patterns, genetic congruence and ecological coherence of the bacterial groups found. This work revealed the genetic potential from the mangrove sediment for AH biodegradation and a considerable evolutionary proximity among the dioxygenase OPFs found in Antarctica and South America sites, in addition to high level of endemism in each continental region.
Asunto(s)
Bacterias/enzimología , Dioxigenasas/genética , Variación Genética , Hidrocarburos Aromáticos/metabolismo , Microbiota , Filogeografía , Plantas/microbiología , Bacterias/clasificación , Dioxigenasas/metabolismo , HumedalesRESUMEN
NEP1 (necrosis- and ethylene-inducing peptide 1)-like proteins (NLPs) have been identified in a variety of taxonomically unrelated plant pathogens and share a common characteristic of inducing responses of plant defense and cell death in dicotyledonous plants. Even though some aspects of NLP action have been well characterized, nothing is known about the global range of modifications in proteome and metabolome of NLP-treated plant cells. Here, using both proteomic and metabolomic approaches we were able to identify the global molecular and biochemical changes in cells of Nicotiana benthamiana elicited by short-term treatment with MpNEP2, a NLP of Moniliophthora perniciosa, the basidiomycete responsible for the witches' broom disease on cocoa (Theobroma cacao L.). Approximately 100 protein spots were collected from 2-DE gels in each proteome, with one-third showing more than twofold differences in the expression values. Fifty-three such proteins were identified by mass spectrometry (MS)/MS and mapped into specific metabolic pathways and cellular processes. Most MpNEP2 upregulated proteins are involved in nucleotide-binding function and oxidoreductase activity, whereas the downregulated proteins are mostly involved in glycolysis, response to stress and protein folding. Thirty metabolites were detected by gas spectrometry (GC)/MS and semi-quantified, of which eleven showed significant differences between the treatments, including proline, alanine, myo-inositol, ethylene, threonine and hydroxylamine. The global changes described affect the reduction-oxidation reactions, ATP biosynthesis and key signaling molecules as calcium and hydrogen peroxide. These findings will help creating a broader understanding of NLP-mediated cell death signaling in plants.