Abstract
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gene sequences obtained from 15 different sites worldwide, of which twelve are already published studies and three are unpublished.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.
Highlights
Mangrove is a particular ecosystem located in the intertidal zone of marine coastal environments and estuarine margins
The diversity of Aromatic-ring-h ydroxylating dioxygenases (ARHD) genes involved in hydrocarbon biodegradation pathway in the mangrove sediment was determined and compared to ARHD gene sequences derived from other studies, in an attempt to elucidate patterns of biogeographic distribution of such enzymes at a global scale
The biogeographic distribution patterns of ARHD functional genes obtained from 15 different sites worldwide was investigated, in addition to their diversity at the functional and taxonomic levels
Summary
Mangrove is a particular ecosystem located in the intertidal zone of marine coastal environments and estuarine margins. Aromatic-ring-hydroxylating dioxygenases (ARHD) are multicomponent proteins responsible for the first step of Polycyclic Aromatic Hydrocarbons (PAHs) degradation (Lu, Zhang, & Fang, 2011) They consist of a catalytic component with a terminal ring- hydroxylating portion linked to a ferredoxin domain. Since there is a reasonable number of published studies that generated amplicons of ARHD genes, we decided to compile all of this information to try to understand the genetic relatedness among these sequences and their geographic distribution across the globe. For this purpose, sediment samples from an oil-impacted mangrove site was analyzed through the construction and sequencing of one α-ARHD gene library. The diversity of ARHD genes involved in hydrocarbon biodegradation pathway in the mangrove sediment was determined and compared to ARHD gene sequences derived from other studies, in an attempt to elucidate patterns of biogeographic distribution of such enzymes at a global scale
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
