Project description:Rhizoctonia solani Kühn is a soilborne basidiomycetous fungus that causes significant damage to many economically important crops. R. solani isolates are classified into 13 Anastomosis Groups (AGs) with interspecific subgroups having distinctive morphology, pathogenicity and wide host range. However, the genetic factors that drive the unique fungal pathology are still not well characterized due to the limited number of available annotated genomes. Therefore, we performed genome sequencing, assembly, annotation and functional analysis of 13 R. solani isolates covering 7 AGs and selected subgroups (AG1-IA, AG1-IB, AG1-IC, AG2-2IIIB, AG3-PT, AG3-TB, AG4-HG-I, AG5, AG6, and AG8). Here, we report a pangenome comparative analysis of 13 R. solani isolates covering important groups to elucidate unique and common attributes associated with each isolate, including molecular factors potentially involved in determining AG-specific host preference. Finally, we present the largest repertoire of annotated R. solani genomes, compiled as a comprehensive and user-friendly database, viz. RsolaniDB. Since 7 genomes are reported for the first time, the database stands as a valuable platform for formulating new hypotheses by hosting annotated genomes, with tools for functional enrichment, orthologs and sequence analysis, currently not available with other accessible state-of-the-art platforms hosting Rhizoctonia genome sequences.
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning.
Project description:A comparative genomic approach was used to identify large sequence polymorphisms among Mycobacterium avium isolates obtained from a variety of host species. DNA microarrays were used as a platform for comparing mycobacteria field isolates with the sequenced bovine isolate Mycobacterium avium subsp. paratuberculosis (Map) K10. ORFs were classified as present or divergent based on the relative fluorescent intensities of the experimental samples compared to Map K10 DNA. Map isolates cultured from cattle, bison, sheep, goat, avian, and human sources were hybridized to the Map microarray. Three large deletions were observed in the genomes of four Map isolates obtained from sheep and four clusters of ORFs homologous to sequences in the Mycobacterium avium subsp. avium (Maa) 104 genome were identified as being present in these isolates. One of these clusters encodes glycopeptidolipid biosynthesis enzymes. One of the Map sheep isolates had a genome profile similar to a group of Mycobacterium avium subsp. silvaticum (Mas) isolates which included four independent laboratory stocks of the organism traditionally identified as Maa strain 18. Genome diversity in Map appears to be mostly restricted to large sequence polymorphisms that are often associated with mobile genetic elements. Keywords: Comparative genomic hybridization
Project description:Methicillin-resistant Staphylococcus aureus clonal complex (CC) 398 has emerged from pigs to cause human infections in Europe and North America. We used a new 62-strain S. aureus microarray (SAM-62) to compare genomes of isolates from three geographical areas (Belgium, Denmark, and Netherlands) to understand how CC398 colonizes different mammalian hosts. The core genomes of 44 pig isolates and 32 isolates from humans did not vary. However, mobile genetic element (MGE) distribution was variable including SCCmec. Phi3 bacteriophage and human specificity genes (chp, sak, scn) were found in invasive human but not pig isolates. SaPI5 and putative ruminant specificity gene variants (vwb and scn) were common but not pig specific. Virulence and resistance gene carriage was host associated but country specific. We conclude MGE exchange is frequent in CC398 and greatest among populations in close contact. This feature may help determine epidemiological associations among isolates of the same lineage. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-120]
Project description:We performed whole genome sequencing on four isolates of C. jejuni, two of which were closely related phylogenetically while the remaining two were phylogenetically divergent. Genomes were closed and finished. 4-plex iTRAQ experiments were performed on the four isolates after growth on solid medium for a standard time. The research questions were: 1) how closely do the protein profiles match among the four isolates, and 2) were there any results consistent with differences in regulation among isolates.