Project description:Mannitol is a polyol that occurs in a wide range of living organisms, where it fulfills different physiological roles. In particular, mannitol can account for as much as 20 to 30% of the dry weight of brown algae and is likely to be an important source of carbon for marine heterotrophic bacteria. Zobellia galactanivorans (Flavobacteriia) is a model for the study of pathways involved in the degradation of seaweed carbohydrates. Annotation of its genome revealed the presence of genes potentially involved in mannitol catabolism, and we describe here the biochemical characterization of a recombinant mannitol-2-dehydrogenase (M2DH) and a fructokinase (FK). Among the observations, the M2DH of Z. galactanivorans was active as a monomer, did not require metal ions for catalysis, and featured a narrow substrate specificity. The FK characterized was active on fructose and mannose in the presence of a monocation, preferentially K(+). Furthermore, the genes coding for these two proteins were adjacent in the genome and were located directly downstream of three loci likely to encode an ATP binding cassette (ABC) transporter complex, suggesting organization into an operon. Gene expression analysis supported this hypothesis and showed the induction of these five genes after culture of Z. galactanivorans in the presence of mannitol as the sole source of carbon. This operon for mannitol catabolism was identified in only 6 genomes of Flavobacteriaceae among the 76 publicly available at the time of the analysis. It is not conserved in all Bacteroidetes; some species contain a predicted mannitol permease instead of a putative ABC transporter complex upstream of M2DH and FK ortholog genes.

| S-EPMC4325148 | biostudies-literature

SeqNeth Pilot ENA datahub

Project description:SeqNeth Pilot ENA datahub

| PRJEB48256 | ENA

Complete genome of the Medicago anthracnose fungus, Colletotrichum destructivum, reveals a mini-chromosome-like region within a core chromosome.

Project description:Colletotrichum is a large genus of fungal phytopathogens that cause major economic losses on a wide range of crop plants throughout the world. These pathogenes vary widely in their host specificity and may have either broad or narrow host ranges. Here, we report the first complete genome of the alfalfa (Medicago sativa) pathogen, Colletotrichum destructivum, which will facilitate the genomic analysis of host adaptation and comparison with other members of the Destructivum clade. We identified a specific 1.2Mb region within chromosome 1 displaying all the hallmarks of fungal accessory chromosomes, which may have arisen through the integration of a mini-chromosome into a core chromosome and possibly linked with the pathogenicity of this fungus. We show this region is also a focus for chromosomal rearrangements, which may contribute to generating genetic diversity for adaptive evolution. Finally, we report infection by this fungus of the model legume, Medicago truncatula, providing a novel pathosystem for studying fungal-plant interactions.

2023-12-18 | GSE246592 | GEO

Zobellia galactanivorans strain:Dsij

Project description:Marine bacterium that produces agarase and carageenanase

| PRJNA16099 | ENA