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Motivation: The characterization of phylogenetic and functional diversity is a key element in the analysis of microbial communities. Amplicon-based sequencing of marker genes, such as 16S rRNA, is a powerful tool for assessing and comparing the structure of microbial communities at a high phylogenetic resolution. Because 16S rRNA sequencing is more cost-effective than whole metagenome shotgun sequencing, marker gene analysis is frequently used for broad studies that involve a large number of different samples. However, in comparison to shotgun sequencing approaches, insights into the functional capabilities of the community get lost when restricting the analysis to taxonomic assignment of 16S rRNA data. Results: Tax4Fun is a software package that predicts the functional capabilities of microbial communities based on 16S rRNA datasets. We evaluated Tax4Fun on a range of paired metagenome/ 16S rRNA datasets to assess its performance. Our results indicate that Tax4Fun provides a good approximation to functional profiles obtained from metagenomic shotgun sequencing approaches. [ABSTRACT FROM AUTHOR]

The vascular plant pathogen Verticillium dahliae colonizes the xylem fluid where only low nutrient concentrations are provided. Biosynthesis of the vitamin thiamine is connected to oxidative stress. The highly conserved VdThi4 protein is localized in fungal mitochondria and is required under vitamin B1 limiting conditions. Deletion of the corresponding VdTHI4 gene by Agrobacterium -mediated transformation resulted in strains which were impaired in growth on thiamine-free medium and could be rescued by additional vitamin supply or by complementation with the original gene after protoplastation. Furthermore, we show that VdThi4 increases fungal stress tolerance such as UV-damage or oxidative stress. The orthologous sti35 gene of Fusarium oxysporum , another vascular wilt fungus, was shown to be involved in stress response, however to be dispensable for pathogenicity on tomato. In contrast, VdTHI4 is required for fungal-induced tomato disease demonstrated by infection assays with a V. dahliae Δ VdTHI4 deletion strain which is still able to invade plants through the roots but is asymptomatic. Our results suggest remarkable differences between two vascular tomato pathogens where VdThi4 is required for pathogenicity of V. dahliae , whereas F. oxysporum still causes disease when the corresponding Sti35 protein is absent. [ABSTRACT FROM AUTHOR]

Amphidiploid fungal Verticillium longisporum strains Vl43 and Vl32 colonize the plant host Brassica napus but differ in their ability to cause disease symptoms. These strains represent two V. longisporum lineages derived from different hybridization events of haploid parental Verticillium strains. Vl32 and Vl43 carry same-sex mating-type genes derived from both parental lineages. Vl32 and Vl43 similarly colonize and penetrate plant roots, but asymptomatic Vl32 proliferation in planta is lower than virulent Vl43. The highly conserved Vl43 and Vl32 genomes include less than 1% unique genes, and the karyotypes of 15 or 16 chromosomes display changed genetic synteny due to substantial genomic reshuffling. A 20 kb Vl43 lineage-specific (LS) region apparently originating from the Verticillium dahliae-related ancestor is specific for symptomatic Vl43 and encodes seven genes, including two putative transcription factors. Either partial or complete deletion of this LS region in Vl43 did not reduce virulence but led to induction of even more severe disease symptoms in rapeseed. This suggests that the LS insertion in the genome of symptomatic V. longisporum Vl43 mediates virulence-reducing functions, limits damage on the host plant, and therefore tames Vl43 from being even more virulent., (© 2021 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.)