101 Dothideomycetes genomes: A test case for predicting lifestyles and emergence of pathogens

Dothideomycetes is the largest class of kingdom Fungi and comprises an incredible diversity of lifestyles, many of which have evolved multiple times. Plant pathogens represent a major ecological niche of the class Dothideomycetes and they are known to infect most major food crops and feedstocks for biomass and biofuel production. Studying the ecology and evolution of Dothideomycetes has significant implications for our fundamental understanding of fungal evolution, their adaptation to stress and host specificity, and practical implications with regard to the effects of climate change and on the food, feed, and livestock elements of the agro-economy. In this study, we present the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species. The availability of whole-genome data produced a high-confidence phylogeny leading to reclassification of 25 organisms, provided a clearer picture of the relationships among the various families, and indicated that pathogenicity evolved multiple times within this class. We also identified gene family expansions and contractions across the Dothideomycetes phylogeny linked to ecological niches providing insights into genome evolution and adaptation across this group. Using machine-learning methods we classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions. This can become a valuable tool for genome-based prediction of species lifestyle, especially for rarely seen and poorly studied species.

Compartmentation of 4,6-difluoro-5HT studied by nuclear magnetic resonance in normal and CHS bovine platelets

A platelet storage pool deficiency (SPD) is present in platelets from cattle with the Chediak-Higashi syndrome (CHS). The most plausible hypothesis for the SPD is that dense granule precursors are simply not formed in CHS megakaryocytes. There is, however, evidence that some recently acquired 5-hydroxytryptamine (5HT) is located in granules and that the granules have an acidic interior. To obtain a greater understanding of the processing of 5HT by SPD platelets, normal and CHS platelets were incubated with 4,6-difluoro-5HT and studied by 19F NMR at 188 mHz. Normal platelets contained 2 compartments for 4,6-difluoro-5HT as indicated by 2 well-developed resonances for each 19F. The resonances were unequal in magnitude. The predominant resonance broadened with lower temperatures and was absent in CHS bovine platelets; it was, therefore, the dense granule compartment. There was only 1 resonance for each 19F in CHS platelets. The chemical shift was identical to the minor resonance, or non-dense granule resonance, found in normal bovine platelets but the resonance width was increased, indicating that some non-dense granule 4,6-difluoro-5HT was in a more restricted environment within CHS platelets than it was in normal platelets.