Fungi between extremotolerance and opportunistic pathogenicity on humans

Numerous agents of infections in humans and other mammals are found among fungi that are able to survive extreme environmental conditions and to quickly adapt to novel habitats.Nevertheless,the relationship between opportunistic potential and polyextremotolerance was not yet studied systematically in fungi.Here,the link between polyextremotolerance and opportunistic pathogenicity is shown in a kingdom-wide phylogenetic analysis as a statistically significant co-occurrence of extremotolerance(e.g.osmotolerance and psychrotolerance)and opportunism at the level of fungal orders.In addition to extremotolerance,fungal opportunists share another characteristic—an apparent lack of specialised virulence traits.This is illustrated by a comparative genomic analysis of 20 dothideomycetous and eurotiomycetous black fungi.While the genomes of specialised fungal plant pathogens were significantly enriched in known virulence-associated genes that encode secreted proteases,carbohydrate active enzyme families,polyketide synthases,and non-ribosomal peptide synthetases,no such signatures were observed in human opportunists.Together the presented results have several implications.If infection of human hosts is a side effect of fungal stress tolerance and adaptability,the human body is most likely neither the preferred habitat of such species,nor important for their evolutionary success.This defines opportunism as opposed to pathogenicity,where infection is advantageous for the species’fitness.Since opportunists are generally incapable of the host-to-host transmission,any host-specific adaptations are likely to be lost with the resolution of the infection,explaining the observed lack of specialised virulence traits.In this scenario opportunistic infections should be seen as an evolutionary dead end and unlikely to lead to true pathogenicity.

The long non-coding RNA DANA2 positively regulates drought tolerance by recruitingERF84 to promote JMJ29-mediated histone demethylation

Tens of thousands of long non-coding RNAs have been uncovered in plants,but few of them have been comprehensively studied for their biological function and molecular mechanism of their mode of action.Here,we show that the Arabidopsis long non-coding RNA DANA2 interacts with an AP2/ERF transcription factor ERF84 in the cell nucleus and then affects the transcription of JMJ29 that encodes a Jumonji C domain-containing histone H3K9 demethylase.Both RNA sequencing(RNA-seq)and genetic analyses demonstrate that DANA2 positively regulates drought stress responses through JMJ29.JMJ29 positively regulates the expression of ERF15 and GOLS2 by modulation of H3K9me2 demethylation.Accordingly,mutation of JMJ29 causes decreased ERF15 and GOLS2 expression,resulting in impaired drought tolerance,in agreement with drought-sensitive phenotypes of dana2 and erf84 mutants.Taken together,these results demonstrate that DANA2 is a positive regulator of drought response and works jointly with the transcriptional activator ERF84 to modulate JMJ29 expression in plant response to drought.