En metagenomisk studie av lavsymbiosens bestandsdelar

Tidsperiod: 2017-01-01 till 2017-03-06

Projektledare: Toby Spribille

Finansiär: Vetenskapsrådet

Bidragstyp: Bidrag för anställning eller stipendier

Budget: 3 600 000 SEK

Lichen research has advanced since the 1860s to recognize the multiple origins of lichens, the relationships of their fungal components to pathogenic fungi, andthe open nature of the symbiosis with photosynthesizing partners. However, apparent discrepancies between symbiont genotypes and the lichen phenotype, and the extreme difficulty in achieving the latter in vitro, suggest lichens may more more than the sum of two parts. Indeed, recent metagenomic studieshave identified three, not two, eukaryotic components to be constantly present in natural macrolichens. Specifically, hitherto undetected basidiomycetous yeasts have been foundin addition to the known ascomycete by DNA sequencing and fluorescent imaging. In the present study I will map of lichen yeast occurrence in some of the globally most importantmacrolichen groups and relatedcrust-forming species. Iwill test threehypotheses: one, that the transition from crust lichens to macrolichens in the primary ascomycete fungus was accompanied by acquisition of yeasts in the symbiosis; two, that acquisition of specific guilds of yeasts is correlated with adoption of distinct body plans such as leafy, dorsiventral thalli or cupped vertical structures; and three, that the transition from free-living to symbiotic state in yeasts was associated with changes in carbohydrate-active enzyme composition that involved specialization on exogenous ascomycete substances.