Extreme genome diversity and cryptic speciation in a harmful algal bloom forming eukaryote

ABSTRACT:

Harmful algal blooms (HABs) of the toxic haptophyte Prymnesium parvum are a recurrent problem in many inland and estuarine waters around the world. Strains of P. parvum vary in the toxins they produce and in other physiological traits associated with HABs, but the genetic basis for this variation is unknown. To investigate genome diversity in this morphospecies, we generated genome assemblies for 15 phylogenetically and geographically diverse strains of P. parvum including Hi-C guided, near-chromosome level assemblies for 2 strains. Comparative analysis revealed considerable DNA content variation between strains, ranging from 115 to 845 Mbp. Strains included haploids, diploids and polyploids, but not all differences in DNA content were due to variation in genome copy number. Haploid genome size between strains of different chemotypes differed by as much as 243 Mbp. Syntenic and phylogenetic analyses indicate that UTEX 2797, a common laboratory strain from Texas, is a hybrid that retains 2 phylogenetically distinct haplotypes. Investigation of gene families variably present across strains identified several functional categories associated with metabolic and genome size variation in P. parvum including genes for the biosynthesis of toxic metabolites and proliferation of transposable elements. Together, our results indicate that P. parvum is comprised of multiple cryptic species. These genomes provide a robust phylogenetic and genomic framework for investigations into the eco-physiological consequences of the intra- and inter-specific genetic variation present in P. parvum and demonstrate the need for similar resources for other HAB-forming morphospecies.

INSTRUMENT(S): Liquid Chromatography MS - positive - reverse phase

SUBMITTER: Timothy R Fallon 

PROVIDER: MTBLS5893 | MetaboLights | 2023-04-26

REPOSITORIES: MetaboLights