An ecological, phenotypic and genomic survey of duckweeds with their associated aquatic environments in the United Kingdom

Abstract The duckweeds feature global distributions and diverse applications in phytoremediation and nutrition, as well as use in fundamental studies of development. Existing collections have minimal environmental data linked to natural habitats. Thus, there is a lack of understanding of natural variation in the context of native habitats. Here, a novel collection of 124 duckweed accessions from 115 sites across the United Kingdom were characterised by genome sequencing and ionomics. In nutrient-replete conditions all accessions hyperaccumulated P, K, Mg and Ca. Local but not large-scale associations were revealed between elemental composition of duckweed in common, replete conditions and native water profiles. Lemna minor was the most prevalent species in the UK, with a closely related hybrid L. japonica frequently found in waters with higher micronutrient concentrations. Invasive L. minuta was common in the southern and midland regions, but restricted in Scotland. Lemna accessions accumulated heavy metal contaminants typically together with macronutrients, suggesting phytoremediation potential, but some limitations as food. Furthermore, monitoring the ecological interactions between native, hybrid and invasive Lemna species should be ongoing in the interest of biodiversity. Competing Interest Statement The authors have declared no competing interest. Footnotes Competing Interests statement: The authors declare no competing interests. Symbols and abbreviations - ICP-MS - Inductively coupled plasma mass spectrometry. - SPME PTFE - Solid Phase Microextraction Polytetrafluoroethylene. - HDPE - High density polyethylene. - GRIS - Global Register of Introduced and invasive Species. - LOD - Limit of detection. - NCBI - National Centre for Biotechnology Information. - SRA - Sequence read archive. - dsDNA - Double stranded deoxyribonucleic acid. - GATK - Genome analysis toolkit. - SNPs - Single nucleotide polymorphisms. - 4FDS - Four-fold degenerate site. - MIS - Missingness. - MAF - Minor allele frequency. - PCA - Principal component analysis. - HAS - Hastings, UK. - COR - Cornwall, UK. - BRI - Bristol, UK. - NEW - Newport, UK. - ABE - Aberdeen, UK. - ELG - Elgin, UK. - GLA - Glasgow, UK. - LAN - Lancaster, UK. - BFD - Bradford, UK. - YOR - York, UK. - HUL - Hull, UK. - MID - Midlands, UK. - NCA - Newcastle, UK.