Newly identified sex chromosomes in the Sphagnum (peat moss) genome alter carbon sequestration and ecosystem dynamics

Abstract

Peatlands are crucial sinks for atmospheric carbon but are critically threatened due to warming climates. Sphagnum (peat moss) species are keystone members of peatland communities where they actively engineer hyperacidic conditions, which improves their competitive advantage and accelerates ecosystem-level carbon sequestration. To dissect the molecular and physiological sources of this unique biology, we generated chromosome-scale genomes of two Sphagnum species: S. divinum and S. angustifolium. Sphagnum genomes show no gene colinearity with any other reference genome to date, demonstrating that Sphagnum represents an unsampled lineage of land plant evolution. The genomes also revealed an average recombination rate an order of magnitude higher than vascular land plants and short putative U/V sex chromosomes. These newly described sex chromosomes interact with autosomal loci that significantly impact growth across diverse pH conditions. This discovery demonstrates that the ability of Sphagnum to sequester carbon in acidic peat bogs is mediated by interactions between sex, autosomes and environment.

Syntrichia ruralis: Emerging model moss genome reveals a conserved and previously unknown regulator of desiccation in flowering plants

“…The 305.19 Mb S. ruralis genome is similar in size to that of Bryum argenteum (292.04 Mb; Gao et al, 2023) and Pleurozium schreberi (318 Mb; Pederson et al, 2019). Of the two publicly-available Sphagnum genomes, one assembly is similar in size to S. ruralis , Sphagnum angustifolium at 367 Mb, while the other, Sphagnum divinum , is larger at 424 Mb (Healey et al, 2023). In sum, the size of the S. ruralis genome is within the range of other mosses, and there does not appear to be much of a pattern with respect to genome size in moss taxonomic groups as each are variable.…”

“…References: Syntrichia caninervis (Silva et al, 2020), Takakia lepidozioides (Hu et al, 2023), Physcomitrium patens (Lang et al, 2018; Rensing et al, 2020), Ceratodon purpureus , (Carey et al, 2021), Entodon seductrix (Yu et al, 2022), Fontinalis antipyretica (Yu et al, 2020), Calohypnum plumiforme (Mao et al, 2020), Pohlia nutans (Liu et al, 2022), Hypnum curvifolium (Yu et al, 2022). Bryum argenteum (Gao et al, 2023), Pleurozium schreberi (Pederson et al, 2019), Sphagnum angustifolium and Sphagnum divinum (Healey et al, 2023).…”

TheMarchantiapangenome reveals ancient mechanisms of plant adaptation to the environment

“…OXF, Anthoceros punctatus 86 , Ceratodon purpureus strain R40 (NCBI GCA_014871385.1), Marchantia paleacea 38 , Marchantia polymorpha ssp. ruderalis TAK1 (https://marchantia.info/download/MpTak_v6.1/), Physcomitrium patens 87 and Sphagnum fallax 88 ). Only the predicted genes partly supported by this protein database were kept using the https://github.com/Gaius-Augustus/BRAKER/blob/report/scripts/predictionAnalysis/selectSupportedSubsets.py script.…”

Characterization of UV sex chromosomes and synteny-guided phylogenomic resolution of subgenomes in Bryopsida mosses

“…To date several moss genomes have been published including two Dicranidae genomes: Ceratodon purpureus 5 and Syntrichia caninervis 6 , and six Bryidae genomes: Pleurozium schreberi 7 , Fontinalis antipyretica 8 , Calohypnum plumiforme 9 , Ceratodon purpureus 5 , Pohlia nutans 10 , Entodon seductrix and Hypnum curvifolium 11 , all of which belong to the class Bryopsida. Recently, two Sphagnum genomes, S. divinum and S. angustifolium, were released 12 . The sphagnum lineage diverged early in the radiation of mosses and has a common ancestor that is evolutionarily distant from the Bryopsida 2 .…”

“…It is generally acknowledged that the sex of the haploid gametophyte dominant bryophytes is determined by UV (U: female and V: male) sex chromosomes. The UV chromosomal sexdetermination system has recently been identi ed and characterized in the Sphagnum genomes 12 and for Ceratodon purpureus 5 , and the U-and V-linked genes reported in C. purpureus provided important markers to phylogenetically distinguish other Dicranidae and Bryidae U/V sex chromosomes.…”