Horizontal transfer of a ß-1,6-glucanase gene from an ancestral species of fungal endophyte to a cool-season grass host

Abstract

Molecular characterisation has convincingly demonstrated some types of horizontal gene transfer in eukaryotes, but nuclear gene transfer between distantly related eukaryotic groups appears to have been rare. For angiosperms (flowering plants), nuclear gene transfer events identified to date have been confined to genes originating from prokaryotes or other plant species. In this report, evidence for ancient horizontal transfer of a fungal nuclear gene, encoding a ß-1,6-glucanase enzyme for fungal cell wall degradation, into an angiosperm lineage is presented for the first time. The gene was identified from de novo sequencing and assembly of the genome and transcriptome of perennial ryegrass, a cool-season grass species. Molecular analysis confirmed the presence of the complete gene in the genome of perennial ryegrass. No corresponding sequence was found in other plant species, apart from members of the Poeae sub-tribes Loliinae and Dactylidinae. Evidence suggests that a common ancestor of the two sub-tribes acquired the gene from a species ancestral to contemporary grass-associated fungal endophytes around 9–13 million years ago. This first report of horizontal transfer of a nuclear gene from a taxonomically distant eukaryote to modern flowering plants provides evidence for a novel adaptation mechanism in angiosperms.

Horizontal gene transfer of Fhb7 from fungus underlies Fusarium head blight resistance in wheat

“…], revealing a naturally occurring transgenic food crop (32). However, there is little evidence for HGT events involving nuclear DNA transmission from fungi or other eukaryotes, and such transmission has been thought to be insignificant (33). Fundamentally, our results highlight the roles that FP-HGT has had in shaping plant genomes, which advances the knowledge on disease resistance gene evolution and opens a new avenue for the identification of plant resistance genes.…”

Fungus-originated genes in the genomes of cereal and pasture grasses acquired through ancient lateral transfer

“…4d). From short-read transcriptome sequencing data of the E + and E − perennial ryegrass seeds/young seedlings 23 , an increment of LpDUF3632 expression level was observed in E + seeds after a germination-treatment, although the expression levels of LpFTRL, EfM3.066060, and EfM3.028800 stayed low throughout the tested 10 days (Fig. 4e,f, and Supplementary Information 10).…”

Horizontal Gene Transfer and Endophytes: An Implication for the Acquisition of Novel Traits

“…The study performed de novo sequencing and assembly of the ryegrass genome and discovered the presence of the β-1,6-glucanase gene. Moreover, the transfer of β-1,6-glucanase gene from endophytic fungi to perennial ryegrass, suggested an evolutionary adaptation in angiosperms [27]. In the current perspective, similar studies are essential to elucidate the mechanism and importance of HGT in the evolution of plant-microbe associations.…”

“…Whole-genome sequencing of plants, namely Arabidopsis thaliana, Oryza sativa, Populus trichocarpa, and Sorghum bicolor revealed fewer HGT events, suggesting their less frequent occurrence. One remarkable example is the first reported HGT of the β-1,6-glucanase gene from endophytic fungi to grasses [27]. The study performed de novo sequencing and assembly of the ryegrass genome and discovered the presence of the β-1,6-glucanase gene.…”