Clément Gilbert, Florian Maumus

Genome Biology and Evolution, evac141, 26 September 2022

 https://doi.org/10.1093/gbe/evac141

Abstract

The extent to which horizontal gene transfer (HGT) has shaped eukaryote evolution remains an open question. Two recent studies reported four plant-like genes acquired through two HGT events by the whitefly Bemisia tabaci, a major agricultural pest (Lapadula et al. 2020; Xia et al. 2021). Here, we uncovered a total of 49 plant-like genes deriving from at least 24 independent HGT events in the genome of the MEAM1 whitefly. Orthologs of these genes are present in three cryptic B. tabaci species, they are phylogenetically nested within plant sequences, and expressed and under purifying selection. The predicted functions of these genes suggest that most of them are involved in plant-insect interactions. Thus, substantial plant-to-insect HGT may have facilitated the evolution of B. tabaci towards adaptation to a large host spectrum. Our study shows that eukaryote-to-eukaryote HGT may be relatively common in some lineages and it provides new candidate genes that may be targeted to improve current control strategies against whiteflies.

See https://academic.oup.com/gbe/advance-article/doi/10.1093/gbe/evac141/6717574?login=false

Figure 2 – Phylogenetic relationships of potential plant-derived Bemisia tabaci genes. Phylogenetic 6 trees showing the Bta06453 cluster, annotated as delta fatty acid desaturase family (A) and the 7 Bta14885 cluster, annotated as beta-(1,2)-xylosyltransferase family (B). Each tree is inferred from the 8 multiple sequence alignment of the cluster representative sequence with its homologs found across 9 Aleyrodidae proteins and Uniref90 proteins from eukaryotes, prokaryotes and viruses. The labels for 10 Uniref90 proteins are either species names or the names of the first taxonomic level comprising all the 11 proteins of a specific Uniref90 cluster. The SSA-ECA proteins are labelled as « Ssa ». In (A), the labels of 12 the B. tabaci proteins present in the FAD genomic hotspots found in the MEAM1 and SSA-ECA genomes 13 are in bold and the Trialeurodes vaporariorum protein is labelled as “Tv”. The bootstrap values above 14 70% are indicated as magenta disks. The color legend indicating the taxonomy of proteins is indicated 15 inset. For the ease of representation, the trees are presented in a circular mode rooted at midpoint