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Summary White oak (Quercus alba) is an abundant forest tree species across eastern North America that is ecologically, culturally, and economically important.We report the first haplotype‐resolved chromosome‐scale genome assembly ofQ. albaand conduct comparative analyses of genome structure and gene content against other published Fagaceae genomes. We investigate the genetic diversity of this widespread species and the phylogenetic relationships among oaks using whole genome data.Despite strongly conserved chromosome synteny and genome size acrossQuercus, certain gene families have undergone rapid changes in size, including defense genes. Unbiased annotation of resistance (R) genes across oaks revealed that the overall number of R genes is similar across species – as are the chromosomal locations of R gene clusters – but, gene number within clusters is more labile. We found thatQ. albahas high genetic diversity, much of which predates its divergence from other oaks and likely impacts divergence time estimations. Our phylogenetic results highlight widespread phylogenetic discordance across the genus.The white oak genome represents a major new resource for studying genome diversity and evolution inQuercus. Additionally, we show that unbiased gene annotation is key to accurately assessing R gene evolution inQuercus.
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Kingdom-wide analysis of the evolution of the plant type III polyketide synthase superfamily
The emergence of type III polyketide synthases (PKSs) was a prerequisite for the conquest of land by the green lineage.Within the PKS superfamily, chalcone synthases (CHSs) provide the entry point reaction to the flavonoid pathway, while LESS ADHESIVE POLLEN 5 and 6 (LAP5/6) provide constituents of the outer exine pollen wall. To study the deep evolutionary history of this key family, we conducted phylogenomic synteny network and phylogenetic analyses of whole-genome data from 126 species spanning the green lineage including Arabidopsis thaliana, tomato (Solanum lycopersicum),and maize (Zea mays). This study thereby combined study of genomic location and context with changes in gene sequen-ces. We found that the two major clades, CHS and LAP5/6 homologs, evolved early by a segmental duplication event priorto the divergence of Bryophytes and Tracheophytes. We propose that the macroevolution of the type III PKS superfamily isgoverned by whole-genome duplications and triplications. The combined phylogenetic and synteny analyses in this studyprovide insights into changes in the genomic location and context that are retained for a longer time scale with more re-cent functional divergence captured by gene sequence alterations.
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- PAR ID:
- 10218854
- Date Published:
- Journal Name:
- Plant physiology
- ISSN:
- 0079-2241
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/plphys/kiaa086
