Abstract
BACKGROUND: The WD40 repeat proteins are crucial components of eukaryotic genomes and contribute to a wide array of plant developmental processes and environmental interactions. However, the true extent of intraspecific WD40 diversity in plants is unclear. RESULTS: We defined a nearly complete species-wide pan-WD40ome in maize based on the published genome sequences of 26 nested association mapping (NAM) population founders. The pan-WD40ome largely saturated with inclusion of approximately 20 inbred lines, with about 95% of the pan-WD40ome being present in at least two founders. The architectural diversity of the WD40 domains, additional domains, and consequent spatial protein structures suggested the functional diversity of the maize pan-WD40ome. This finding was supported by significant associations between 87 WD40 genes and 19 agronomic, 3 kernel-quality, and 3 biotic-stress traits, as well as the multiple molecular pathways through which the trait-associated WD40 genes were predicted to function. In addition, WD40 genes exhibited abundant genomic variations among the NAM founders. Sequence analysis indicated that gene duplications and gene translocations caused by Helitron transposons may play important roles in the amplification of WD40 genes during the evolution of the maize WD40 gene family. CONCLUSIONS: In summary, this study provides a comprehensive framework for understanding the structural and functional diversity of the pan-WD40ome in maize and other agronomically important species with complex genomes, as well as excellent candidate genes/alleles for maize genetic improvement.