Kingdom-wide analysis of the evolution of the plant type III polyketide synthase superfamily.

Thomas Naake,Sebastian Proost,Hiroshi A Maeda,Takayuki Tohge,Alisdair R Fernie

doi:10.1093/plphys/kiaa086

Abstract

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 sequences. We found that the two major clades, CHS and LAP5/6 homologs, evolved early by a segmental duplication event prior to the divergence of Bryophytes and Tracheophytes. We propose that the macroevolution of the type III PKS superfamily is governed by whole-genome duplications and triplications. The combined phylogenetic and synteny analyses in this study provide insights into changes in the genomic location and context that are retained for a longer time scale with more recent functional divergence captured by gene sequence alterations.

Highlights

During plant evolution, the number of specialized metabolites and the enzymes responsible for their synthesis exploded (Weng et al, 2012; Moghe and Last, 2015)
We found that the two major clades, chalcone synthases (CHSs) and LESS ADHESIVE POLLEN 5 and 6 (LAP5/6) homologs, evolved early by a segmental duplication event prior to the divergence of Bryophytes and Tracheophytes
We provide evidence that the evolution of the type III polyketide synthases (PKSs) superfamily is governed by whole-genome duplication (WGD) and triplication (WGT) events following the emergence of the LAP and CHS clades

Summary

Introduction

The number of specialized metabolites and the enzymes responsible for their synthesis exploded (Weng et al, 2012; Moghe and Last, 2015). The number of protein folds, remained restricted (Chothia and Lesk, 1986; Weng et al, 2012). This is likely because novel biosynthetic pathways generally originate by gene duplication events and/or by functional divergence of existing genes (Moghe and Last, 2015).

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Results

Conclusion