Low-Copy Genes in Terpenoid Metabolism: The Evolution and Expression of and Genes in Angiosperms.

Terpenoids are a diverse class of metabolites that impact plant metabolism in response to environmental cues. They are synthesized either via a predominantly cytosolic (MVA) pathway or a plastidic pathway (MEP). In , several enzymes from the MVA and MEP pathways are encoded by gene families, excluding and , which are single-copy genes. In this study, we assess the diversity, evolution and expression of and genes in selected angiosperms and in particular. Evolutionary analysis revealed that and underwent purifying selection, but the selection effect for was stronger than it was fo. Digital gene expression (DGE) profile analysis of six species revealed that expression levels of in flowers and roots were high, whereas for peak values were observed in leaves. In , both genes were highly expressed in flowers, and was upregulated in response to methyl jasmonate. DGE data were validated by assessing gene expression in selected organs, and by plants treated with hexanoic acid (Hx) using RT-qPCR. expression was upregulated in roots treated with Hx. was downregulated in leaves by Hx treatment in a genotype-specific manner, indicating a differential response to priming.