Abstract: Thiamine pyrophosphate (TPP)-dependent enzymes are present in all domains of life, which share a cofactor with TPP. However, a comprehensive analysis of TPP-dependent enzymes from sequenced genomes has not been reported and little is known about the evolutionary dynamics of this gene family in plants. In this study, the evolutionary relationships of the TPP-dependent enzymes were investigated by using a comprehensive genome-wide phylogenetic analysis. A total of 103 plant TPP-dependent enzyme sequences were identified in 16 plant species. Phylogenetic analyses suggest that these plant TPP-dependent genes fell into three major groups, acetolactate synthase, pyruvate dehydrogenase, and 2-hydroxyphytanoyl-CoA lyase. Our results showed fewer TPP-dependent genes in plants than that in other living organisms, with many types of genes lost during evolution possibly because they do not largely influence plant function. Within the plant kingdom, seed plants have more TPP genes compared to non-seed basal plants, which probably imply that seed plants developed more TPP genes to adapt to their environment. The present study provides important information for understanding the evolution and function of the TPP-dependent gene family in plants.

Key words: gene loss, genome-wide, phylogenetic analyses, TPP-dependent.