Evolutionary profiling of group II PLPdependent decarboxylase gene family suggests expansion and functional diversification of histidine decarboxylases in tomato

Pyridoxal phosphate (PLP)-dependent enzymes are one of the most important enzymes involved in plant nitrogen metabolism. Here, we explored the evolution of group II PLP-dependent decarboxylases (PLP_deC), including aromatic L-amino acid decarboxylase, glutamate decarboxylase and histidine decarboxylase in the plant lineage. Gene identification analysis revealed a higher number of genes encoding PLP_deC in higher plants than in lower plants. Expression profiling of PLP_deC orthologs/syntelogs in Arabidopsis, pepper and tomato pointed towards conserved as well as distinct roles in developmental processes such as fruit maturation and ripening and abiotic stress responses. We further characterized a putative promoter of tomato ripening-associated gene (SlHDC10) operating in a complex regulatory circuit. Our analysis provides a firm basis for further in-depth exploration of the PLP_deC gene family, particularly in the economically important Solanaceae family. Page 2 of 40 The Plant Genome Accepted paper, posted 09/02/2015. doi:10.3835/plantgenome2015.07.0057