Evolutionary Profiling of Group II Pyridoxal-Phosphate-Dependent Decarboxylases 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 N 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 and syntelogs in (L.) Heynh., pepper ( L.), and tomato ( L.) pointed toward 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 () 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.