Genome-wide identification and characterization of the Phenylalanine Ammonia-lyase (PAL) gene family in Medicago truncatula

Phenylalanine ammonia-lyase (PAL) catalyzes the rate-limiting step of phenylpropanoid biosynthesis in plants and supplies precursors for a variety of secondary metabolites, such as flavonoids, lignins and stilbenes. The first draft of the full Medicago truncatula genome assembly has been released. However it is observed that, the PAL gene family from Medicago truncatula (MtPAL genes) has not been characterized in detail. In this study, a comprehensive analysis of the Medicago truncatula PAL gene family is presented, including chromosomal locations, phylogenetic analyses, gene structures, three-dimensional (3D) structures and expression patterns. Six Medicago truncatula PAL genes that encode PAL proteins were identified in the Medicago truncatula genome. It was shown that MtPAL genes are distributed on four chromosomes. Dynamic expression patterns of M tPAL genes were observed in different tissues and abiotic stresses, suggesting that MtPAL genes may play important roles in the regulation of development and stress responses in Medicago truncatula.