Abstract:
Objective Genes of phenylalanine ammonia lyase (MiPAL) and polyphenol oxidase (MiPPO) syntheses inMangifera indica L. were identified with their regulation functions on fruit growth and development determined.
Methods Using bioinformatics methods and mango genomes, the PAL and PPO family members in the fruits were identified based on analyses of protein characteristics, phylogenetic relationship, gene structure, and promoter cis acting elements. Expressions of the identified genes during fruit development were determined by transcriptome analysis.
Results Ten PALs and onePPO in the mangos were identified. They were stable, hydrophilic proteins located mainly in the chloroplasts. Being a woody plant, these genes are phylogenetically in a same subgroup of 4 PAL and PPO categories. The sequences of 25% of MiPALs lacked introns, and that of MiPPO without intron at all. The 10 MiPALs were distributed in 5 chromosomes and one fragment with 11 pairs of segmental duplication genes and 7 tandem duplication genes. Located in chromosome Chr12, MiPPO was homologous to PPO13 in Populus tomentosa. The cis acting elements in the promoters of MiPAL and MiPPO contained those of growth, development, and hormone and stress responses expressed in an inducible pattern. MiPALs were highly expressed in the fruits at both young and mature stages, whereas MiPPO only at maturation.
Conclusion With the information obtained, further exploration on the molecular regulatory mechanisms and biological functions of polyphenol accumulation in mango pulp was in order.