biologia plantarum

Biologia plantarum 59:298-304, 2015 | DOI: 10.1007/s10535-015-0493-2

Characterization of genes coding phenylalanine ammonia lyase and chalcone synthase in four Pogostemon cablin cultivars

S. Zeng¹, P. Ouyang², X. Mo², Y. Wang^1,3,*

¹ Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, P.R. China

² Guangdong Food and Drug Vocational College, Guangzhou, P.R. China

³ Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei, P.R. China

Pogostemon cablin (Blanco) Benth is a medicinal plant rich in terpenoids and flavonoids. Currently, the molecular mechanism of flavonoid biosynthesis in P. cablin remains unclear. In this study, three copies of the phenylalanine ammonia lyase (PAL) gene designated as PcPAL1 - PcPAL3, one copy of the chalcone synthase (CHS) gene referred to as PcCHS, and four copies of the CHS-like gene referred to as PcCHSL1 - PcCHSL4 were isolated from P. cablin. PcPAL1, PcPAL2, and PcPAL3 comprised 2 136, 2 136, and 2 148 bp full-length open reading frames (ORFs) encoding 711, 711, and 715 amino acids, respectively. PcCHS, PcCHSL1, PcCHSL2, PcCHSL3, and PcCHSL4 contained 1 173, 1 176, 1 179, 1 173, and 1 170 bp ORFs encoding 390, 391, 392, 390, and 389 amino acids, respectively. A phylogenetic analysis indicates that PcPAL2 was closer to PcPAL3 than PcPAL1, and that PcCHS was clustered with other plant CHS genes but independently to the PcCHSLs subgroup. A sequence analysis shows that PcCHSLs diverged in functional residues when compared to plant CHSs including PcCHS, suggesting that PcCHSLs may be divergent in tertiary structures. A quantitative reverse-transcription polymerase chain reaction analysis indicates that the expression profiles of PcPALs, PcCHS, and PcCHSLs in leaves and stems differed among four cultivars. Our results suggest that divergence in sequence and expression profiles of the tested genes may contribute to the diversity in flavonoids among the four cultivars.

Keywords: CHS; CHS-like; flavonoids; PAL; phylogenetic tree

Subjects: phenylalanineammonia lyase; chalcone synthase; gene expression; phylogenetic tree; leaf age; protein model

Received: June 26, 2014; Revised: September 26, 2014; Accepted: October 1, 2014; Published: June 1, 2015  Show citation