科研之友
微信
新浪微博
Facebook
分享链接
摘要
Liverworts are rich in phenolic compounds, including flavonoids and the distinctive type of bisbibenzyls. The biosynthesis of both types of compounds is believed to involve the phenylpropanoid pathway. Phenylalanine ammonia-lyase (PAL) is thought to be the key enzyme in the biosynthesis of bisbibenzyls and flavonoids in liverworts. In this study, PAL (designated as PaPAL) was cloned and characterized from both the cDNA and genomic DNA of the liverwort Plagiochasma appendiculatum. The full-length cDNA sequence contains 2,202 bp and is predicted to encode a protein with 733 amino acids. Sequence alignment showed that PaPAL's predicted amino acid sequence shares more than 70 % identity with PAL sequences reported in public databases. The recombinant protein was heterologously expressed in Escherichia coli and exhibited high PAL activity, catalyzing the conversion of l-phenylalanine to trans-cinnamic acid. However, the enzyme exhibited lower activity in catalyzing the formation of p-coumaric acid from l-tyrosine. Additionally, when the thallus of P. appendiculatum was treated with abiotic stress inducers methyl jasmonate and abscisic acid, PaPAL expression was enhanced, thereby augmenting bisbibenzyl formation. These results suggest that PaPAL plays a key role in the early steps of bisbibenzyl biosynthesis and that abiotic stress can stimulate the expression of PaPAL, resulting in the accumulation of bisbibenzyls in the plant.
- 出版日期2014-5
- 单位山东大学
