A phenylalanine ammonia-lyase gene from melon fruit: cDNA cloning, sequence and expression in response to development and wounding
✍ Scribed by George Diallinas; Angelos K. Kanellis
- Publisher
- Springer
- Year
- 1994
- Tongue
- English
- Weight
- 728 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0167-4412
No coin nor oath required. For personal study only.
✦ Synopsis
Phenylalanine ammonia-lyase (PAL) is the first enzyme of phenylpropanoid biosynthesis involved in the synthesis of a multiplicity of plant natural products. We have isolated and characterized a nearly fulllength cDNA clone (pmPAL-1) corresponding to a melon fruit (Cucumis melo L. var. reticulatus) gene coding for a protein which is highly similar to PAL from other plants. Melon fruit PAL is transcriptionally induced both in response to fruit ripening and wounding. PAL gene expression follows the kinetics of expression of the ethylene biosynthetic genes during fruit development. In contrast, ethylene biosynthetic genes show different induction kinetics compared to PAL expression in response to wounding. Similar results have been found for two other genes coding for enzymes involved in flavonoid biosynthesis (chalcone synthase, CHS; chalcone isomerase, CHI). Our results imply that regulation of defense gene expression in melon is a co-ordinated process in response to both ethylene and an ethylene-independent wound signal.
PAL catalyses the first reaction in the general pathway of phenylpropanoid biosynthesis, the end products of which include lignin, aromatic compounds, flavonoid pigments, UV protectants, furanocoumarin and isoflavonoid phytoalexins and wound protectant, hydroxycinnamic acid esters . PAL activity responds to various external stimuli (light, wounding, fungal elicitor, infection) as well as to the developmental stage of plants . We have thus considered PAL expression as an ideal biochemical marker to investigate the complex interplay between ripening and wounding regulatory mechanisms in melon fruit.
In this work we describe the isolation and molecular characterization of a PAL cDNA clone
The nucleotide sequence data reported will appear in the EMBL, GenBank and DDBJ Nucleotide Sequence Databases under the accession number X76130.