Isolation and characterization of a wound inducible phenylalanine ammonia‐lyase gene (LsPAL1) from Romaine lettuce leaves

Abstract

Phenylalanine ammonia‐lyase (PAL) catalyses the first step controlling the rate of phenylpropanoid metabolism. Wounding is a ubiquitous stress in nature and in the harvesting and preparation of fruits and vegetables that induces an increase in PAL activity, an accumulation of phenolic compounds and subsequent tissue browning. A wound‐inducible PAL gene (LsPAL1) was isolated from Romaine lettuce by RT‐PCR. The putative protein encoded by LsPAL1 is similar to predictive polypeptides sequences for other PALs. The kinetics of PAL mRNA accumulation is similar to those of induced PAL enzyme activity, with enzyme activity following mRNA accumulation by 12 h. Wound‐induced PAL transcripts accumulated in cells close to the wound sites. Tissue printing showed that PAL mRNA was associated with tissue next to the epidermis and vascular bundles. A heterologous PAL protein was expressed in E. coli and was found to show significant PAL activity.

Characterization of wound responsive genes in Aquilaria malaccensis

“…This delayed expression was consistent with findings on its homologs in lettuce and citrus, where PAL transcript levels were only elevated after 12 to 24 h after wounding treatment (Campos et al 2004;Kostenyuk et al 2002). AmPAL was upregulated at a fairly high level post 16-hour, which indicates its role in the phenylpropanoid pathway that is related to synthesis of secondary metabolites and lignin as plant general defense response.…”

Cloning of Phenylalanine Ammonia-lyase and its Role in Enzymatic Browning of Mung Bean Sprout during Cold Storage

“…In a preliminary experiment, more than 20 combinations of PAL sequences of such plants as Allium sativum (Tuan et al, 2010;Forward (F): 5´-TMCARG GMTACTCH GGCATMMG-3´, Reverse (R): 5´-GCGCTYTNSACRTGGTTNGT VA-3´), Euphorbia pulcherrima (Tao et al, 2011; 5´-GGAAAATTACTTCTCAAG-3´, R: 5´-TACATAGAAGGG ATTACA-3´), Lactuca sativa var. longifolia (Campos et al, 2004; F: …”

Inherent Quality and Safety of Watercress Grown in a Floating System Using <i>Bacillus subtilis</i>

“…Peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) activities were determined from 0.5 g of frozen tissue per sample. POD activity was determined as described by Nickel and Cunningham (1969) by the increase in absorbance, PPO activity was determined as described by Degl'Innocenti et al (2005), and PAL activity was determined as described by Campos et al (2004) and Degl'Innocenti et al (2005). Nitrate (NO 3 − ) was determined on the shoots using a refractometric kit (Merck Reflectoquant RQflex2 © ; Merck KGaA, Darmstadt, Germany), following the manufacturer's instructions from 10 g of frozen tissue per sample.…”