HortScience
(293) The PAL Gene Activity in Five Rosemary
Genotypes and Its Effect on the Production of
Rosmarinic Acid
1.
2.
3.
Hany M. El-Naggar1,
Paul E. Read1 and
Ayed Al-Abdallat2
-Author Affiliations
1
1.
University of Nebraska-Lincoln, Agronomy and Horticulture Dept., Lincoln, NE, 68503
2
2.
University of Nebraska-Lincoln, School of Biological Science, Lincoln, NE, 68588-0118
Abstract
Phenylalanine ammonia-lyase (PAL) enzyme is the most extensively studied enzyme in the phenylpropanoid
pathway. Studies on the biosynthesis of rosmarinic acid (RA) showed that the PAL enzyme catalyzes the initial step
of the phenylpropanoid pathway. The increase in RA content in plant tissues in vitro coincided with the increase in
PAL activity. The aim of this study was to investigate the activity of the gene responsible for the production of the
PAL enzyme in the five rosemary genotypes; this will give more understanding about the accumulation of
rosmarinic acid in the five rosemary genotypes. The genotypes were Majorca, Rosmarinus officinalis, Pine Scented,
Madeline Hill and APR. Northern blot hybridization between the PAL gene primer and the five genotypes' cDNA
showed bands at 300 bp in all the five genotypes for the PAL gene. The expression of the PAL gene was high in
genotypes Majorca,Rosmarinus officinalis, and Madeline Hill, while the expression was low in genotypes Pine
Scented and APR. It was expected that the genotypes having the highest PAL gene expression will produce the
highest amount of RA, but the highest genotype in PAL gene expression Madeline Hill had the lowest RA
production in their leaves. This could occur due to the tissue specific regulation inside plant tissues. Inside the callus
tissues, where the specific tissue regulation no longer exists, the RA was produced in repetitively large amounts in
genotypes with high PAL gene expression.
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