Plant Molecular Biology

, Volume 30, Issue 4, pp 711–722

Phenylalanine ammonia-lyase gene structure, expression, and evolution in Nicotiana

  • Tomoko Fukasawa-Akada
  • Shain-dow Kung
  • John C. Watson
Research Article

DOI: 10.1007/BF00019006

Cite this article as:
Fukasawa-Akada, T., Kung, S. & Watson, J.C. Plant Mol Biol (1996) 30: 711. doi:10.1007/BF00019006

Abstract

Phenylalanine ammonia-lyase (PAL) catalyzes the first reaction in the general phenylpropanoid pathway leading to the production of phenolic compounds with a significant range of biological functions. A PAL gene we designated gPAL1, cloned from tobacco, consists of two exons separated by an intron of 1932 bp. Exon I, 398 bp, and exon II, 1747 bp, together encode a polypeptide of 715 amino acids. A putative TATA box and polyadenylation signal are found 144 bp upstream of the initiation codon and 193 bp downstream from the stop codon, respectively. Using various parts of gPAL1 as probes, genomic Southern blots indicated the presence of a small family of PAL genes in the tobacco genome that can be divided into two distinct subfamilies, one consisting of pal1 and pal2 and another of pal3 and pal4. Comparative genomic blot analysis of progenitor species (Nicotiana tomentosiformis and N. sylvestris) indicated that each species contains one PAL gene from each of the subfamilies, suggesting that pal1 and pal3 (or pal2 and pal4) diverged prior to the evolution of N. tabacum. Expression of the PAL gene family was examined using RNA gel blots. PAL transcript levels were significantly higher in flowers and roots than in leaves and stems of mature plants. PAL transcripts accumulate differentially during flower and leaf maturation in that mRNA levels decline during flower maturation but increase during leaf maturation. In leaves, PAL transcripts rapidly accumulated after wounding.

Key words

developmental regulationgene expressiongene familyphenylalanine ammonia-lyasetobaccowound response

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Tomoko Fukasawa-Akada
    • 1
    • 2
  • Shain-dow Kung
    • 1
    • 3
  • John C. Watson
    • 4
  1. 1.Department of Plant BiologyUniversity of MarylandCollege ParkUSA
  2. 2.Center for Agricultural BiotechnologyUniversity of MarylandCollege ParkUSA
  3. 3.Department of BiologyHong Kong University of Science and TechnologyKowloonHong Kong
  4. 4.Department of BiologyIndiana University-Purdue University at IndianapolisIndianapolisUSA