Plant Molecular Biology

, Volume 21, Issue 6, pp 1035–1051

Organisation of the tomato polyphenol oxidase gene family

  • Sally M. Newman
  • Nancy T. Eannetta
  • Haifeng Yu
  • James P. Prince
  • M. Carmen de Vicente
  • Steven D. Tanksley
  • John C. Steffens
Research Articles

DOI: 10.1007/BF00023601

Cite this article as:
Newman, S.M., Eannetta, N.T., Yu, H. et al. Plant Mol Biol (1993) 21: 1035. doi:10.1007/BF00023601

Abstract

We report the isolation and characterization of seven nuclear genes encoding polyphenol oxidase (PPO) in tomato (Lycopersicon esculentum cv. VFNT Cherry). The seven genes (PPOs A, A′, B, C, D, E and F) fall into three structural classes (I, II, and III) based on Eco RI and Hind III restriction fragment length polymorphisms (RFLP). RFLP mapping and PFGE analysis demonstrated that the genes reside on chromosome 8, and may be clustered within a 165 kb region. Phage insert mapping demonstrated PPO E and PPO F (both class III), and PPOs B, D and A (classes I, II and I respectively) are grouped within separate 12.4 kb clusters. The complete nucleotide sequence was determined for each gene. Comparison to cDNAs revealed that the PPOs lack introns. A transcript of about 2 kb is expected for each PPO. Each PPO possesses a region encoding a transit peptide characteristic of polypeptides targeted to the thylakoid lumen. Predicted precursor polypeptides range in mass from 66 to 71 kDa and predicted mature polypeptides range from 57 to 62 kDa. All the PPOs encode two putative copper-binding sites characteristic of bacterial, fungal and mammalian tyrosinases. Five of the seven PPOs possess divergent DNA sequences in their 5′ promoter regions. These flanking sequence differences may regulate the differential expression of PPO genes.

Key words

epidermis gene family plastids polyphenol oxidase tomato tyrosinase 

Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • Sally M. Newman
    • 1
  • Nancy T. Eannetta
    • 1
  • Haifeng Yu
    • 1
  • James P. Prince
    • 1
  • M. Carmen de Vicente
    • 1
  • Steven D. Tanksley
    • 1
  • John C. Steffens
    • 1
  1. 1.Department of Plant Breeding and BiometryCornell UniversityIthacaUSA

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