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ARS Home » Research » Publications at this Location » Publication #117348
Title: WOUND INDUCTION OF A TOMATO GENE ENCODING A PROTEIN SIMILAR TO A CYTOCHROME P450 ENZYME

Author
item BARTOSZEWSKI, GREG - WARSAW AGRI UNIV POLAND
item MUJER, CESAR - USDA ARS BA PSI MPPL
item NIEMIROWICZ-S, KATARZYNA - WARSAW AGRIC UNIV POLAND
item Smigocki, Anna

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Insect pests cause devastating yield losses to farmers around the world. In this investigation, the mechanism of insect resistance in genetically engineered plants that carry a gene involved in the production of a plant growth hormone cytokinin was analyzed. To understand how the hormone increases the level of insect resistance, we isolated a gene that codes for an enzyme that is likely involved in the synthesis of compounds with insecticidal activity. The expression of this gene was found to be enhanced by high cytokinin levels, wounding or by feeding insects. In the present study, this gene was cloned from tomato to evaluate the similarity of these genes in different plants. The tomato gene was found to be induced by wounding but not by applications of the growth hormone cytokinin. Agricultural biotechnology companies could potentially tap this gene for generating transgenic plants that could synthesize higher amounts of the insecticidal compounds. This study will also provide valuable information for other scientists to further manipulate the biosynthetic pathways that produce compounds for insect resistance and lead to environmentally safer approaches for reducing the pollution created by pesticide applications.

Technical Abstract: A Lycopersicon esculentum cv Rutgers cDNA clone with high similarity to a Nicotiana plumbaginifolia putative cytochrome P450 monooxygenase was isolated using 5' and 3' RACE. The isolated cDNA (GenBank Accession No. AF249329) has an open reading frame of 1494 bp and encodes a protein 498 amino acids. The deduced protein sequence has 75% identity to the N. plumbaginifolia P450 (CYP72A2) and 41% to the Catharanthus roseus CYP72A1. The genomic P450 sequence obtained by PCR was shown to contain three short introns. Southern-blot analysis revealed 2 highly homologous genes in the tomato genome. Expression of the P450 clone in mature leaves is regulated by circadian rhythm and enhanced by wounding. Leaf transcript levels were highest 3 hr after mechanical wounding. Expression of cloned gene is tissue specific with highest levels of expression in the shoot tips and in young leaves and fruits. Zeatin application and uptake experiments did not increase the expression of the tomato P450 gene. The function of this gene is presently not known.