Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/1998
Publication Date: N/A
Interpretive Summary: Abscission (organ separation) reduces the yield of agriculturally important crops. Our goal is to genetically engineer plants with economically beneficial abscission characteristics. Cellulases and polygalacturonase (PG) are enzymes that are important in breaking down the cell wall surrounding plant cells allowing the cells to separate from each other. We have cloned a cellulase mRNA and gene, cel5, (plant genetic material) from tomato. In addition we examined the expression of this gene in several tissues to determine if the same genetic material is used in each of these tissues. The cel5 gene is, in order of abundance, expressed in pistils of fully open flowers, flower pedicel abscission zones, leaf abscission zones and ripening fruit. The purpose of this study is to define and characterize genetic material that scientists and biotechnologists can use to genetically engineer plants with beneficial abscission properties (i.e., increased yield and quality).
Technical Abstract: A cDNA (TAC1) and corresponding genomic clone (cel5) encoding an endo-beta-1,4-glucanase (cellulase) were identified from tomato (Lycopersicon esculentum Mill., cv. Rutgers). RNA blot analysis indicates that TAC1 is, in order of abundance, expressed in pistils (ovaries removed) of fully open flowers, flower pedicel and leaf abscission zones, and ripening fruit. Translation of the open reading frame in TAC1 produces a 497 a.a. peptide that has 92% sequence identity with a pepper cellulase (ccel2) and 98.8% identity with the 168 a.a. translation product of a tomato PCR clone (cel5). The genomic sequence includes a putative TATA box 30 nucleotides upstream from the start of the TAC1 cDNA.