The gene promoter for a bean abscission cellulase is ethylene-induced in transgenic tomato and shows high sequence conservation with a soybean abscission cellulase.
Bean leaf abscission (organ separation) correlates with the de novo accumulation of a pI9.5 cellulase and its mRNA. Overlapping genomic clones encoding the bean abscission cellulase (BAC) were isolated and partially sequenced. In addition, a genomic clone for a soybean abscission cellulase (SAC) was identified and the sequence compared to the BAC genomic sequence. Two 5'-upstream regions are particularly well conserved in the two sequences. Of special interest here is the region between -1 and -200 in the BAC promoter which is highly conserved in the SAC gene. Particle gun bombardment with a BAC promoter construct containing 210 bp of BAC sequence 5' to the transcription start site was sufficient to drive abscission-specific and ethylene and auxin-regulated transient expression in bean. In addition to the transient expression assay, expression was examined in stably transformed tomato. A similar -210 bp BAC promoter construct supported a low level of ethylene-inducible reporter gene expression in tomato leaf abscission zones and adjacent petioles but not in ethylene-treated stem tissue or fruit. Expression from the -210 promoter in tomato abscission zones was inhibited by silver thiosulfate, an ethylene action inhibitor, and was partially inhibited by treatment with auxin.
Koehler
S M
SM
Plant Molecular Biology Lab, USDA/ARS, Beltsville, MD 20705, USA.
Matters
G L
GL
Nath
P
P
Kemmerer
E C
EC
Tucker
M L
ML
D001483:Base Sequence; D002480:Cellulase / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D017124:Conserved Sequence; D005030:Ethylenes / Q000494:pharmacology; D007887:Fabaceae / Q000201:enzymology* / Q000235:genetics*; D017930:Genes, Reporter / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology; D008156:Luciferases / Q000096:biosynthesis; D018551:Solanum lycopersicum; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D010946:Plants, Medicinal; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012689:Sequence Homology, Nucleic Acid; D030262:Soybean Proteins; D013025:Glycine max / Q000201:enzymology* / Q000235:genetics*; D013885:Thiosulfates / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
D005030:Ethylenes; D007210:Indoleacetic Acids; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D030262:Soybean Proteins; D013885:Thiosulfates; C095213:silver thiosulfate; C030737:indoleacetic acid; C036216:ethylene; D008156:Luciferases; D002480:Cellulase; C101304:SAC protein, soybean