Abstract
Acetolactate synthase (ALS), the first enzyme in the biosynthetic pathway of leucine, valine, and isoleucine, is the biochemical target of different herbicides. To investigate the effects of repression of ALS activity through antisense gene expression we cloned an ALS gene from potato (Solanum tuberosum L. cv Desiree), constructed a chimeric antisense gene under control of the cauliflower mosaic virus 35S promoter, and created transgenic potato plants through Agrobacterium tumefaciens-mediated gene transfer. Two regenerants revealed severe growth retardation and strong phenotypical effects resembling those caused by ALS-inhibiting herbicides. Antisense gene expression decreased the steady-state level of ALS mRNA in these plants and induced a corresponding decrease in ALS activity of up to 85%. This reduction was sufficient to generate plants almost inviable without amino acid supplementation. In both ALS antisense and herbicide-treated plants, we could exclude accumulation of 2-oxobutyrate and/or 2-aminobutyrate as the reason for the observed deleterious effects, but we detected elevated levels of free amino acids and imbalances in their relative proportions. Thus, antisense inhibition of ALS generated an in vivo model of herbicide action. Furthermore, expression of antisense RNA to the enzyme of interest provides a general method for validation of potential herbicide targets.
Full Text
The Full Text of this article is available as a PDF (2.6 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chapple C. C., Vogt T., Ellis B. E., Somerville C. R. An Arabidopsis mutant defective in the general phenylpropanoid pathway. Plant Cell. 1992 Nov;4(11):1413–1424. doi: 10.1105/tpc.4.11.1413. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Falco S. C., Dumas K. S., Livak K. J. Nucleotide sequence of the yeast ILV2 gene which encodes acetolactate synthase. Nucleic Acids Res. 1985 Jun 11;13(11):4011–4027. doi: 10.1093/nar/13.11.4011. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Frankard V., Ghislain M., Jacobs M. Two Feedback-Insensitive Enzymes of the Aspartate Pathway in Nicotiana sylvestris. Plant Physiol. 1992 Aug;99(4):1285–1293. doi: 10.1104/pp.99.4.1285. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hattori J., Rutledge R., Labbé H., Brown D., Sunohara G., Miki B. Multiple resistance to sulfonylureas and imidazolinones conferred by an acetohydroxyacid synthase gene with separate mutations for selective resistance. Mol Gen Genet. 1992 Mar;232(2):167–173. doi: 10.1007/BF00279993. [DOI] [PubMed] [Google Scholar]
- Hildmann T., Ebneth M., Peña-Cortés H., Sánchez-Serrano J. J., Willmitzer L., Prat S. General roles of abscisic and jasmonic acids in gene activation as a result of mechanical wounding. Plant Cell. 1992 Sep;4(9):1157–1170. doi: 10.1105/tpc.4.9.1157. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Höfgen R., Axelsen K. B., Kannangara C. G., Schüttke I., Pohlenz H. D., Willmitzer L., Grimm B., von Wettstein D. A visible marker for antisense mRNA expression in plants: inhibition of chlorophyll synthesis with a glutamate-1-semialdehyde aminotransferase antisense gene. Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1726–1730. doi: 10.1073/pnas.91.5.1726. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jackson S. D., Sonnewald U., Willmitzer L. Cloning and expression analysis of beta-isopropylmalate dehydrogenase from potato. Mol Gen Genet. 1993 Jan;236(2-3):309–314. doi: 10.1007/BF00277127. [DOI] [PubMed] [Google Scholar]
- Kishore G. M., Shah D. M. Amino acid biosynthesis inhibitors as herbicides. Annu Rev Biochem. 1988;57:627–663. doi: 10.1146/annurev.bi.57.070188.003211. [DOI] [PubMed] [Google Scholar]
- LaRossa R. A., Van Dyk T. K., Smulski D. R. Toxic accumulation of alpha-ketobutyrate caused by inhibition of the branched-chain amino acid biosynthetic enzyme acetolactate synthase in Salmonella typhimurium. J Bacteriol. 1987 Apr;169(4):1372–1378. doi: 10.1128/jb.169.4.1372-1378.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lawther R. P., Calhoun D. H., Adams C. W., Hauser C. A., Gray J., Hatfield G. W. Molecular basis of valine resistance in Escherichia coli K-12. Proc Natl Acad Sci U S A. 1981 Feb;78(2):922–925. doi: 10.1073/pnas.78.2.922. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee K. Y., Townsend J., Tepperman J., Black M., Chui C. F., Mazur B., Dunsmuir P., Bedbrook J. The molecular basis of sulfonylurea herbicide resistance in tobacco. EMBO J. 1988 May;7(5):1241–1248. doi: 10.1002/j.1460-2075.1988.tb02937.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McGrath R. B., Coruzzi G. M. A gene network controlling glutamine and asparagine biosynthesis in plants. Plant J. 1991 Nov;1(3):275–280. doi: 10.1046/j.1365-313x.1991.00999.x. [DOI] [PubMed] [Google Scholar]
- Miflin B. J. Cooperative feedback control of barley acetohydroxyacid synthetase by leucine, isoleucine, and valine. Arch Biochem Biophys. 1971 Oct;146(2):542–550. doi: 10.1016/0003-9861(71)90159-7. [DOI] [PubMed] [Google Scholar]
- Ray T. B. Site of action of chlorsulfuron: inhibition of valine and isoleucine biosynthesis in plants. Plant Physiol. 1984 Jul;75(3):827–831. doi: 10.1104/pp.75.3.827. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rocha-Sosa M., Sonnewald U., Frommer W., Stratmann M., Schell J., Willmitzer L. Both developmental and metabolic signals activate the promoter of a class I patatin gene. EMBO J. 1989 Jan;8(1):23–29. doi: 10.1002/j.1460-2075.1989.tb03344.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rodermel S. R., Abbott M. S., Bogorad L. Nuclear-organelle interactions: nuclear antisense gene inhibits ribulose bisphosphate carboxylase enzyme levels in transformed tobacco plants. Cell. 1988 Nov 18;55(4):673–681. doi: 10.1016/0092-8674(88)90226-7. [DOI] [PubMed] [Google Scholar]
- Shaner D. L., Singh B. K. Phytotoxicity of Acetohydroxyacid Synthase Inhibitors Is Not Due to Accumulation of 2-Ketobutyrate and/or 2-Aminobutyrate. Plant Physiol. 1993 Dec;103(4):1221–1226. doi: 10.1104/pp.103.4.1221. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Singh B., Schmitt G., Lillis M., Hand J. M., Misra R. Overexpression of Acetohydroxyacid Synthase from Arabidopsis as an Inducible Fusion Protein in Escherichia coli: Production of Polyclonal Antibodies, and Immunological Characterization of the Enzyme. Plant Physiol. 1991 Oct;97(2):657–662. doi: 10.1104/pp.97.2.657. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith J. K., Schloss J. V., Mazur B. J. Functional expression of plant acetolactate synthase genes in Escherichia coli. Proc Natl Acad Sci U S A. 1989 Jun;86(11):4179–4183. doi: 10.1073/pnas.86.11.4179. [DOI] [PMC free article] [PubMed] [Google Scholar]