Abstract
The sos1 mutant of Arabidopsis thaliana is more than 20 times more sensitive to NaCl stress than wild type Arabidopsis. Because proline (Pro) is generally thought to have an important role in plant salt tolerance, the sos1 mutant and the wild type were compared with respect to their capacity to accumulate Pro under NaCl stress, and sos1 mutant plants accumulated more Pro than wild-type. The P5CS gene, which catalyzes the rate-limiting step in Pro biosynthesis, is induced by salt stress to a higher level in sos1 than in the wild type. Although a defective high-affinity K uptake system in sos1 causes K deficiency and inhibits growth in NaCl-treated plants, this decrease is not a sufficient signal for Pro accumulation and P5CS gene expression. Not all salt-stress-induced genes have a higher level of expression in sos1. The expression levels of AtPLC and RD29A, which encode a phospholipase C homolog and a putative protective protein, respectively, are the same in sos1 as in the wild type. However, the expression of AtMYB, which encodes a putative transcriptional factor, is induced to a much higher level by salt stress in sos1. Thus, the SOS1 gene product serves as a negative regulator for the expression of P5CS and AtMYB, but has no effect on AtPLC and RD29A expression.
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- Adams E., Frank L. Metabolism of proline and the hydroxyprolines. Annu Rev Biochem. 1980;49:1005–1061. doi: 10.1146/annurev.bi.49.070180.005041. [DOI] [PubMed] [Google Scholar]
- Boyer J. S. Plant productivity and environment. Science. 1982 Oct 29;218(4571):443–448. doi: 10.1126/science.218.4571.443. [DOI] [PubMed] [Google Scholar]
- Bray E. A. Molecular Responses to Water Deficit. Plant Physiol. 1993 Dec;103(4):1035–1040. doi: 10.1104/pp.103.4.1035. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Csonka L. N., Hanson A. D. Prokaryotic osmoregulation: genetics and physiology. Annu Rev Microbiol. 1991;45:569–606. doi: 10.1146/annurev.mi.45.100191.003033. [DOI] [PubMed] [Google Scholar]
- Delauney A. J., Verma D. P. A soybean gene encoding delta 1-pyrroline-5-carboxylate reductase was isolated by functional complementation in Escherichia coli and is found to be osmoregulated. Mol Gen Genet. 1990 May;221(3):299–305. doi: 10.1007/BF00259392. [DOI] [PubMed] [Google Scholar]
- Ding L., Zhu J. K. Reduced Na+ uptake in the NaCl-hypersensitive sos1 mutant of Arabidopsis thaliana. Plant Physiol. 1997 Mar;113(3):795–799. doi: 10.1104/pp.113.3.795. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hirayama T., Ohto C., Mizoguchi T., Shinozaki K. A gene encoding a phosphatidylinositol-specific phospholipase C is induced by dehydration and salt stress in Arabidopsis thaliana. Proc Natl Acad Sci U S A. 1995 Apr 25;92(9):3903–3907. doi: 10.1073/pnas.92.9.3903. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hu C. A., Delauney A. J., Verma D. P. A bifunctional enzyme (delta 1-pyrroline-5-carboxylate synthetase) catalyzes the first two steps in proline biosynthesis in plants. Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):9354–9358. doi: 10.1073/pnas.89.19.9354. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ishitani M., Majumder A. L., Bornhouser A., Michalowski C. B., Jensen R. G., Bohnert H. J. Coordinate transcriptional induction of myo-inositol metabolism during environmental stress. Plant J. 1996 Apr;9(4):537–548. doi: 10.1046/j.1365-313x.1996.09040537.x. [DOI] [PubMed] [Google Scholar]
- Kishor PBK., Hong Z., Miao G. H., Hu CAA., Verma DPS. Overexpression of [delta]-Pyrroline-5-Carboxylate Synthetase Increases Proline Production and Confers Osmotolerance in Transgenic Plants. Plant Physiol. 1995 Aug;108(4):1387–1394. doi: 10.1104/pp.108.4.1387. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koornneef M., Dellaert L. W., van der Veen J. H. EMS- and radiation-induced mutation frequencies at individual loci in Arabidopsis thaliana (L.) Heynh. Mutat Res. 1982 Mar;93(1):109–123. doi: 10.1016/0027-5107(82)90129-4. [DOI] [PubMed] [Google Scholar]
- Moftah A. E., Michel B. E. The effect of sodium chloride on solute potential and proline accumulation in soybean leaves. Plant Physiol. 1987 Feb;83(2):238–240. doi: 10.1104/pp.83.2.238. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sutherland L., Cairney J., Elmore M. J., Booth I. R., Higgins C. F. Osmotic regulation of transcription: induction of the proU betaine transport gene is dependent on accumulation of intracellular potassium. J Bacteriol. 1986 Nov;168(2):805–814. doi: 10.1128/jb.168.2.805-814.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Urao T., Yamaguchi-Shinozaki K., Urao S., Shinozaki K. An Arabidopsis myb homolog is induced by dehydration stress and its gene product binds to the conserved MYB recognition sequence. Plant Cell. 1993 Nov;5(11):1529–1539. doi: 10.1105/tpc.5.11.1529. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wu S. J., Ding L., Zhu J. K. SOS1, a Genetic Locus Essential for Salt Tolerance and Potassium Acquisition. Plant Cell. 1996 Apr;8(4):617–627. doi: 10.1105/tpc.8.4.617. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yamaguchi-Shinozaki K., Shinozaki K. Characterization of the expression of a desiccation-responsive rd29 gene of Arabidopsis thaliana and analysis of its promoter in transgenic plants. Mol Gen Genet. 1993 Jan;236(2-3):331–340. doi: 10.1007/BF00277130. [DOI] [PubMed] [Google Scholar]
- Yoshiba Y., Kiyosue T., Katagiri T., Ueda H., Mizoguchi T., Yamaguchi-Shinozaki K., Wada K., Harada Y., Shinozaki K. Correlation between the induction of a gene for delta 1-pyrroline-5-carboxylate synthetase and the accumulation of proline in Arabidopsis thaliana under osmotic stress. Plant J. 1995 May;7(5):751–760. doi: 10.1046/j.1365-313x.1995.07050751.x. [DOI] [PubMed] [Google Scholar]
- Zhang C. S., Lu Q., Verma D. P. Removal of feedback inhibition of delta 1-pyrroline-5-carboxylate synthetase, a bifunctional enzyme catalyzing the first two steps of proline biosynthesis in plants. J Biol Chem. 1995 Sep 1;270(35):20491–20496. doi: 10.1074/jbc.270.35.20491. [DOI] [PubMed] [Google Scholar]