Circadian and senescence-enhanced expression of a tobacco cysteine protease gene
A cDNA clone encoding a cysteine protease was isolated from a tobacco cDNA library, utilizing as a probe a PCR fragment obtained from degenerated primers based on the conserved sequences of plant cysteine protease genes. A putative protein encoded by the clone NTCP-23 had an amino acid sequence with significant similarities to those of plant senescence-associated cysteine proteases and mammalian cathepsin H. Northern blot analysis showed that NTCP-23 mRNA is expressed in all organs and the mRNA and protein expression is enhanced during natural senescence. We propose that NTCP-23 is responsible for amino acid remobilization especially in senescencing leaves. Furthermore, it was found that the mRNA expression follows a circadian rhythm and is reduced by continuous darkness, wounding and hypersensitive reaction (HR). NTCP-23 is the first cysteine protease whose mRNA expression has been shown to be temporarily reduced by wounding.
Unable to display preview. Download preview PDF.
- Arnon, D.I. 1949. Copper enzymes in isolated chloroplasts. Polyphenol oxidases in Beta vulgaris. Plant Physiol. 24: 1–15.Google Scholar
- Biswal, U.C., Biswal, B. 1984 Photocontrol of leaf senescence. Photochem. Photobiol. 39: 875–879.Google Scholar
- Forsthoefel, N.R., Cushman, M.A.F., Ostrem, J.A. and Cushman, J.C. 1998. Induction of a cysteine protease cDNA from Mesembryanthemum crystallinum leaves by environmental stress and plant growth regulators. Plant Sci. 136: 195–206.Google Scholar
- Holwerda, B.C. and Rogers, J.C. 1993. Structure, functional properties and vacuolar targeting of the barley thiol protease, aleurain. J. Exp. Bot. 44: 321–329.Google Scholar
- Koizumi, M., Yamaguchi-Shinozaki, K., Tsuji, H., and Shinozaki, K. 1993. Structure and expression of two genes that encode 657 distinct drought-inducible cysteine proteinases in Arabidopsis thaliana. Gene 129: 175–182.Google Scholar
- Lohman, K.N., Gan, S., John, M.C. and Amasino, R.M. 1994. Molecular analysis of natural leaf senescence in Arabidopsis thaliana. Physiol Plant. 92: 322–328.Google Scholar
- Morris, K., Thomas, H. and Rogers, L. 1996. Endopeptidases during the development and senescence of Lolium temulentum leaves. Phytochemistry 4: 377–384.Google Scholar
- Ohtsubo, N., Mitsuhara, I., Koga, M., Seo, S. and Ohashi Y. 1999. Ethylene promotes the necrotic lesion formation and basic PR gene expression in TMV-infected tobacco. Plant Cell Physiol 40: 808–817.Google Scholar
- Schaffer, M.A. and Fischer, R.L. 1988. Analysis of mRNAs that accumulate in response to low temperature identifies a thiol protease gene in tomato. Plant Physiol. 87: 431–436.Google Scholar
- Wittenbach, V.A. 1977. Induced senescence of intact wheat seedlings and its reversibility. Plant Physiol. 59: 1039–1042.Google Scholar
- Wittenbach, V.A. 1978. Breakdown of ribulose bisphophate carboxylase and change in proteolytic activity during dark-induced senescence of wheat seedlings. Plant Physiol. 62: 604–608.Google Scholar