Abstract
In the cotyledons of mustard (Sinapis alba L.) seedlings irradiated from the time of sowing with continuous red light, the photoreversibility of the phytochrome-mediated increase in β-amylase activity (EC 3.2.1.2) is lost 36 h after sowing (coupling point). However, the induced increase of β-amylase activity cannot be detected before 46 h after sowing (starting point). Density labeling with deuterium oxide shows that the increase of enzyme activity in light and darkness coincides precisely with the synthesis of β-amylase protein. Thus, phytochrome mediates an increase of β-amylase synthesis de novo. Since there is no turnover detectable by density labeling, it is concluded that β-amylase of mustard cotyledons is a physiologically stable enzyme (half-life >5 d). The 10-h time gap between loss of photoreversibility and onset of light-induced β-amylase synthesis points to a relatively stable regulatory element within the signal chain (“transmitter”) which links β-amylase synthesis to the primary action of phytochrome. A 12-h lag between the cessation of phytochrome action and the cessation of induced β-amylase synthesis indicates a limited lifetime of the transmitter (about 12 h). The effect of this result on the interpretation of the coupling point is discussed.
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Abbreviations
- Pr, Pfr :
-
red and far-red absorbing forms of phytochrome
References
Acton, G.J., Drumm, H., Mohr, H. (1974) Control of synthesis de novo of ascorbate oxidase in the mustard seedling (Sinapis alba L.) by phytochrome. Planta 121, 39–50
Acton, G.J., Fischer, W., Schopfer, P. (1980) Lag-phase and rate of synthesis in phytochrome-mediated induction of phenylalanine ammonia-lyase in mustard (Sinapis alba L.) cotyledons. Planta 150, 53–57
Bernfeld, P. (1955) Amylases, α and β. Methods Enzymol. 1, 149–150
boudet, A., Humphrey, T.J., Davies, D.D. (1975) The measurement of protein turnover by density labelling. Biochem. J. 152, 409–416
Cooke, R.J., Grego, S., Oliver, J., Davies, D.D. (1979) The effect of deuterium oxide on protein turnover in Lemna minor. Planta 146, 229–236
Cooke, R.J., Grego, S., Roberts, K., Davies, D.D. (1980) The mechanism of deuterium oxide-induced protein degradation in Lemna minor. Planta 148, 374–480
Daussant, J., Corvazier, P. (1970) Biosynthesis and modifications of and β-amylase in germinating wheat seeds. FEBS Lett. 7, 191–194
Drumm, H., Elchinger, L., Möller, J., Peter, K., Mohr, H. (1971) Induction of amylase in mustard seedlings by phytochrome. Planta 99, 265–274
Frosch, S., Drumm, H., Mohr, H. (1977) Regulation of enzyme levels by phytochrome in mustard cotyledons: multiple mechanisms? Planta 136, 181–186
Fourcroy, P. (1978) Advantages pf potassium bromide gradients for isopycnic centrifugation of proteins. Biochem. Biophys. Res. Commun. 84, 713–720
Hillman, W.S. (1972) On the physiological significance of in vivo phytochrome assays. In: Phytochrome, pp. 573–584. Mitrakos, K., Shropshire, W. (eds.) Academic Press, New York
Hong, Y.-N., Schopfer, P. (1981) Control by phytochrome of urate oxidase and allantoinase activities during peroxisome development in the cotyledons of mustard (Sinapis alba L.) seedlings. Planta 152, 325–335
Humphrey, T.J., Davies, D.D. (1975) A new method for the measurement of protein turnover. Biochem. J. 148, 119–127
Jacobsen, J.V., Scandalios, J.G., Varner, J.E. (1970) Multiple forms of amylase induced by gibberellic acid in isolated barley aleurone layers. Plant Physiol. 45, 367–371
Johnson, C.B., Smith, H. (1978) Phytochrome control of amino acid synthesis in cotyledons of Sinapis alba. Phytochemistry 17, 667–670
Mohr, H. (1978) Pattern specification and realization in photomorphogenesis. Bot. Mag. Tokyo Special Issue 1, 199–217
Rickwood, D., ed. (1978) Centrifugation: a practical approach. Information Retrieval Limited, London Washington D.C.
Schäfer, E., Schmidt, W., Mohr, H. (1973) Comparative measurements of phytochrome in cotyledons and hypocotyl hook of mustard (Sinapis alba L.). Photochem. Photobiol. 18, 331–334
Schopfer, P. (1977) Phytochrome control of enzymes. Annu. Rev. Plant Physiol. 28, 223–252
Schopfer, P., Plachy, C. (1973) Die organspezifische Photodetermination der Entwicklung von Peroxydaseaktivität im Senfkeimling (Sinapis alba L.) durch Phytochrom. I. Kinetische Analyse. Z. Naturforsch. 28c, 296–301
Steinitz, B., Drumm, H., Mohr, H. (1976) The appearance of competence for phytochrome-mediated anthocyanin synthesis in the cotyledons of Sinapis alba L. Planta 130, 23–31
Tong, W.-F., Schopfer, P. (1976) Phytochrome-mediated de novo synthesis of phenylalanine ammonia-lyase: an approach using pre-induced mustard seedlings. Proc. Natl. Acad. Sci. USA 73, 4017–4021
Tong, W.-F., Schopfer, P. (1978) Absence of Pfr destruction in the modulation of phenylalanine ammonia-lyase synthesis of mustard cotyledons. Plant Physiol. 61, 59–61
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Sharma, R., Schopfer, P. Sequential control of phytochrome-mediated synthesis de novo of β-amylase in the cotyledons of mustard (Sinapis alba L.) seedlings. Planta 155, 183–189 (1982). https://doi.org/10.1007/BF00392550
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DOI: https://doi.org/10.1007/BF00392550