Proline metabolism and NAD kinase activity in soybean calli during short- and long-term exposures to light and NaCl
1998
Guerrier, G. (Universite d'Orleans (France)) | Delumeau, O. | Renard, M. | Laval-Martin, D.
Calli of soybean (Glycine max) cv. Maple Arrow grew better and accumulated more proline when cultured for 5 d on 70 mM NaCl under darkness than at light. This rapid proline accumulation in salinized soybean calli appeared to play a protective role rather than to be a cause of growth failure. Throughout a 28 d-culture cycle, we followed the possible relationships between the proline contents and the activities of enzymes of proline biosynthesis [ornithine transaminase; NAD(P)H-pyrroline-5-carboxylate reductase], of proline catabolism [NAD(P) proline dehydrogenase], and of NAD kinase responsible of variations in NADP(H) contents. Enzyme activities of proline metabolism and NAD kinase were clearly light- and NaCl-regulated; nevertheless, relationships between enzyme activities and proline content existed only in calli grown for short-term under darkness and in presence of NaCl. The ornithine transaminase route, which was particularly enhanced in these calli during the first days of salt application, seemed to be involved in the initial proline accumulation in soybean.
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