Proline alleviates salt-stress-induced enhancement in ribulose-1, 5-bisphosphate oxygenase activity.
Sodium chloride enhanced oxygenase activity while curtailing carboxylase activity of Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39) purified to electrophoretic homogeneity. Exposure to 200 mM NaCl brought about an increase in the potential of Rubisco to oxygenate RuBP by over 50%. On the other hand, proline suppressed both oxygenase as well as carboxylase activities of Rubisco. Interestingly, proline-induced suppression in oxygenase activity was significantly higher than that of carboxylase activity. Most amazingly, salt-stress-induced enhancement in oxygenase activity was fully alleviated by proline even when present at a concentration as low as 50 mM. The findings presented in this communication clearly demonstrate for the first time that stress-induced proline accumulation might have a critical role in lowering the loss in fixed carbon by curtailing salt-stress-promoted enhancement in oxygenase activity of Rubisco.
Sivakumar
P
P
Plant Physiology and Biotechnology Laboratory, Jamia Millia Islamia, New Delhi, 110025, India.
Sharmila
P
P
Pardha Saradhi
P
P
D007887:Fabaceae / Q000201:enzymology / Q000502:physiology*; D007700:Kinetics; D009994:Osmolar Concentration; D010946:Plants, Medicinal; D011392:Proline / Q000494:pharmacology*; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*; D012274:Ribulosephosphates / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology
D012274:Ribulosephosphates; C001933:ribulose-1,5 diphosphate; D012965:Sodium Chloride; D011392:Proline; D012273:Ribulose-Bisphosphate Carboxylase