TREHALOSE AFFECTS SUCROSE SYNTHASE AND INVERTASE ACTIVITIES IN SOYBEAN (GLYCINE-MAX [L.] MERR.) ROOTS

Soybean nodules are known to contain high or low levels of trehalose, depending on the Bradyrhizobium strain that colonizes them. We examine d whether trehalose can affect sucrose metabolism. Experiments with so ybean plantlets grown under sterile conditions demonstrated that treha lose, added to the growth medium, strongly induced sucrose synthase an d, to a lesser extent, alkaline invertase. A comparative study showed that nodules with high levels of trehalose had significantly higher le vels of sucrose synthase and alkaline invertase, and significantly low er levels of sucrose than nodules with low levels of trehalose. Thus, trehalose produced by symbiotic microorganisms may have a regulatory r ole in sucrose metabolism in plants.