ibclogo XVI International Botanical Congess

Abstract Number: 5753
Poster No. = 2014


IS SUCROSE TRANSPORT LINKED TO EARLY SIGNAL TRANSDUCTION OF SUGAR-MEDIATED GENE EXPRESSION?


R. Gesch, J. Vu, G. Bowes, L. Allen, and K. Boote (U.S. Dept. of Agriculture and University of Florida, Gainesville, FL 32611, USA).


Soluble carbohydrates may modulate the expression of photosynthetic genes. However, rbcS expression in rice (Oryza sativa L.) Does not correlate with carbohydrate pool size. We examined source/sink effects on activated sucrose phosphate synthase (SPS) and acid invertase activity in rice leaves. Plants grown at 350 ppm CO2 were switched for 9 days to either 700 or 175 ppm. One day later SPS activity was up-regulated 28 or down-regulated 27, respectively, but invertase activity was decreased 23 or 43-, respectively. Two days later acid invertase activity had returned to prior levels. Despite higher photosynthetic rates at high CO2, leaf sucrose pool size did not increase. However, TNC (74- sucrose) doubled in the stem and sheath. This change in sucrose export requires new research.

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