ARS | Publication request: Sucrose Synthase, Udp-Glucose Pyrophosphorylase, Starch Synthase, and Starch Debranching Enzyme Activity in Selected Rice Cultivars

Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: June 25, 2005
Publication Date: September 11, 2005
Citation: Bryant, R.J., Counce, P. 2005. Sucrose synthase, udp-glucose pyrophosphorylase, starch synthase, and starch debranching enzyme activity in selected rice cultivars. American Association of Cereal Chemists Meetings, September 11-14, 2005, Orlando, FL. 0-35. pp. 74.

Technical Abstract: Year to year and location to location variation in rice grain quality has been frequently attributed to the environment, genetics and their interaction. As an ongoing project to better understand the biochemical cause of the variations, five U.S. long grain (USLG) cultivars, two lines derived from indica/japonica crosses (I/J) and four Chinese indica (I) lines were grown in field plots near Stuttgart, AR in 2004. Plots were arranged in a randomized complete block design experiment with four replications. The activities of sucrose synthase, UDP-glucose pyrophosphorylase (UGP), starch synthase, and starch debranching enzymes are critical to the formation of starch in the rice endosperm, and thus grain quality. These enzymes were determined at the R6 growth stage (grain filling). The I lines, except for the smaller seeded Qiguizao, had higher sucrose synthase activity than the USGL which were higher than I/J line and Qiguizao. UGP and sucrose synthase activities were not neatly sorted among the three groups. The USLG, Wells, had the highest UGP activity and the two IJ lines the lowest. The USLG, Lemont, had the highest starch synthase and ZHE733 had the lowest. Two different microsatellites of starch synthase were identified and the microsatellite in Lemont and ZHE733 were different. Starch debranching enzyme activity fell into three groups. The IJ lines, Lemont and three of the I lines fell into the middle group while Guichao was in the low activity group.