W. Odegard et al., CLONING AND EXPRESSION OF RICE (ORYZA-SATIVA) SUCROSE SYNTHASE-1 (RSS1) IN DEVELOPING SEED ENDOSPERM, PLANT SCI, 113(1), 1996, pp. 67-78
A previously cloned cDNA to rice (Oryza sativa L.) sucrose synthase 1
(RSs1) was used to determine spatial expression of the gene in rice ti
ssues and temporal expression in developing rice endosperm. RSs1 was e
xpressed predominantly in the endosperm of milky stage rice seeds with
maximum expression at 3-5 days after pollination which were 8-10-fold
over leaf levels. The peak in RSs1 transcript levels preceded the pea
k of enzyme activity which occured 9-11 days after pollination. RSs1 t
ranscript and activity levels were analyzed in two starch deficient mu
tants of rice to determine if the lesion in these mutants resides at t
he locus for RSs1. No correlation between sucrose synthase activity an
d starch biosynthesis was seen in these mutants, although slight eleva
tions of RSs1 transcript levels were observed.