ISOLATION AND EXPRESSION OF SUCROSE SYNTHASE-1 cDNA IN SUGARCANE

USDA-ARS-SRRC, P.O. Box 19687, New Orleans, LA 70179

Sucrose synthase (SS, EC 2.4.1.13) is a major enzyme of sucrose metabolism in sugarcane (Saccharum spp. hybrids) internodes. In most plants there are at least two differentially expressed sucrose synthase genes. A partial cDNA for sucrose synthase-1 was isolated from an elongating sugarcane internode by RT-PCR using primers designed from published sequences of SS-1 from maize, wheat and rice. The 627 base-pair sequence was about 90% homologous to SS-1 cDNAs from maize, wheat and rice. The translated polypeptide from this fragment was 98% identical to the maize Sh1 protein. Full-length cDNA was then obtained by 5'- and 3'-RACE. The expression of SS-1 in immature and mature leaves, and developing internodes, determined by Northern analysis, will be presented.