Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 18, 2000
Publication Date: January 1, 2001
Citation: Lingle, S.E., Dyer, J.M., 2001. Cloning and expression of sucrose synthase-1 cdna from sugarcane. Journal of Plant Physiology. 158:129-131. Interpretive Summary: Isolation of genes that code for important enzymes may help select higher yielding or higher quality sugarcane varieties. One important enzyme in sugarcane, called sucrose synthase, seems to be important in maintaining sucrose movement from leaves to the stem, where it is stored. There are at least two forms of this enzyme. The molecule that tells the cell to make a particular protein is called mRNA. We cloned a copy of the mRNA (called cDNA because it is a DNA molecule that is a copy of the mRNA) for the first sucrose synthase protein in sugarcane. This cDNA is similar in sequence to those for the same protein in maize, rice and barley. The cDNA was used to identify in which organs the mRNA for the protein was being made. We identified the mRNA for sucrose synthase in immature leaves, leaf sheaths, stem apex, internodes, adventitious roots and germinating buds. This research will benefit other scientists doing research on gene expression in sugarcane, and plant breeders who may be able to use this gene as a genetic marker.
Technical Abstract: Sucrose synthase (SuSy, EC 18.104.22.168) is a major enzyme of sucrose metabolism in sugarcane (Saccharum spp. hybrids) internodes. Most plants have at least two differentially expressed, nonallelic SuSy genes. A cDNA of the entire coding sequence of sucrose synthase-1 was isolated from total RNA from an elongating sugarcane internode. Primers designed from published sequences of SuSy-1 from maize (Zea mays), wheat (Triticum aestivum) and rice (Oryza sativa) amplified a 627-bp product through RT- PCR. This was followed by 5'- and 3' rapid amplification of cDNA ends (RACE). The cDNA is 2717 bp long. The nucleotide sequence is similar to that of cDNAs for SuSy-1 from maize (91%), rice (89%) and barley (87%). The putative protein is 802 amino acids long, and 97% identical to the sh1 SuSy protein from maize. An antisense riboprobe of the PCR product detected SuSy-1 transcripts in Northern blots of RNA from immature and mature leaf sheaths, the apex and immature leaf roll, immature and mature internodes, sett roots, and germinating vegetative bud. Expression in mature and immature leaf lamina was slight but detectable. This is the first report of a full-length cDNA of SuSy-1 from sugarcane.