Sucrose Transporter Genes and Their Functions in Plants

In plants, sucrose is the major or even sole carbon source for long-distance transport and is both a source of carbon skeletons and energy for plant growth and development. Sucrose transmembrane events occur by means of a kind of carrier protein (i.e., sucrose transporter SUT), which then plays a critical role in phloem-mediated source-to-sink Sucrose transport and Sucrose uptake to sinks. Since the first identification and cloning of a SUT cDNA from spinach, many SUT cDNAs have been cloned and characterized in 34 different plant species, in both dicots and monocots. In each plant species, SUTs represent a medium-sized gene family, containing members with high amino acid identity but differences in kinetic properties, substrate specificity and expression patterns. In this paper, we review the advances in the past decade concerning different aspects of SUT genes, including classification and phylogeny, cellular localization and function, and research methods employed. Our preliminary results in the SUT genes of Hevea brasiliensis are also presented.