Sugar sensing in Spirodela punctata

Abstract

The angiosperm Spirodela punctata (Lemnaceae) can utilize glucose and adapt to galactose as the sole carbon source for heterotrophic growth. Two partial cDNAs were isolated from S. punctata by RT-PCR using degenerate primers. SpGAL1 is a 312bp fragment that encodes galactokinase (E.C. 2.7.1.6), and SpHXK a 612bp fragment that encodes hexokinase (E.C. 2.7.1.1). QPCR expression studies showed that SpHXK mRNA transcriptional gene expression levels are always upregulated regardless of the carbon source or the time of sampling. We were unable to test for changes in SpGAL mRNA expression levels.