CLONING AND EXPRESSION ANALYSIS OF A GENE THAT SHOWS DEVELOPMENTAL REGULATION UPON TUBERIZATION IN POTATO

Differential screening of a potato leaf cDNA library with cDNA probes made from tuberizing and non-tuberizing Solanum demissum plants led to the identification of a clone that is upregulated in leaves and other tissues upon tuberization. This clone was also shown to have a high l evel of expression in green tomato fruit, its expression falling off a s the fruit turns red. No sucrose or hormonal regulation of the expres sion of this clone was observed and it did not respond to wounding or heat stress. Clone 32B is 532 bp long and contains an open reading fra me encoding a small protein of 98 amino acids. The deduced protein seq uence has a putative signal peptide for ER transport and a 10 amino ac id domain in the C-terminal region of the protein, both or which are a lso found in the cotton LEAS, Arabidopsis Di21 and the mungbean Arg2 p roteins.