Sugar accumulation in grape berries. Cloning of two putative vacuolar invertase cDNAs and their expression in grapevine tissues.

AUTOR(ES)

Davies, C

RESUMO

During grape berry (Vitis vinifera L.) ripening, sucrose transported from the leaves is accumulated in the berry vacuoles as glucose and fructose. To study the involvement of invertase in grape berry ripening, we have cloned two cDNAs (GIN1 and GIN2) from berries. The cDNAs encode translation products that are 62% identical to each other and both appear to be vacuolar forms of invertase. Both genes are expressed in a variety of tissues, including berries, leaves, roots, seeds, and flowers, but the two genes have distinct patterns of expression. In grape berries, hexose accumulation began 8 weeks postflowering and continued until the fruit was ripe at 16 weeks. Invertase activity increased from flowering, was maximal 8 weeks postflowering, and remained constant on a per berry basis throughout ripening. Expression of GIN1 and GIN2 in berries, which was high early in berry development, declined greatly at the commencement of hexose accumulation. The results suggest that although vacuolar invertases are involved in hexose accumulation in grape berries, the expression of the genes and the synthesis of the enzymes precedes the onset of hexose accumulation by some weeks, so other mechanisms must be involved in regulating this process.

Documentos Relacionados

• Cloning of a full-length cDNA for malic enzyme (EC 1.1.1.40) from grape berries.
• Cloning and sequencing of cDNAs encoding the two subunits of Crotoxin.
• Cloning, expression, and characterization of cDNAs encoding Arabidopsis thaliana squalene synthase.
• Cloning and characterization of cDNAs encoding equine infectious anemia virus tat and putative Rev proteins.
• Cloning and characterization of two cDNAs coding for human von Willebrand factor.