Differential gene expression during berry ripening in Vitis vinifera (cv Chardonnay) : isolation of specific sequences through subtractive cloning

[摘要] ENGLISH ABSTRACT: Grapevine is worldwide an agronomically important crop. Traditionally selectivebreeding has been used to improve existing cultivars. In the last ten years, however,the advent of biotechnology has shortened these breeding programmes by producingtransgenic grapevine. Because this new technology is aimed at the possible geneticmanipulation of the ripening process in grape berries, it is important to elucidate allthe mechanisms that may be involved in ripening. The aim of the present study wasthe identification of genes that play an important role during the ripening process ingrape berries. This was achieved by investigation of putative differentially expressedgenes in ripening Chardonnay berries isolated through subtractive hybridisation. Twosubtraction libraries, representing early and late ripening stages were constructed.Four of the ten genes analysed exhibited expression during berry ripening. One of thefour genes was expressed in a tissue and stage specific manner. Furthercharacterisation of eight of the DNA and protein sequences revealed that the putativetranslation products of these clones had homologues that are involved in amongstothers cell wall structure in other species. These included UDP-glucosedehydrogenase, which is involved in the synthesis of hemicellulose precursors. Theremaining seven clones encoded putative stress response proteins. These includedtwo heat shock proteins, a vacuolar pyrophosphatase and a protein involved in celldivision. It is suggested that specific grape mRNAs accumulate in response tostresses such as the storage of high concentrations of sugars and rapid cell expansion.These processes occur rapidly during the ripening of berries. Accumulation of specificmRNAs can be attributed to part of the normal ripening developmental programme.

[发布机构] Stellenbosch University