Ethylene signalling receptors and transcription factors over the grape berry development: gene expression profiling

The ethylene signalling pathway has never been fully described in grapes. Regarded as a non-climacteric fruit, grape berry seems to ripen independently to ethylene, however 1-methylcyclopropene (1-MCP), a specific inhibitor of ethylene receptors has been shown to alter berry ripening processes. Here, we report profiles of transcript abundance of various receptors and transcription factors, associated with ethylene signalling, throughout berry development. Transcript abundance of ortholog VvETR2 gene showed a transient peak at the inception of ripening in 'Cabernet Sauvignon' berries coinciding with an internal ethylene peak, prior to colour changes. The transcripts of other orthologs such as VvRTE1 and VvEIN4 steadily increased over the berry development, while VvERS1 ortholog transcripts exhibited a peak of accumulation only when the berries were fully coloured. Finally, mRNAs of two transcription factors, VvEIN3 and VvMADS4, showed strong accumulation during the late phase of berry ripening. We also observed inflections of mRNA accumulation after incubating berry clusters with ethylene and 1-MCP (inhibitor of ethylene action). The main effect was observed with VvEIN3 transcripts that showed a significant up-regulation after incubation with 1-MCP. Furthermore, other transcript levels (VvETR2 and VvCTR1) were also increased by exogenous ethylene, once the colour change was initiated ( i.e. 10 to 11 weeks after bloom). Some studies have already indicated that non-climacteric fruits shared signalling pathways with climacteric fruits. However, most differences between these ripening classifications remain poorly described at the genetic/molecular level. This data set will contribute to a better understanding on potential involvements of ethylene signalling in a non-climacteric fruit such as grape berry.