Sulphur dioxide evokes large scale reprogramming of the grape berry transcriptome

Sulphur is used as a food preservative, especially throughout the table grape and wine industries, <br></br>however there is increasing concern as to the health rises associated with human consumption. <br></br>Thus, we investigated the transcript abundance changes in grapes treated with sulfur dioxide and <br></br>other preservative compounds, compared to control treatments. Export quality, red-skinned ‘Crimson<br></br> Seedless’ grapes (Vitis vinifera L.) were harvested at commercial maturity from one vineyard <br></br>in the Swan Valley region of Western Australia. At least 15 kg grapes per treatment were <br></br>completely immersed in the treatment solution (? 1 min) and allowed to dry on racks before <br></br>being weighed in to 7 x 2 kg lined export cartons, without sulphur pads. Once packed, cartons <br></br>were immediately placed in 2 °C storage for up to 56 days and once cool, commercial <br></br>SO2-generating pads were placed into cartons for SO2 treatment. The salicylic acid (SA,<br></br> 25 mM), methyl jasmonate (MJ, 5mM) and their combination (25 mM SA + 5 mM MJ) were <br></br>dissolved in 0.5 % (v/v) dimethyl sulphoxide (DMSO). A 0.5 % solution of DMSO was used<br></br> as a control treatment. An additional, untreated control for sulphur-treated berries was used.<br></br>Microarrays were performed in duplicate for the 6 treatments, Sulfur dioxide (plus untreated <br></br>control), SA, MJ, and the combined SAMJ treatment (plus DMSO control) on grape berries <br></br>after 21 days of treatment post harvest. The results indcate a large scale re-programing of <br></br>the grape berry transcritpome, similar to that which has been observed for prolonged <br></br>exposure to harsh oxidative stress conditions.

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