Abstract

Chile has a remarkable fruit export industry, in particularly table grapes. The fruit business relies in the continuous consumer acceptance of our products in order to keep competitiveness. Nowadays, consumers are demanding high quality fresh products on base of multiple attributes. In the case of table grape the berry firmness is highly relevant because consumers prefer crunchy berries, and high firmness is associated with freshness. However, table grape berry firmness represents a problematic issue, in particular in our most important variety Thompson Seedless, which usually showed soft berries at harvest or during postharvest storage. However, this situation became more challenging since our country is located significantly far away of the important markets, and fruits are alive products that undergo constant modifications due to interaction with the environment. In our previous research we studied transcriptomic changes linked to berry firmness. Several transcripts associated to primary and secondary metabolism changed during berry growing, ripening and postharvest and these changes can be linked to berry firmness modification. In addition, these processes can be variety dependent, or be modified by agroecological conditions and cultural practices. It is clear that to control all these variables is complicated, but agronomists routinely are dealing with these elements in order to produce high quality table grape, although the final results at harvest, or most important to consumers, is rarely known in advance. Therefore, any tool designed to reduce the uncertainty and help to take decisions ahead in time is quite welcome. This consideration has pushed many researchers to look for predictors that help to diminish the insecurity, unfortunately with low success. However, nowadays we are able to use new high throughput screening techniques, which allow us to get vast information related with changes of gene transcripts, proteins abundance and metabolite profiles in fruit samples. Taking account that if we are capable to get access to large amount of data provided by omics, and we have the bioinformatics tools to do correlations between these datasets and phenotypic (quality traits), it is feasible to identify biomarkers that can help us to predict changes. In this way, if some kind of correlations could be established between, for example, a mRNA(s) or specific compound(s) at berry development with fruit firmness at harvest or postharvest, these in theory could help us to predict the berry firmness at distant markets or after prolong postharvest storage. In addition, if these candidates could be independent of the season or agroecological condition, the value of them would increase significantly proving us new tools to know on beforehand some idea of berry firmness, or overall quality. Given these assumptions we propose that we are able to find biomarker candidates (gene transcripts and / or metabolites) in Thompson Seedless table grapes that could predict the characteristics of berry firmness at harvest and postharvest storage. The strategy to find such candidates will be based on the transcriptomic and metabolomic analyses of Thompson Seedless berries at developing and harvest stages. The samples of T. Seedless (the most important variety in Chile) will be obtained from different agroecological regions (north, central, south) and seasons. Additionally, an exhaustive phenotyping will be carried with emphases on berry firmness at harvest and postharvest storage. Once the information of omics plus phenotyping will be collected using in silico bioinformatic approaches base on statistic models, the datasets will be correlated leading to the identification of candidates