Grapevine grafting: scion transcript profiling and defense-related metabolites induced by different rootstocks.. Vitis vinifera

Genotype, climate, soil qualities, and rootstocks are among the main factors that influence grape development as well as fruit and wine composition. In this work, the rootstock/scion interactions were studied using transcriptomic and metabolic approaches on leaves of Gaglioppo variety, grafted onto thirteen different rootstocks growing in the same locations. The experiments were performed in a vineyard in the south of Italy, characterized by the Mediterranean climate with warm and dry summers. Whole leaf transcriptome of ‘Gaglioppo’ grafted on five selected rootstocks showed high variability in gene expression. In particular, significant modulation of transcripts linked to primary (e.g. carbohydrate and transport) and secondary metabolism (e.g. phenylpropanoids pathways and response to stress) was observed. Interestingly, genes involved in the priming defense responses (e.g stilbenes and defense genes) were strongly activated in some graft combinations. These results were further confirmed by the quantification of stilbene contents. According with these observations, the leaves of ‘Gaglioppo’ grafted on 1103 Paulsen showing the lowest levels of stilbene synthase transcripts and stilbene metabolites, reveal the greater sensitivity to downy mildew in in vitro assay. This study carrying out an extensive analysis of rootstock effects to scion leaves open a useful way to unravel this complex interaction Overall design: Differential expression analysis of Gaglioppo variety grafted onto five different rootstocks