Gene Expression Analysis of Rugose Wood Affected Autografts of Grapevine Cultivar Refosk

Rugose wood complex (RWC) is one of the most important graft-transmissible grapevine diseases. Despite the fact that particular viruses are associated with the RWC, its aetiology remains unexplained. The aim of the study was to find out if the appearance of RWC could be related to the biological processes that are triggered by grafting. RNA samples were obtained from autografts which were made with green shoots of RW-affected vine 'Refošk' 38 VIII/44, while for controls green shoots of vine with no RW visible symptoms 'Refošk' 43 VII/113 were used. Samples for RNA extraction were taken 3, 7 and 14 days after grafting. Eighty-six differentially expressed transcripts were obtained with differential display analysis. BLAST analysis (12Xv1 assembly version, NCBI RefSeq Database, NCBI NT Database) revealed 65 genes (3 genes were represented by 2 transcripts, 4 transcripts were aligned to grapevine genomic sequence, 4 transcripts had an unknown sequence) that were differentially expressed. Ten genes were common to both biotypes, but they were identified as differentially expressed over the time course. Graft wounding and the healing process result in the activation of many different genes, including those involved in the process of transcription and translation, which was also confirmed by our results. The identification of several differentially expressed genes involved in the oxidation-reduction processes and in the stress response related processes indicates that physiological response to stress, caused by grafting and graft union formation processes, could be a possible causal agent of the rugose wood disease.