Transcriptome profiling of GTDs symptomatic vs. asymptomatic grapevine plants
Grapevine trunk diseases (GTDs) have become a major concern to viticulture worldwide, causing a high economic impact on yield and vineyard longevity in all growing areas. The prevalence of GTDs is increasing and, together with the absence of effective treatments, is currently one of the major challenges for viticulture sustainability. Given the urgent need to identify and develop new sustainable and effective protection strategies, a better understanding of grapevine defence mechanisms is crucial to develop more tolerant plants and provide new insights for disease management. This study explored the transcriptomic profile of GTDs symptomatic and asymptomatic plants of 'Trincadeira', a tolerant cultivar, and 'Alicante Bouschet', a susceptible cultivar to GTDs, using next-generation sequencing technology. RNA-seq yielded 1 598 differentially expressed genes (DEGs) between the two cultivars, and 64 DEGs between the groups with different symptomatology, regardless of the cultivar. Transport was revealed as the main biological process involved, generally activated in the susceptible cultivar 'Alicante Bouschet', suggesting that the DEGs associated with these processes may play an important role in disease development. Contrarily, the relative tolerance of 'Trincadeira' to this disease complex might be supported by the activation of secondary and hormonal metabolism and the differential expression of a set of defence-related genes, including resistance genes, which may act as key factors to limit GTDs infection. Furthermore, this study points to an important role of PER42 gene in the inhibition of GTDs symptoms. Our results provide new insights into the resistance mechanisms of grapevine to GTDs and may help to explain the different susceptibilities of grapevine plants to GTDs. To the best of our knowledge, this is the first time that the expression of grapevine defence-related gene expression has been studied in response to different GTDs-associated fungal infections under natural field conditions. We highlight the importance of these studies for the identification of candidate genes that may allow the development of new strategies to incorporate new sources of resistance. The activation or inhibition of potential plant response regulators can be used to promote resistance, thus providing sustainable and effective alternatives to successfully manage GTDs. Overall design: Comparison of the transcriptomic data of GTDs symptomatic and asymptomatic grapevine plants from two different cultivars with different susceptibility patterns to this disease