Grapevine EDS1 regulatory region and salicylic acid accumulation: pathway components differently linked to powdery mildew resistance

In grapevine, the defense regulator ENHANCED DISEASE SUSCEPTIBILITY (EDS) is present as a multi-member gene family contributing to basal defense in plants. EDS1 is highly conserved and functional in both, Vitis vinifera ‘Cabernet Sauvignon’ and Vitis aestivalis ‘Norton’. However, whereas the regulation of EDS1 – regarding tissue specificity and transcript level – may be a key factor for powdery mildew (PM) resistance in V. aestivalis ‘Norton’, this is not the case in V. vinifera ‘Cabernet Sauvignon’, which is susceptible.
The putative promoter sequences of the EDS1 genes (pEDS1) from V. vinifera ‘Cabernet Sauvignon’ and V. aestivalis Norton were bioinformatically analyzed to predict transcription factor binding sites (TFBS) and higher order regulatory models.
The promoter sequences contain some conserved but also highly variable regions as well as a different set of TFBS and regulatory models.
In pEDS1 from V. vinifera ‘Cabernet Sauvignon’, four higher order regulatory models are predicted, while in pEDS1 from V. aestivalis ‘Norton’ five different putative models are present.
The variations within the regulatory regions of pEDS1 are presumably responsible for specific EDS1 expression.
Besides PM resistance, also salicylic acid (SA) signaling and the degree of accumulation in leaves is thought to be associated with EDS1 expression.
Consequently, the SA content was determined in leaves of eight PM resistant V. aestivalis genotypes and six V. vinifera grapevine genotypes, which are either susceptible, tolerant, or resistant.
Further, a V. vinifera backcross containing the resistance locus from Muscadinia was analyzed. V. vinifera genotypes containing PM resistance showed higher SA concentrations compared to susceptible cultivars, while in V. aestivalis and the Muscadinia × V. vinifera backcross genotype, SA concentrations are similar to those found in susceptible V. vinifera genotypes.
Hence, SA accumulation and PM resistance may be not directly linked, but dependent on the genetic background.

IV International Symposium on Horticulture in Europe – SHE2021

M.H. Hagemann, E. Sprich, P. Winterhagen

grapevine, Vitis vinifera, resistance breeding, powdery mildew, salicylic acid, EDS1

https://doi.org/10.17660/ActaHortic.2021.1327.87