Phytoalexin stilbenoids of Saperavi and Rkatsiteli(Vitis vinifera L.) as biomarkers of resistance to Crown gall infection (Agrobacterium tumefaciens)

We have studied the correlation between the phytoalexin stilbenoids synthesis and the level of bacterial and fungal attacks. The paper shows the results of the study related to crown gall infection in different viticulture areas (locations) of Georgia. In concert: for Saperavi - Mukuzani and Napareuli, for Rkatsiteli - Tsarapi and Tibaani. In April 2024 we infected vine trunks with water suspension of “Agrobacterium tumefaciens” under different soil and climatic conditions and we observed the development of diseases in the period of April- October. In experimental vineyards were found out dominant phytoalexin stress- metabolites stilbenoids trans-resveratrol and trans- ɛ -viniferin in the infected vine trunks of Saperavi and Rkatsiteli. Stilbenoids concentration changes were observed under the vine varieties and soil-climatic factors. The impact of mentioned factors were established with different experiments carried out in the lab and in the vineyard. The results are important data for considering the stilbenoids as biomarker of Saperavi and Rkatsiteli vine varieties for their resistance against crown gall disease.