Plant viruses can cause up to 15% yield loss in agriculture. Nowadays prevention (reducing vector abundance, and choosing the optimal sowing-time) is the only way of antiviral defence. Chemical plant defence has double costs: financial and ecological, so the best solution would be production and breeding of virus resistant crop varieties.WDV (wheat dwarf virus) - a member of Geminivirideae family– causes significant damages in Hungarian wheat and barley cultivation. Over the past years our research group have made an attempt to produce WDV tolerant barley lines with artificial microRNA (amiRNA) technology. Besides this system’s relative simplicity, it has several drawbacks too: It affects only the transcripts of WDV genome (Kis et al. 2016). In contrast to amiRNA technology, CRISPR/Cas9 (a genome editing tool from bacteria) can directly cut and inactivate the viral DNA. To increase WDV tolerance in barley, we created the WDVGuide4Guard genetic construct. According to our investigations the transgenic barley lines containing this construct are WDV tolerant.