Inducing of systemic acquired resistance (SAR) factors through PVY systemic infection in Samsun tobacco containing N resistant gene

Systemic Acquired Resistance (SAR) is a kind of plant resistance response to systemic viralinfections. In this study the expression levels of factors that are responsible for hypersensitive response to TMV infection and factors that are involve in SAR resistant response to PVY° infection was studied. For that, we used non transformed N. tabacum cv. Samsun NN and susceptible transgenic tobacco plants in which the RDR6, mRNA transcript levels was low in the cells. Toward this aim quantitative expression of resistance key genes including ERF5, AOX1 and IVR were assessed by semi-quantitative RT-PCR method. The salicylic acid biosynthesis and its concentration within viral treated leaf tissues were evaluated by using salicylic acid reporter bacteria Acinetobacter sp. ADP1. The xpression of PR-1 protein within inoculated plants was also assessed by western blott analysis. The peroxidase enzyme specific activity was evaluated. These results indicate, that SAR resistance response may be activated in response to the biotrophic stresses like PVY systemic infection in plants. This activation is not exclusive for early expression of key SAR factors but also it is need for expression of the key genes responsible in SAR signaling pathway. These results indicate that RDR6 may be a key gene in SAR signaling cascade within plant cells in which its impairment can disturb the SAR inhibitory effects in PVY infected plants. Due to non effective function of dominant single resistant genes for making resistance plants to PVY infection, it is suggested to use recessive resistance genes for development of PVY resistant transgenic plants in which the systemic acquired resistance pathways are active.