The Rupestris stem-pitting associated virus (RSPaV) is reported to cause stem pitting disease in grapevines (Vitis spp.). This work studies an RSPaV-isolate found infecting grapevine cv. C. Franc in the State of Rio Grande do Sul, Brazil. This isolate was detected biologically, by grafting on Rupestris du Lot grapevine indicator, in 26.2% of the analysed samples. The partial replicase gene sequence of the Southern Brazilian RSPaV isolate, with 831 nucleotides amplified by RT-PCR and 276 deduced amino acids, showed high identities of nucleotides (98.1%) and deduced amino acids (99.6%), with two RSPaV North American isolates. The RSPaV studied showed low homology (37-41%) with other members of the genus Foveavirus. Most of the virus-free rootstocks grafted with RSPaV infected scions showed photosynthetic potential reduction (2.68 to 5.12 times) and dark respiratory rate increase when compared to healthy ones, emphasizing the potential negative impact of this virus on grapevine production.
