Abstract

Grapevine fanleaf virus (GFLV) is the causal agent of a widespread disease that affects vineyards. Since it is difficult to culture viruses, the availability of an easy and efficient method of virus maintenance in the laboratory would be of interest to virologists. The objective of this research was to determine an adequate culture medium that promotes callus growth and permits the preservation of GFLV on Vitis vinifera tissue. Fragments of in vitro cultured leaves (25 mm2), originated from Cabernet Sauvignon positive for GFLV, were cultivated on a Murashige and Skoog (1962) medium, and the callus was monitored for the presence of GFLV every two weeks using ELISA. Higher 2,4-D concentration induced a higher growth, particularly when combined with a low BA concentration. The medium enriched with 1.0 ppm of 2,4-D combined with 0.5 ppm of BA showed the best result, with the callus area reaching more than 250 mm2 after 8 weeks in culture. ELISA absorbance observed on callus tissues during the whole period was, at least, three times higher than that observed on leaves positive for GFLV kept either in vivo or in vitro and more than 18 times higher than that of the negative control. Any remarkable difference in absorbance was recorded during the period of callus cultivation. It was concluded that the viral load on the callus was not affected during this time, suggesting that this kind of in vitro culture is an efficient method to preserve GFLV. © 2008 Akadémiai Kiadó.