An Improved Purification Procedure for Grapevine Leafroll Associated Viruses

¹ USDA-ARS University of California, Davis CA 95616.
² Department of Plant Pathology, University of California, Davis CA 95616.

Higher yields of purified grapevine leafroll associated viruses (GLRaV) types 1 and 2 were consistently realized when an acidic extraction buffer [0.5 M potassium phosphate, pH 6.4; 4% polyvinyl polypyrrolidone (PVPP), without bentonite] was used. In contrast, yield of purified viruses was problematical using 0.5 M Tris- HCl buffer, pH 8.2, PVPP, either with or without bentonite. Relative virus yields were determined by ELISA. The consistency in virus yields was probably due to increased activity of the polyphenol absorbent, PVPP, when it was suspended in a slightly acidic solution. For GLRaV-3, yields of purified virus were somewhat comparable irrespective of extraction buffer or bentonite.