An Efficient Procedure for Purification of an Isolate of Peanut Mottle Virus from Wild Peanut and Determination of Molecular Weights of the Viral Components¹

An efficient procedure was developed for purification of peanut mottle virus (PMV) from pea (Pisum sativum cv. Little Marvel) that yielded 10–19 mg virus/ kg infected tissue. Virus was extracted from frozen infected tissue in 0.01 M potassium phosphate buffer, pH 8.0, with 0.001 M dithioerythritol, followed by clarification with chloroform (15%, v/v) and precipitation by KCl and polyethylene glycol. Virus was resuspended in 0.01 M borate-phosphate buffer, pH 8.3, with 0.2 M urea prior to density gradient centrifugation. Purified virus sedimented as a single component with a sedimentation coefficient of 149 S. The molecular weight of the single coat protein was estimated as 36,100 daltons in 12% polyacrylamide gels. The single nucleic acid isolated from PMV on sucrose gradients was degraded by RNase, but not DNase. The molecular weight of the RNA was estimated as 3.1 × 10⁶ daltons on nondenaturing and denaturing sucrose gradients.