Genetic Diversity of Panicum mosaic virus Satellite RNAs in St. Augustinegrass

ABSTRACT St. Augustine decline is a viral disease caused by Panicum mosaic virus (PMV) alone or in combination with a satellite virus (SPMV) and/or satellite RNAs (satRNAs). A ribonuclease protection assay (RPA) was used to evaluate the genetic diversity of PMV satRNAs isolated from 100 naturally infected St. Augustinegrass plants (Stenotaphrum secundatum). Distinctive satRNA RPA profiles were observed for 40 of 52 samples from College Station (CS) and 37 of 48 samples from Corpus Christi (CC), Texas. A dendrogram constructed from the RPA data revealed that satRNAs were grouped in two distinct clusters based on their place of origin. From 100 samples, only 4 satRNAs from CS were placed in the CC group, and only 2 satRNAs from CC were placed in the CS group. The data show that there is genetic variability in PMV satRNAs in naturally occurring infections, and distinct geographically separate populations can be identified from CC and CS.