Abstract
'St. Augustine decline' is a viral disease associated with St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, a turfgrass common to the Gulf Coast region of the United States. A survey of 204 plants from two locations in southeast Texas indicates that this disease is a result of an infection with Panicum mosaic virus (genus Panicovirus; family Tombusviridae) (PMV), or in any combination with satellite panicum mosaic virus (SPMV), and/or with its satellite RNAs (satRNAs). In the field, leaf symptoms representative of PMV infections with or without cc-infections by SPMV or satRNAs ranged from a severe bleaching to a mild chlorotic mottle. However, after five months growth in the greenhouse, these symptoms shifted towards a relatively homogeneous chlorotic mottle phenotype, suggesting the influence of environmental conditions. Ribonuclease protection assays (RPAS) indicated a high degree of genetic variability in PMV satRNAs infecting St. Augustinegrass at the College Station (CS) and Corpus Christi (CC) locations. The RPAS grouped satRNAs according to the place of origin, either CS or CC with only 6 exceptions out of 100 satRNAs. Two satRNAs collected in CC were placed in the CS cluster and four collected in CS were placed in CC cluster. Hence, these data shown that different but overlapping population of PMV satRNA can be found in CS and CC.
Cabrera Perez, Over (1999). Field distribution and genetic variability of Panicum mosaic virus satellite RNAs in St. Augustine decline. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1999 -THESIS -C33.