Barley Yellow Dwarf Disease in Natural Populations of Dominant Tallgrass Prairie Species in Kansas

Abstract

The grasses Sorghastrum nutans (Indian grass), Schizachyrium scoparium (little bluestem), Panicum virgatum (switchgrass), and Andropogon gerardii (big bluestem) are four of the most common plant species present in a tallgrass prairie (1). Infection with barley yellow dwarf virus (BYDV, family Luteoviridae) is of interest in these species because of the potential effects of the virus on tallgrass prairie plant communities and the potential for tallgrass prairie to function as a reservoir of the virus for infection in wheat or barley fields. In a previous inoculation experiment, an unidentified strain of BYDV transmitted by the aphid species Rhopalosiphum padi was reported to infect S. scoparium but none of the other three grass species (2). We sampled for the presence of five virus strains in at least 50 blooming plants of each grass species in a natural tallgrass prairie stand in August 2000. Samples were collected in watersheds that were designated 1B, 1D, K1A, 20B, and 20C at Konza Prairie Biological Station in the Flint Hills near Manhattan, KS. To detect the virus, we used enzyme-linked immunosorbent assay (ELISA) with antibodies purchased from Agdia (Elkhart, IN). For the PAV, MAV, RMV, and SGV strains, we used double-antibody sandwich ELISA with alkaline phosphatase label. For Cereal yellow dwarf virus (RPV), we used compound direct ELISA with alkaline phosphatase label. The scoring of ELISA results was based on comparison with infected and uninfected control plants of the same species. Symptoms of infection in the field were difficult to interpret visually, since plants in this natural environment often showed multiple symptoms of stress. None of the five strains were detected in 51 individuals of S. nutans. For 50 individuals of S. scoparium, the incidence of infection by the different strains was 4% for MAV, 0% for PAV, 2% for RMV, 0% for RPV, and 58% for SGV. For 51 individuals of P. virgatum, the incidence of infection was 31% for MAV, 0% for PAV, 0% for RMV, 0% for RPV, and 4% for SGV. For 64 individuals of A. gerardii, the incidence of infection was 59% for MAV, 0% for PAV, 0% for RMV, 0% for RPV, and 3% for SGV. The impact of BYDV on these tallgrass prairie species

Reactions of Perennial Grain Accessions to Four Major Cereal Pathogens of the Great Plains

“…Natural inoculum was used in these tests, which may have included a variety of BYDV strains because of proximity to both wheat fields and tallgrass prairie. The dominant BYDV strains differed among prairie grass species in Kansas (16), and it will be useful to determine in future studies whether perennial grains also differ in their reaction to a range of BYDV strains.…”

Interactions Within Susceptible Hosts Drive Establishment of Genetically Distinct Variants of an Insect-Borne Pathogen

“…Coinfections with multiple pathogen species or strains that may vary in virulence are common in many disease systems of humans, other animals, and plants (Chandler et al 1987, Garrett et al 2004, Bell et al 2006, Gó mez et al 2009, Lecoq et al 2011, inevitably leading to interactions between pathogens during transmission and establishment in new hosts. The strength and direction of pathogen interactions can differ within host and vector, potentially exerting opposing influence on overall spread.…”

“…Coinfections of closely related pathogen species or even multiple genetically distinct variants of one pathogen species are common. Examples of plant diseases that commonly occur as coinfections of multiple virus strains or variants are barley yellow dwarf virus, tomato yellow leaf-curl virus, and grapevine leafroll-associated viruses (Garrett et al 2004, Seabloom et al 2009, Jooste et al 2011, Sharma et al 2011, Péréfarres et al 2014.…”

Multi-Year Pathogen Survey of Biofuel Switchgrass Breeding Plots Reveals High Prevalence of Infections by Panicum mosaic virus and Its Satellite Virus

“…Members of the family Luteoviridae, including Barley yellow dwarf virus (BYDV, genus Luteovirus) and Cereal yellow dwarf virus (CYDV, genus Polerovirus) have been identified as pathogens of switchgrass (Garrett et al 2004). BYDV and CYDV are positive-sense, single-stranded RNA (+ssRNA) viruses that rely on aphid vectors for plant-to-plant transmission.…”

“…Multiple strains of these viruses have been identified and characterized by their strainspecific association with key aphid vectors. BYDV strains MAVand PAV and CYDV strain RPV are known pathogens of switchgrass in the field and rely on persistent transmission by multiple species of aphid vectors including the grain aphid (Sitobion avenae), the bird cherry-oat aphid (Rhopalosiphum padi), and rose grain aphid (Metopolophium dirhodum) (Garrett et al 2004;Gray and Gildow 2003). Additional +ssRNA viruses of switchgrass include Sugarcane mosaic virus (SCMV, genus Potyvirus) and Switchgrass mosaic virus (SwMV, putative genus Marafivirus) (Agindotan et al 2010(Agindotan et al , 2013b.…”