New experimental hosts of Barley yellow dwarf virus among wild grasses, with implications for grassland habitats

Abstract

Barley yellow dwarf virus (BYDV), an economically important virus, infects small grain cereal crops and over 150 other Poaceae species. BYDV infection plays an important role in competition among grasses in non-managed systems, but many grasses remain unexamined as potential BYDV hosts. This study examined grass species that have not been reported as BYDV hosts but are commonly encountered in non-managed grasslands throughout the United States and Canada. Laboratory inoculations with BYDV-PAV using the aphid vector Rhopalosiphum padi were performed to examine the ability of 13 grass species and barley to be infected with the virus; eight of the grass species were not documented previously as virus hosts. Serological and molecular assays were used to confirm BYDV-PAV infection. Plant height, number of leaves, number of tillers and weight were recorded to evaluate susceptibility or sensitivity to BYDV. Infection with BYDV was experimentally achieved for the first time on Achnatherum lettermanii, Achnatherum occidentale, Achnatherum thurberianum, Danthonia intermedia, Poa fendleriana, Sporobolus airoides and Sporobolus cryptandrus, but not on Alopecurus pratensis and Elymus wawawaiensis. Infection was confirmed in Bromus inermis, Elymus elymoides, Poa bulbosa, Poa secunda and Hordeum vulgare, which served as controls. BYDV infection caused reductions in plant height on P. bulbosa and P. fendleriana. BYDV-infected P. secunda had more leaves per plant compared to healthy plants of the same species. BYDV-infected A. lettermanii exhibited reduced dry weight in both below-ground and above-ground tissue. These findings have implications for the management and conservation of grassland habitats.

Non‐cultivated grass hosts of yellow dwarf viruses in Ethiopia and their epidemiological consequences on cultivated cereals

“…MYDV-RMV, BYDV-SGV, BYDV-MAV and CYDV-RPV were, in this order, identified from 36 (17.1%), 20 (9.5%), 12 (5.7%) and 12 (5.7%) samples (Table 3). In another test consisting of 26 grass species (16 forage cereals and 10 grass weeds) ( (Hadi, 2009;Ingwell & Bosque-Pérez, 2014, 2015. Hence, to the best of our knowledge, these grasses are regarded as the first (Bekele et al, 2001(Bekele et al, , 2003.…”

“…anthistrioides , Panicum coloratum , Polypogon monspeliensis , S. pumila , Setaria australiensis and S. polystachya . In addition, these new hosts were cross‐checked against a comprehensive review of alternative hosts of YDVs made by D'Arcy's () and more recent reports (Hadi, ; Ingwell & Bosque‐Pérez, , ). Hence, to the best of our knowledge, these grasses are regarded as the first report of YDV alternative grass hosts in Ethiopia and possible globally.…”

“…A comprehensive review of the YDVs host range was given by D'Arcy () which indicated that these viruses can infect more than 150 species in five of six subfamilies of the family Poaceae . Since then, and with the help of improved diagnostic methods (Hadi, ; Ingwell & Bosque‐Pérez, , ), many new hosts were reported, and the number of alternative hosts continues to rise. In places where the economically important hosts such as wheat, barley or oats are only planted in a specific period in a year, various weed, pasture and range grasses may act as alternative hosts in which the viruses and vectors survive, facilitating introduction of the viruses to new plantings of commercial hosts (D'Arcy, ), provided that the aphid vectors move into these crops from adjacent grasses.…”

“…In places where the economically important hosts such as wheat, barley or oats are only planted in a specific period in a year, various weed, pasture and range grasses may act as alternative hosts in which the viruses and vectors survive, facilitating introduction of the viruses to new plantings of commercial hosts (D'Arcy, ), provided that the aphid vectors move into these crops from adjacent grasses. In addition to its effect on yield and yield components of cultivated cereals, research results envisaged that YDV infection plays an important role in competition among grasses in non‐managed systems (Garrett et al., ; Ingwell & Bosque‐Pérez, ; Malmstrom, ), suggesting that YDV infection influences competitive dynamics between native and invasive grasses and facilitates invasion by non‐native annual weeds (Borer, Hosseini, Seabloom, & Dobson, ; Malmstrom, McCullough, Johnson, Newton, & Borer, ).…”

Interactions betweenMetopolophium festucae cerealium(Hemiptera: Aphididae) andBarley yellow dwarf virus(BYDV-PAV)

“…In summary, our results indicate that M. festucae cerealium , although potentially a threat due to its direct injury to wheat plants, will likely not pose a risk as a virus vector, or because its populations are amplified on BYDV-PAV-infected wheat. Additional work is indicated to determine whether M. festucae cerealium can transmit other B/CYDV species, such as MAV for which M. festucae (unspecified subspecies) is a vector ( Plumb 1974 , 1990 , 1995 ), or SGV, which occurs in perennial grasses of the PNW ( Ingwell and Bosque-Pérez 2015 ). Metopolophium festucae cerealium has been collected from perennial grasses such as Alopecurus pratensis L. in the PNW (S.E.S.…”