Confirmation of Polymyxa graminis as a Vector of Wheat Spindle Streak Mosaic Virus

Abstract

Wheat spindle streak mosaic virus was transmitted via isolates of each of the zoosporic fungi were cultured on wheat water from soil-free roots of wheat plants infected by growing infected with the virus by sap inoculation of leaves, the virus in infective soil, but not from plants grown in sterile soil and was transmitted by root association in sand only from plants infected with the virus by sap inoculation of the leaves. The infected with P. graminis. The optimum temperature for zoosporic fungi Lagena radicicola, Olpidium brassicae, transmission of the virus in soil, 15 C, is above the optimum Polymyxa graminis, Rhizophydium graminis, and Pythium for the development of the virus, 10 C, but within the lower spp. usually were present in the roots of plants infected from range of temperatures favorable for the development of P. soil, and in the roots of most plants in 10 sets infected graminis. successively by root association in sterilized sand. When Wheat spindle streak mosaic (WSSM) is widespread in transmission, and to determine if any of these fungi some years in most fields in areas of southern Ontario transmitted WSSMV. where winter wheat is grown most intensively (10). It has been reported in several central and northeastern States MATERIALS AND METHODS of the USA, in France, and recently in India (1, 14). It is Soil for most of the experiments reported here was a caused by a soil-borne virus, WSSMV, with very long, sandy loam collected at the Central Experimental Farm, filamentous particles, quite distinct from the short rod-Ottawa, from a field in which winter wheat had been like particles of soil-borne wheat mosaic virus (WSBMV) grown every 3rd yr starting in 1952. By 1967, plants with (4), which has not been found in Ontario and was not symptoms of WSSM were observed in this field. detected in any of the plants grown in soils used in these Subsequently winter wheat was planted each year to build experiments. up and maintain a high level of infectivity. The soil was Because a zoosporic fungus, Polymyxa graminis Led. collected in October, dried on a greenhouse bench, sifted has been associated with the transmission of WSBMV (4, to break down the lumps, and stored dry in a greenhouse 9), this fungus has been a prime suspect as a vector of where temperatures ranged from about 15 to 30 C. WSSMV. Although P. graminis usually has been found Winter wheat (Triticum aestivum 'Kent') was used as in the roots of wheat plants infected with WSSMV the test host and for multiplying the virus and culturing wherever the disease occurs, other fungi that infect wheat the zoosporic fungi. Wheat was infected from soil by roots in similar ways also generally are present, hence sowing 10-15 seeds in 7.5-cm diameter pots of the test soil, they also were suspect as vectors. One of these, Olpidium watering moderately, and growing at 15 C with about brassicae (Wor.) Dang., is a vector of several other viruses 12,000 lux of light for 12 hr per day, genereally for 21 (7). The other suspects included Rhizophydium graminis days, but...

Mapping a gene conferring resistance to Wheat yellow mosaic virus in European winter wheat cultivar ‘Ibis’ (Triticum aestivum L.)

“…WYMV is a soilborne pathogen vectored by the fungus-like organism Polymyxa graminis (Inouye 1969), and the disease is characterized by yellow-striped leaves and stunted spring growth, which results in severe yield loss. Symptoms of WYMV are similar to those caused by Wheat spindle streak mosaic virus (WSSMV) in North America and Europe, which is also transmitted by P. graminis (Slykhuis and Barr 1978;Nolt et al 1981). WYMV and WSSMV are closely related bymoviruses that are distinguished on the basis of their nucleotide sequences Xiaoyun et al 1998).…”

A one step real-time RT-PCR assay for the quantitation of Wheat yellow mosaic virus(WYMV)

“…Filamentous viruses transmitted by P. graminis cause similar diseases of wheat in Europe, Asia and North America [7,8]. These viruses have been described as Wheat spindle streak mosaic virus (WSSMV) and WYMV in different countries [7,9,10]. Until now, the virus causing wheat soil-borne mosaic diseases has been identified as WYMV in most areas of China [11,12].…”

Investigation of soilborne mosaic virus diseases transmitted by Polymyxa graminis in cereal production areas of the Anatolian part of Turkey

“…In earlier growth chamber studies, Slykhuis and Barr (1978) determined the optimum temperature range for development of P. graminis in wheat roots to be 15°to 22°C, the optimum temperature for transmission of WSSMV to be 15°C, and the optimum temperature for symptom development to be 10°C. In the current study, no virus symptoms were seen on the bait plants grown at constant 12°C or 20°C day / 16°C night temperature regimes.…”