A controlled environment test for resistance to Soil‐borne cereal mosaic virus (SBCMV) and its use to determine the mode of inheritance of resistance in wheat cv. Cadenza and for screening Triticum monococcum genotypes for sources of SBCMV resistance

Abstract

Several wheat genotypes, including eight with known field responses, were evaluated for their reaction to Soil-borne cereal mosaic virus (SBCMV, genus Furovirus) by growing in naturally infested soil under controlled environment conditions. Virus antigen titres in the foliage 8-9 weeks after sowing mostly reflected the field responses, showing that growth chamber-based tests can be used to improve the speed and reliability of germplasm screening. Such tests were used to determine the mode of inheritance of the SBCMV resistance in cv. Cadenza, commonly used in UK wheat-breeding programmes. One hundred and eleven doubled haploid (DH) lines derived from an F 1 of a cross between cvs Cadenza (resistant) and Avalon (susceptible) were evaluated. This DH population segregated for the reaction to SBCMV in a ratio of 1 : 1 (resistant : susceptible). This suggests that the SBCMV resistance is controlled by a single gene locus. As a first step towards identification of new sources of improved SBCMV resistance (e.g. immunity) as well as sources of the resistance to the virus vector, Polymyxa graminis , a set of 26 Triticum monococcum lines of diverse geographical origin was also screened. Most lines were susceptible to SBCMV, but one line of Bulgarian origin was resistant to the virus and possibly partially resistant to the virus vector.

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

“…Moreover, uneven distribution of fertiliser in the field, nutrient imbalance or winter injuries may cause symptoms (e.g. leaf mosaic, stunting) in pathogenfree plants that could be mistaken for soilborne virus disease (Kanyuka et al 2004). Indeed, SBCMV, WSSMV, BaMMV and BaYMV were not detected using F(ab') 2 ELISA, DAS-ELISA or the more sensitive RT-PCR tests in the bait plants grown in 26 soil samples collected from Eskisehir province.…”

“…The plants were watered generously every other day with a nutrient solution (Adams et al 1986). Approximately 4 weeks post inoculation, when the plants had reached growth stage 4 on the Feekes scale (Large 1954), each was trimmed to 5 cm from the soil level to stimulate systemic virus movement (Kanyuka et al 2004), and harvested 4 weeks later. These plant samples were kept at -20°C until being analysed for the presence of soilborne viruses using ELISA.…”

“…All bait plants were watered every other day with a nutrient solution (Adams et al 1986). These conditions were chosen on the basis of data from similar, previous glasshouse-based experiments with SBWMV (Armitage et al 1990;Kanyuka et al 2004) and P. graminis transmitted bymoviruses of barley (Adams et al 1986). The bait plants were trimmed to about 5 cm from the soil level at~4-5 weeks post inoculation, and allowed to grow for additional 4 weeks.…”

“…F(ab') 2 ELISA utilised in-house produced virus species specific rabbit IgG and F(ab') 2 fragments of IgG for SBCMV, BAMMV and BaYMV, and was performed essentially as described in Kanyuka et al (2004). Root extracts of the bait plants were prepared using Juice Press (Erich Pollähne GmbH, Wennigsen, Germany) in the presence of 10 volumes of extraction buffer per 1 g fresh weight of root material.…”

“…6, 75, 91, 106, 107 and 500, which had previously tested positive for one or more virus species in DAS-ELISA and / or F(ab') 2 ELISA. Total RNA was extracted from 100 mg of frozen tissues as described previously (Kanyuka et al 2004). …”