Identification of a potential source of complete resistance to soilborne wheat mosaic virus in a wheat-Thinopyrum intermedium addition line

Soilborne wheat mosaic virus (SBWMV)is a Furovirus transmitted by the plasmodiophoraceous fungus, Polymyxa graminis. Resistant cultivars of wheat (Triticum aestirum) to SBWMV have already been described. The resistance encountered mostly includes root infection without viral migration to foliage. In this study, the reaction ofaddition lines (L1, L1S, L2, L3, L4, L7,) and the partial amphiploid derived from wheat (Vilmorin 27) and Thinopyrum intermedium has been evaluated. Lines L1, L3, L7, L1S and cultivar Vilmorin 27 are susceptible to SBWMV. Lines L4 and TAF 46 are root infected only. Chromosome 4Ag 1 in L4 is thought to have an equivalent reaction to that one found in the mostly encountered resistance. Another type of resistance in a wheat line (L2) with the added chromosome 3Agi of Th. intermedium has been characterized. In this line, L2. no SBWMV particles were detected on their roots by enzyme-linked immunosorbent assays. Contrary to observations made on lines L1, L1S, L3, L4, L7, amphiploid TAF 46, and the wheat cultivars (Festival, Fandango. Vilmorin 27). no resting spores of P. graminis were found on roots of L2 2 months post inoculation. It is suggested that the disomic addition line L2 is immune to SBWMV.