Location: Wheat, Sorghum and Forage ResearchTitle: Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance
|ALI, NIAZ - University Of Leicester|
|HESLOP-HARRISON, JS PAT - University Of Leicester|
|AHMAD, HABIB - Hazara University|
|HEIN, GARY - University Of Nebraska|
|SCHWARZACHER, TRUDE - University Of Leicester|
Submitted to: Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2016
Publication Date: 6/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62795
Citation: Ali, N., Heslop-Harrison, J., Ahmad, H., Graybosch, R.A., Hein, G.L., Schwarzacher, T. 2016. Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance. Heredity. Available: http://www.nature.com/hdy/journal/vaop/ncurrent/full/hdy201636a.html#top.
Interpretive Summary: Wheat streak mosaic virus, transmitted by wheat curl mite is one of the most important yield limiting diseases of wheat , with significant losses to both forage and grain. It was reported first in the United States, and has since spread widely across the wheat growing world and can infect both winter and spring wheat cultivars. Volunteer wheat, time of infection, temperature and genotypes used all contribute to severity of the disease. Greenish yellow streaks and chlorosis are common visible symptoms of WSMV, while stunted growth, low root biomass and reduced water uptake efficiency affects yields significantly. Importantly both, WSMV and the mite vector survive during the late summer on 'green bridges' provided by volunteer wheat and other grasses. WSMV can also infect rye, rye grass, barley, wild oats and other grasses. Some of our high yielding cultivars suffer from low resistance, while many of the highly resistant cultivars show poor agronomic performance Genes from wild and domestic relatives of wheat have been introduced via traditional cross-breeding and allow the transfer of major disesase resistance traits. In this investigation, it was shown enhanced virus resistance could be transferred multiple species including rye and intermediate wheat-grass. Future breeding efforts will result in wheat cultivars deploying these enhanced resistance traits in Great Plains production systems.
Technical Abstract: Pyramiding of alien-derived Wheat streak mosaic virus (WSMV) resistance and resistance enhancing genes in wheat is a costeffective and environmentally safe strategy for disease control. PCR-based markers and cytogenetic analysis with genomic in situ hybridisation were applied to identify alien chromatin in four genetically diverse populations of wheat (Triticum aestivum) lines incorporating chromosome segments from Thinopyrum intermedium and Secale cereale (rye). Out of 20 experimental lines, 10 carried Th. intermedium chromatin as T4DL*4Ai#2S translocations, while, unexpectedly, 7 lines were positive for alien chromatin (Th. intermedium or rye) on chromosome 1B. The newly described rye 1RS chromatin, transmitted from early in the pedigree, was associated with enhanced WSMV resistance. Under field conditions, the 1RS chromatin alone showed some resistance, while together with the Th. intermedium 4Ai#2S offered superior resistance to that demonstrated by the known resistant cultivar Mace. Most alien wheat lines carry whole chromosome arms, and it is notable that these lines showed intra-arm recombination within the 1BS arm. The translocation breakpoints between 1BS and alien chromatin fell in three categories: (i) at or near to the centromere, (ii) intercalary between markers UL-Thin5 and Xgwm1130 and (iii) towards the telomere between Xgwm0911 and Xbarc194. Labelled genomic Th. intermedium DNA hybridised to the rye 1RS chromatin under high stringency conditions, indicating the presence of shared tandem repeats among the cereals. The novel small alien fragments may explain the difficulty in developing well-adapted lines carrying Wsm1 despite improved tolerance to the virus. The results will facilitate directed chromosome engineering producing agronomically desirable WSMV-resistant germplasm.