ABSTRACT
KEY MESSAGE: Stably expressed type I and type II resistance QTL were identified using two Yangmai 158-derived RIL populations, and plant-height and flowering-time QTL intervals detected did not contribute to the FHB resistance variations. Yangmai 158 (Y158) is an elite wheat cultivar widely grown in China with stable Fusarium head blight (FHB) resistance. To enrich the genetic basis underlying FHB resistance, QTL mapping was conducted using two recombinant inbred line (RIL) populations derived from crosses of Y158 with susceptible lines Annong 8455 and Veery. Survey with makers linked to Fhb1, Fhb2, Fhb4 and Fhb5 in resistance cultivar Wangshuibai indicated that both Y158 and the susceptible lines do not contain these QTL. The RIL populations were surveyed with 65 PCR markers and 55 K chip, which generated 23,159 valid marker data, to produce genetic maps for whole genome scanning of quantitative trait loci (QTL). A total of six QTL, all with the Y158 alleles for better resistance and including one stably expressed QTL for type I resistance (Qfhi.nau-2D) and one stably expressed QTL for type II resistance (Qfhs.nau-2A), were identified. Moreover, taking advantage of the great genetic variations in plant height and flowering time, QTL conditioning these two traits were determined. Of six plant-height QTL and three flowering-time QTL intervals detected, none were associated with FHB resistance. The FHB resistance QTL in Y158 were shown to be useful alternatives in FHB resistance breeding programs. The SNP markers flanking Qfhs.nau-2A and Qfhi.nau-2D have been converted to breeder-friendly PCR-based markers to facilitate their applications.
Subject(s)
Chromosome Mapping/methods , Chromosomes, Plant/genetics , Disease Resistance/immunology , Fusarium/physiology , Plant Diseases/immunology , Plant Proteins/metabolism , Triticum/genetics , Disease Resistance/genetics , Gene Expression Regulation, Plant , Plant Diseases/genetics , Plant Diseases/microbiology , Plant Proteins/genetics , Triticum/growth & development , Triticum/microbiologyABSTRACT
Head or ear blight, mainly caused by Fusarium species, can devastate almost all staple cereal crops (particularly wheat), resulting in great economic loss and imposing health threats on both human beings and livestock1-3. However, achievement in breeding for highly resistant cultivars is still not satisfactory. Here, we isolated the major-effect wheat quantitative trait locus, Qfhs.njau-3B, which confers head blight resistance, and showed that it is the same as the previously designated Fhb1. Fhb1 results from a rare deletion involving the 3' exon of the histidine-rich calcium-binding-protein gene on chromosome 3BS. Both wheat and Arabidopsis transformed with the Fhb1 sequence showed enhanced resistance to Fusarium graminearum spread. The translation products of this gene's homologs among plants are well conserved and might be essential for plant growth and development. Fhb1 could be useful not only for curbing Fusarium head blight in grain crops but also for improving other plants vulnerable to Fusarium species.
