Chromosome telosome 1StL from Elymus repens carries a novel locus Fhb.Er-1StL conferring resistance to Fusarium head blight in wheat

Fusarium head blight (FHB) is a globally prevalent wheat disease caused by multiple species within Fusarium genus. P1142-1-2 is a wheat- E. repens partial amphidiploid with high resistance to FHB. However, its detailed genome composition and the genetic information of the chromatin derived from E. repens remains unclear, which limits the transfer and utilization of its potential resistance gene into wheat. Based on GISH and FISH karyotypes analysis, this study confirmed that P1142-1-2 possesses a complete genome of common wheat and seven homologous pairs of chromosomes containing alien chromatin. The GenoBaits®Wheat-St 45K liquid microarray analysis revealed that the alien chromatin contains different St chromatin from chromosomes 1St to 7St of E. repens , respectively. Two FHB-resistant wheat- E. repens derivative lines were identified from the self-progenies of P1142-1-2×Chuannong16 (a cultivar susceptible to FHB) and were characterized as a T1StL·1StL chromosome translocation line and a t1StL telosomic addition line, respectively. A total of 17 molecular markers were developed specific to 1StL and were used to construct a physical map of 1StL. Linkage analysis demonstrated that 1StL confers FHB resistance with a distinct dosage effect. Diagnostic markers analysis excludes the presence of the known alien FHB R genes on 1StL, and it is proposed that 1StL harbors a novel FHB resistance locus, designated as Fhb.Er-1StL , which enriches the wheat FHB resistance gene pool.