Abstract
Dasypyrum villosum has been used as a valuable gene resource for disease resistances, yield increase and quality improvement in wheat. A novel wheat-D. villosum alien introgression line CD-3 was generated through hybridization between the common wheat Chinese Spring (CS) and a CS- D. villosum 3V addition line having considerably high stripe rust resistance, which enable the characterization of a potential new stripe rust resistance gene (s) derived from D. villosum. The results of non-denaturing fluorescent in situ hybridization (ND-FISH) showed that CD-3 contained 42 chromosomes, including a 3V chromosome pair, and the absence of both of the 3D chromosomes. PCR-based Landmark Unique Gene (PLUG) molecular marker analysis supported results from the FISH analysis, revealing CD-3 was a wheat-D. villosum 3V (3D) disomic substitution line. Resistant test of stripe rust on 52 plants of F2 generation (CD-3/CS), CD-3, CS and D.villosum have been conducted at seedling stage. 7 plants of F2 generation possessing two 3V chromosomes exhibited high resistance to stripe rust as CD-3 and D.villosum, 10 plants carrying one 3V chromosome and 35 plants without 3V chromosome were susceptive to stripe rust as CS. The result implied the high stripe rust resistance of CD-3 should be controlled by recessive gene(s) originating from D.villosum. To rapidly detect chromosome 3V in the genetic background of wheat, we developed a novel Sequence Characterized Amplified Region (SCAR) marker specific for 3V chromosome based on the sequence of a grain size-related gene DvGS5 in D. villosum, an orthologue of TaGS5 from wheat. The SCAR marker was designated DvGS5-1443, which could successfully amplify a unique 3V-specific fragment in CD-3 and D. villosum, suggesting that this SCAR marker could facilitate targeting the chromosome 3V in the genetic background of wheat for wheat improvement.
Highlights
Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst), is considered one of the most dangerous diseases of wheat (Triticum aestivum L.) worldwide, and in China [1]
Line CD-3 and the sixty plants of CD-3 used for stripe rust test were the F6 progeny derived from hybridization of Chinese Spring (CS) and CS-D. villosum 3V addition line (# 3)
Sequential Non-denaturing fluorescent in situ hybridization (ND-FISH) was conducted on the mitotic spread chromosomes of CD-3 using probes of Oligo-pSc119.2, Oligo-pTa535, Oligo-pHv62-1 and Oligo-(GAA)7 (Fig 1A–1C)
Summary
Stripe (or yellow) rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst), is considered one of the most dangerous diseases of wheat (Triticum aestivum L.) worldwide, and in China [1]. The development of disease-resistant wheat cultivars has been suggested to be the most effective, economical, and environmentally friendly strategy to control stripe rust [3,4]. Numerous Yr (yellow rust) genes have been identified, and they have been officially designated as Yr1- Yr78 [5]. Concerning the coevolution of plants and pathogens, many of the extensively used Yr genes, such as Yr9 and Yr26, did not confer adequate resistance to newly emerging Pst strains [6]. There is an urgent need for exploring and identifying novel and effective resistance genes against newly emerged Pst strains. A substantial body of evidence supports that wild relatives of wheat constitute a valuable gene pool for disease resistance in wheat[8,9,10]. Chromosome arm 1RS of rye harboring powdery resistant genes (Pm8 and Pm17) and rust resistance genes (Sr31, Lr26 and Yr9) [11,12], and 6VS arm of Dasypyrum villosum carrying powdery mildew resistant gene (Pm21) [13] are prevalent in wheat commercial cultivars
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