Fig 1.
Puccinia striiformis f. sp. tritici (Pst; wheat stripe rust) infection symptoms on several Brachypodium distachyon accessions.
(A) Leaf browning 14 days after inoculation with Pst isolate 08/21. (B) Micrograph of the same leaves cleared and stained with a chitin-binding fluorophore (WGA-FITC) to visualize hyphal growth. Boxed leaf area in (A) corresponds approximately to leaf area in (B). The bars are equal to 10 mm.
Fig 2.
Two major effect loci govern P. striiformis resistance in the ABR6 x Bd21 F4:5 population.
Composite interval mapping using averaged phenotypes of F4:5 families scored 14 days post inoculation with P. striiformis f. sp. tritici (Pst) isolates 08/21 (A), 08/501 (B), and 11/08 (C), and P. striiformis f. sp. hordei (Psh) isolate B01/2 (D). Leaf browning (orange) and pCOL (purple) were averaged across replicates before performing linkage analyses using an additive model (H0:H1). Results were plotted based on normalized permutation thresholds (nLOD), using the threshold of statistical significance based on 1,000 permutations (blue horizontal line). N = 114 F4:5 families.
Fig 3.
Restriction of P. striiformis f. sp. tritici and P. striiformis f. sp. hordei colonization in the ABR6 x Bd21 F4:5 population by Yrr1 and Yrr3.
Phenotype by genotype for the major effect loci Yrr1 and Yrr3 for Pst isolates 08/21 (A), 08/501 (B), and 11/08 (C), and Psh isolate B01/2 (D). pCOL phenotypes for lines homozygous at Yrr1 (marker Bd4_29700796) and Yrr3 (marker Bd2_51527431) show that ABR6 alleles at both loci provide resistance to Pst isolates, whereas only Yrr3 contributes to resistance against Psh isolate B01/2. Error bars represent one standard error. Number of families for the four homozygous groups from left to right: 13, 23, 25, and 16.
Table 1.
Significant QTLs from composite interval mapping of averaged leaf browning and percent colonization phenotypes for P. striiformis isolates in the ABR6 x Bd21 F4:5 population.
Fig 4.
Restriction of P. striiformis f. sp. tritici colonization in Foz1 x Luc1 and Luc1 x Jer1 F2 populations by Yrr1 and Yrr3.
Phenotype by genotype for the major effect loci Yrr1 and Yrr3 in the Foz1 x Luc1 (A) and Luc1 x Jer1 (B) F2 populations. pCOL phenotypes for lines homozygous at Yrr1 (marker Bd4_29128782_60_R) and Yrr3 (markers Bd2_51602833_60_F (A) and Bd2_51552779_60_F (B)) show that Foz1 alleles at both loci provide resistance in the Foz1 x Luc1 F2 population, whereas only Yrr3 contributes to resistance in the Luc1 x Jer1 F2 population. Error bars represent one standard error. Number of individuals for the four homozygous groups from left to right: (A) 11, 15, 10, and 11; (B) 18, 11, 16, and 9.
Table 2.
Significant QTLs from composite interval mapping of leaf browning and percent colonization phenotypes for P. striiformis f. sp. tritici isolate 08/21 in the Foz1 x Luc1 and Luc1 x Jer1 F2 populations.
Table 3.
Analysis of annotated gene models within the maximal two-LOD support intervals of Yrr1 and Yrr3. Numbers represent the number of gene models within each category.
Fig 5.
Canonical resistance genes associated with the Yrr1 and Yrr3 loci.
Annotated nucleotide binding (NB) domain or leucine-rich repeat (LRR) encoding genes from the Bd21 reference sequence are indicated. One-LOD and two-LOD support intervals for pCOL phenotypes were determined with interval mapping. Within boxplots, thick bars denote the peak marker; the box defines the one-LOD support interval, and whiskers delineate the two-LOD support interval. Missing whiskers indicate a shared one-LOD and two-LOD support interval boundary. The solid black box corresponds to the fine-mapped Yrr1 interval (see Gilbert et al.). Gene identifiers for the canonical resistance genes are listed in S5 File. Structural variation and gene expression information can be found in S6 File. AxB = ABR6 x Bd21 F4:5 population; FxL = Foz1 x Luc1 F2 population; LxJ = Luc1 x Jer1 F2 population; 08/21, 08/501, and 11/08 = Pst isolates; B01/2 = Psh isolate.
Table 4.
Pairwise comparison of polymorphic sites (top) and patristic distances of nucleotide substitutions per million sites shown in S9 Fig (bottom) between the different P. striiformis isolates.