Powdery Mildew Research Articles

AAC Planet field pea

AAC Planet is a semi-leafless and powdery mildew (caused by Erysiphe pisi Syd.) resistant field pea ( Pisum sativum L.) variety developed at Agriculture and Agri-Food Canada, Lacombe Research and Development Centre, Lacombe, Alberta, Canada. It has high yielding potential, late maturity, tall plant height with good lodging resistance, medium seed size, round seed shape, and low seed coat breakage. It has maturity of 100 days, and thousand-seed weight of 221 g with seed protein content of 24.6%. AAC Planet has a lodging score of 3.2 on the scale of 1–9. It is moderately susceptible to mycosphaerella blight (caused by Mycosphaerella pinodes) and fusarium root rot (caused by Fusarium avenaceum and F. solani).

Structural variation in the pangenome of wild and domesticated barley.

Pangenomes are collections of annotated genome sequences of multiple individuals of a species1. The structural variants uncovered by these datasets are a major asset to genetic analysis in crop plants2. Here we report a pangenome of barley comprising long-read sequence assemblies of 76 wild and domesticated genomes and short-read sequence data of 1,315 genotypes. An expanded catalogue of sequence variation in the crop includes structurally complex loci that are rich in gene copy number variation. To demonstrate the utility of the pangenome, we focus on four loci involved in disease resistance, plant architecture, nutrient release and trichome development. Novel allelic variation at a powdery mildew resistance locus and population-specific copy number gains in a regulator of vegetative branching were found. Expansion of a family of starch-cleaving enzymes in elite malting barleys was linked to shifts in enzymatic activity in micro-malting trials. Deletion of an enhancer motif is likely to change the developmental trajectory of the hairy appendages on barley grains. Our findings indicate that allelic diversity at structurally complex loci may have helped crop plantsto adapt to new selective regimes in agricultural ecosystems.

Genome‐wide association study for powdery mildew resistance in CIMMYT's spring wheat germplasm

AbstractPowdery mildew (PM), caused by Blumeria graminis f. sp. tritici (Bgt), is a foliar disease of wheat (Triticum aestivum) that adversely affects both grain yield and quality. Growing resistant cultivars offers an effective and environmentally sustainable solution to managing PM. However, relying on the same genetic source of resistance can lead to resistance breakdown as Bgt isolates rapidly evolve. To mitigate this, identifying novel resistance sources is crucial. In this study, 225 diverse wheat genotypes were evaluated at adult plant stage in disease nurseries over the three crop seasons (2018/2019, 2019/2020 and 2020/2021). Using disease and genotyping data from 12,160 single‐nucleotide polymorphism (SNP) markers, a genome‐wide association study (GWAS) was conducted to identify novel resistance loci. We identified 22 marker loci significantly (at p < 0.005) associated with PM resistance, distributed across 14 wheat chromosomes (1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 4A, 4B, 5D, 6A, 7A and 7B). Of these, seven loci overlap with previously identified regions, while the remaining 15 loci represent novel regions reported for the first time in this study. The identified SNP markers have significant potential for wheat breeding programmes, as they can accelerate the development of PM‐resistant cultivars through marker‐assisted selection.

Unveiling resistance expression profile to powdery mildew in wheat via Bulked Segregant RNA-Seq.

Developing wheat cultivars with durable resistance to powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is crucial for sustainable agriculture. The wheat genotype MYC exhibited high resistance to the Bgt isolate E09 at the seedling stage. Genetic analysis identified a recessive gene, temporarily named PmMYC, responsible for this resistance. Understanding the molecular mechanisms underlying this resistance is essential for advancing breeding programs. Bulked Segregant RNA-Seq revealed numerous alternative splicing events generated following Bgt infection, suggesting powdery mildew may disrupt alternative splicing and affect immune responses. Gene Ontology (GO) analysis indicated significant enrichment of differentially expressed genes in "response to stimuli" and "immune system processes", implying their roles in disease defense. BSR-Seq analysis identified two high-confidence candidate regions for PmMYC on chromosome 2B, spanning 40,451,950 - 102,426,703bp and 421,707,046-449,840,516bp. Within these intervals, 740 genes were identified, with nonsynonymous mutations in 46 genes in the parents and bulks. Real-time PCR showed distinct expression profiles in four genes in resistant MYC compared to susceptible Yannong 21. KEGG and COG analyses of differentially expressed genes in candidate intervals revealed enrichment in immune processes related to plant-pathogen interactions, confirming that PmMYC initiated a broad immune response to prevent Bgt invasion. The study identified key genetic intervals and genes involved in the resistance of wheat genotype MYC to Bgt. The identified genes, particularly those with altered expression profiles, could serve as valuable targets for breeding programs aimed at developing wheat cultivars with durable resistance to powdery mildew. These findings enhanced our understanding of plant-pathogen interactions and provided a foundation for future genetic and functional studies.

Signs, Causes, Fighting Apple Diseases

Numerous diseases often damage apples in home orchards each year. These include fly agaric and sooty mold, summer blight, black rot, powdery mildew, and cedar apple rust. This article discusses the signs, causes, progression, treatment, and preventive measures for several apple tree diseases. Some infections attack the tree roots in the fall, but symptoms do not appear until the following spring, when the tree can no longer absorb enough water and nutrients to continue growing. Disease control in apple orchards is difficult due to the lack of effective chemical treatments. Preventive measures can help control these diseases.

Cover crops lower the dispersal of grapevine foliar pathogens from the ground and contribute to early-season disease management

Currently, fungicides are widely used to control grapevine foliar diseases. This study explored the possibility of decreasing the use of fungicides to control these diseases using cover crops in the inter-row of vineyards. In small-scale experiments, we found that cover crops (namely horseradish Armoracia rusticana) were able to (i) reduce the numbers of airborne conidia of Botrytis cinerea (originating from an inoculum source above the soil) escaping the cover canopy by >85% with respect to the base soil and (ii) reduce the number of raindrops impacting the soil by 46%–74%, depending on the cover crop height and rain-originated splash droplets that escaped from the ground by 75%–95%, which reduced splash-borne inoculum. In two organic vineyards, for 2 years, fall- (mixture of Lolium perenne, Onobrychis viciifolia, and Trifolium repens) or spring-sown (a mixture of Vicia sativa and Sinapis sp.) cover crops could significantly delay (by 14–30 days) and reduce (till >90%) the development of downy and powdery mildew epidemics. This effect was more evident in plots untreated with fungicides than in treated plots. Cover crops also delayed the onset of epidemics depending on the type of cover crop and disease. Cover crops did not negatively affect grape yield and quality. Overall, the results showed that the introduction of cover crops in vineyard management can significantly contribute to disease control by lowering the load from ground to grapevine canopies of pathogen inocula, delaying disease onset, and reducing diseases severity during the season.

AAC McMurphy field pea

AAC McMurphy is a semi-leafless, yellow cotyledonary field pea ( Pisum sativum L.) cultivar developed at Agriculture and Agri-Food Canada Lacombe Research and Development Centre, Lacombe, Alberta, Canada. It has a maturity of 90 days, one-thousand-seed weight of 246 g, and a lodging score of 2.9 on the scale of 1–9. The seed crude protein content of AAC McMurphy is 24.2%. AAC McMurphy is resistant to powdery mildew (caused by Erysiphe pisi) and moderately susceptible to mycosphaerella blight (caused by Mycosphaerella pinodes) and fusarium root rot (caused by Fusarium avenaceum).

A newly identified photosystem II Subunit P gene TaPsbP4A-1 in Triticeae species negatively regulates wheat powdery mildew resistance

The photosystem II (PSII) Subunit P (PsbP) protein is a component of its oxygen-evolving complex, which can oxidize water to produce oxygen using light energy and is critical to the core components and stability of PSII. Using the whole-genome information, the PsbP genes of 10 plant species were comprehensively identified. The expression patterns of wheat PsbPs under Blumeria graminis f. sp. tritici (Bgt) infection were assessed using qRT-PCR, and the functions of TaPsbPs in wheat powdery mildew resistance were studied using barley stripe mosaic virus-induced gene silencing. In total, 122 PsbP genes were divided into 8 classes with similar gene structures. No tandem repeat events were identified in wheat PsbP, suggesting that the PsbP genes in common wheat were donated by its diploid progenitor species. The expression levels of TaPsbP2A-1, TaPsbP3A-1, TaPsbP4A-1, TaPsbP4A-2, and TaPsbP7A-2 were induced by Bgt. The silencing of TaPsbP4A-1 increased the resistance of common wheat ‘Bainong AK58’ to Bgt. This study provides valuable information for functional and evolutionary research on the PsbP gene family.

First Report of Powdery Mildew Caused by Golovinomyces ambrosiae on Symphyotrichum subulatum in China.

Symphyotrichum subulatum (Michx.) G. L. Nesom (syn. Aster subulatus), an annual herb in the Asteraceae family, is native to North America. Nowadays, it has become an invasive weed in several provinces of China, including Jiangsu, Zhejiang, and Sichuan (Li and Xie, 2002). Despite being invasive, this species holds significance in Chinese medicine, where it is used for the external treatment of eczema and swollen sore poison (Hu, 2020). In June 2023, symptoms of powdery mildew were observed in S. subulatum populations in Deyang and Nanchong, Sichuan Province, China. About 32.73% among 55 surveyed S. subulatum plants showed signs of infection. Symptoms initially appeared as small, scattered white powdery patches on the leaves, which enlarged and coalesced over time. Subsequently, hyphal growth forming extensive conidia covered up to 90% of the leaf area on both surfaces (Fig. S1A, B), and the infected leaves withered and fell off (Fig. S1A). A specimen was archived at China West Normal University (SsPM-ZL). Conidiophores were cylindrical and erect, 66.4 to 183.2 µm (avg. 108.2±40.8 μm) in length (n=30) (Fig. S1C). Conidia, produced singly, were ellipsoid-ovoid to nearly cylindrical, measuring 29.5 to 36.7 μm in length (avg. 32.9±2.6 μm) and 16.0 to 19.9 μm in width (avg. 17.4±1.3 μm), lacking distinct fibrosin bodies (n=30) (Fig. S1D). Under a scanning electron microscope, turgid conidia displayed reticulate wrinkles on the surface, with gentle contractions or bulges at both poles (Fig. S1E, F). Based on these characteristics, the powdery mildew fungus was consistent with the genus Golovinomyces (Bradshaw et al. 2022a). To confirm the identity of the causal fungus of specimen (SsPM-ZL), the calmodulin (CAM), RNA polymerase II subunit (RPB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutamine synthetase (GS), and the internal transcribed spacer (ITS) were amplified using PMCAMF/R, PMRPB2F/R, PMGAPDH1/3R, PMGSF/R, and PM5/ITS4 primers (Bradshaw et al. 2022b), and deposited in GenBank (CAM: OR761878; RPB2: OR761881; GAPDH: OR761879; GS: OR761880; ITS: OR758452). BLAST analysis showed 99 to 100% identity with the sequences of Golovinomyces ambrosiae (FH00941234) for CAM (ON101658, 99.65%), RPB2 (ON119165, 100%), GS (ON075690, 99.78%), and ITS (ON073876, 99.47%). Phylogenetic analysis was performed in MEGAX with maximum likelihood method (Kumar et al. 2016) and clustered SsPM-ZL into the G. ambrosiae clade with a 100% bootstrap support value based on the concatenated sequences of CAM, RPB2, GAPDH, GS and ITS (Fig. S2). Combining morphological and phylogenetic analyses, SsPM-ZL was identified as Golovinomyces ambrosiae. To evaluate pathogenicity, leaves of 3 healthy potted S. subulatum plants (3 leaves per plant) were inoculated by gently pressing them with diseased leaves, while 3 non-contact plants were used as control. Plants in two groups were incubated in separate greenhouses maintained at 27±1°C, with a photoperiod of 14 hours and a relative humidity of 80%. After 7 days, the inoculated plants exhibited symptoms of powdery mildew (Fig. S1H, J), while the control plants remained asymptomatic (Fig. S1G, I). Morphological characteristics of the artificially induced powdery mildew were consistent with those on naturally infected plants. Powdery mildew caused by G. ambrosiae has been reported affecting Helianthus tuberosus (Huang et al. 2017) and Bidens pilosa (Mukhtar et al. 2022) in China. To our knowledge, this is the first report of powdery mildew caused by G. ambrosiae on S. subulatum in China. Our finding will provide the fundamental knowledge for future powdery mildew diagnosis and the development of potential control strategies.

Quantitative Trait Loci Mapping for Powdery Mildew Resistance in Wheat Genetic Population

Background/Objectives: Powdery mildew is a prevalent wheat disease that affects yield and quality. The characterization and fine mapping of genes associated with powdery mildew resistance can benefit marker-assisted breeding. Methods: In this study, quantitative trait loci (QTL) associated with powdery mildew were mapped using a high-density 35K DArT genetic linkage map developed from a population of double haploid lines (DHs) created by crossing “Jinmai 33 (a highly resistance line) with Yannong 19 (a highly susceptible line)”. Results: Three stable QTLs for powdery mildew were identified on chromosomes 1B, 2B, and 6A combined with the composite interval graphing method and multiple interval mapping, explaining phenotypic variations (PVE) that range from 4.98% to 13.25%. Notably, Qpm.sxn-1B and Qpm.sxn-2B were identified across three environments, with the PVE ranging from 9.37% to 13.25% and from 4.98% to 5.23%, respectively. The synergistic effects of these QTLs were contributed by the parental line “Jinmai 33”. Qpm.sxn-1B was the major stable QTL, and Qpm.sxn-2B was close to Pm51. Furthermore, Qpm.sxn-6A was identified in two environments, accounting for PVE values of 7.13% and 7.65%, respectively, with the resistance effects originating from the male parent. Remarkably, this locus has not been reported previously, indicating that Qpm.sxn-6A represents a newly dis-covered QTL governing powdery mildew genes. Conclusions: Five molecular markers available for mark-er-assisted selection were selected for tracking Qpm.sxn-1B and Qpm.sxn-2B in the program. The identification of this novel newly discovered QTL and markers reported in this study will be useful for marker-assisted selection of powdery mildew resistance.

Identification of powdery mildew resistance quantitative trait loci in melon and development of resistant near-isogenic lines through marker-assisted backcrossing

BackgroundMelon (Cucumis melo L.), an important cucurbit crop, faces production limitations due to powdery mildew (PM). Developing resistant varieties offers a sustainable, genetics-based alternative to chemical treatments. Therefore, identifying PM resistance quantitative trait loci (QTL) and creating trait-associated markers are essential for efficient melon PM resistance improvement through marker-assisted backcrossing (MABC).ResultsThree F2 populations, A6, B2, and C4, were generated for QTL mapping of PM resistance. Major QTL were identified on chromosome 2 in A6, chromosome 5 in B2, and chromosomes 5 and 12 in C4. A series of TaqMan® assays targeting regions on chromosomes 2, 5, and 12 were developed and validated for foreground and recombinant selection, complemented by the double digest restriction-site associated DNA genotyping system to evaluate the recurrent parent genome recovery. Three MABC programs using resistant donor parents from A6 and C4 crossed with elite susceptible recurrent parents with green and orange fruit flesh were implemented. After two to three cycles of MABC, individual QTL was successfully introgressed into elite genetic backgrounds, giving six PM resistance lines in each green- and orange-fleshed background. PM inoculation on the twelve near-isogenic lines confirmed their resistance to PM.ConclusionsWe have identified major PM resistance QTL for melon on chromosomes 2, 5, and 12 and have introgressed individual QTL to elite genetic backgrounds using MABC in three and a half years. This study demonstrates the power of combining high-throughput genotyping with breeding efforts and showcases the efficiency of molecular breeding.

Proteome Profiling of Cucurbita pepo Phyllosphere After Infection by Podosphaera xanthii and Application of Reynoutria sachalinensis Extract

Podosphaera xanthii is the main causal agent of powdery mildew (PM) disease for Cucurbita pepo. Disease control is attained principally by applications of chemical fungicides, along with parallel use of tolerant crop varieties and alternate application of elicitors to control development of disease resistance. To get insight into C. pepo molecular responses to P. xanthii infection and elicitor treatment we studied the proteomic profile differences at the phyllosphere of a zucchini cultivar susceptible to PM, at the onset of P. xanthii (PX) infection and after application of Reynoutria sachalinensis (RS) plant extract, respectively, using a nano-LC-HRMS/MS, Q-Exactive-Orbitrap approach. Analysis of peptide sequences regarding four treatment groups (Control; PX; RS; and RSPX (PX-infected priorly treated with RS)) resulted in 2070 CuGenDB annotations. Three comparisons (treatments vs. Control) encompassed most of the Differentially Expressed Proteins (DEPs). In these three comparisons, KEGG and Gene Ontology functional analyses highlighted unique differentially enriched pathways—some of which included highly expressed proteins—in PX-related (proteasome, pentose phosphate pathway, and carbon fixation), RS-related (biosynthesis of secondary metabolites, flavonoids, and starch and sucrose metabolism), and RSPX-related (pyruvate metabolism and polycomb repressive complex) comparisons, respectively, suggesting distinct mechanisms of early plant responses modulated by PX and RS. Furthermore, in four out of six comparisons the thiamine metabolism pathway was found to be enriched, suggesting a pivotal role in PX-induced responses.

Effects of Protected Cultivation on Agronomic, Yield, and Quality Traits of Yard-Long Bean (Vigna unguiculata ssp. unguiculata cv.-gr. sesquipedalis)

Protected cultivation is the sustainable approach to horticultural crop production under adverse climates. In this study, the performance of yard-long beans under three protected cultivations, including single-span polyhouse (SSP), five-span polyhouse (FSP), and insect-proof net house (IPN), is examined and compared to open field cultivation. The above protected cultivation can extend the harvest period of pods by 6–10 days, improve their quality, and increase yield by 15.6% to 25.1%, reducing the incidence and severity of thrips and Cercospora leaf spot, rust, and powdery mildew. Among them, yard-long beans grown in SSP are longer and straighter in shape and have the lowest incidence and severity of pests and diseases and the highest levels of total polyphenols, total sugar, soluble protein, starch, and fiber. This indicates that protected cultivation has broad application in the production of yard-long beans. Through full subset regression analysis (FSRA), we report here that the yield and of yard-long bean occurrences of pests and diseases were highly impacted by climatic factors, especially UV radiation intensity and air temperature. These results have considerable implications for improving pod yield and quality and green prevention and control of pests and diseases through optimizing facility structure and fertilizer management.

Phylogeny and taxonomy of the genera of Erysiphaceae, part 6: Erysiphe (the "Microsphaera lineage" part 2).

This is the sixth contribution in a series devoted to the phylogeny and taxonomy of powdery mildews. This part includes our third treatment of the species of the genus Erysiphe. It continues the previous contribution on the phylogenetic-taxonomic assessment of the species belonging to the "Microsphaera lineage." Since this is a large lineage, we have split the treatment of the "Microsphaera lineage" into two parts. Phylogenetic trees based on rDNA are supplemented by sequences of additional markers (CAM, GAPDH, GS, RPB2, and TUB). The "Erysiphe trifoliorum complex" is a challenging group that belongs to the "Microsphaera lineage." Adequate clarification of this complex will be possible when additional worldwide multilocus sequence analyses are performed. The new species Erysiphe acetosae, E. acmisponis, E. lathyrina, E. salmoniana, and E. santalicola are described, and the new combinations E. biuncinata and E. pavoniae are introduced. Specimens of several species have been sequenced for the first time, particularly North American species, such as Erysiphe caryae, E. ceanothi, E. juglandis-nigrae, and E. ravenelii. Erysiphe syringae is lectotypified and 15 species names are epitypified in order to provide ex-epitype reference sequences. For other species, non-ex-type reference sequences are proposed for phylogenetic-taxonomic purposes. Ex-type sequences for Erysiphe baptisiicola, E. sesbaniae, Microsphaera sydowiana, M. umbilici, and Oidium pavoniae have been retrieved.

Research Progress on the Genetic and Molecular Mechanisms of Cucumber (Cucumis sativus L.) Powdery Mildew Resistance

As a common fungal disease, powdery mildew (PM) is one of the main diseases that harm the growth and development of cucumbers. Understanding the types of pathogenic fungus and analysis of the genetic and molecular mechanisms of cucumber resistance to PM at the molecular level are important when breeding disease-resistant varieties. The present review summarizes the hazards, prevention, and control of PM, and it discusses resistance inheritance rules, molecular markers, quantitative trait locus (QTL) mapping, gene cloning, omics, and gene editing technology, providing research insights on cucumber breeding varieties resistant to PM.

Effectiveness of plant extracts against Alternaria leaf blight (Alternaria alternata) infecting tomato

Tomato (Lycopersicon esculentum Mill.) is one of the most remunerative and widely grown vegetables in the world. This crop is affected by major fungal pathogens (viz., early blight, late blight, wilt, collar rot, damping off and powdery mildew), among them early blight (Alternaria alternata) is considered as most important one. Among the phyto-extracts tested, the majority were found effective in inhibiting the radial growth of test fungus and highest inhibition was in neem, garlic and turmeric extracts at 10 % concentration which recorded 80.86, 79.34 and 75.24 % inhibition, respectively.

Effectiveness of systemic fungicides against tomato early blight (Alternaria alternata)

Tomato (Lycopersicon esculentum Mill.) is one of the most remunerative and widely grown vegetables in the world. This crop is affected by major fungal pathogens (viz., early blight, late blight, wilt, collar rot, damping off and powdery mildew), among them early blight (Alternaria alternata) is considered as most important one. Among the fungicide tested, the majority were found effective in inhibiting the radial growth of test fungus and highest inhibition was observed in propiconazole 25 EC at 250 and 500 ppm concentration; difenoconazole 25 EC and tebuconazole 25.9 EC at 500 ppm concentration which were equally effective and completely inhibited the mycelial growth and proved significantly superior over rest of the treatments.

Population structure and markers analysis associated with powdery mildew resistance in pumpkin, Cucurbita pepo L

Pumpkin (Cucurbita pepo L.) is an economically important vegetable and summer crop. The seeds have high nutritional value due to their edible oil and protein content with a high medicinal value. Pumpkin is attacked by several fungal diseases; one of which is powdery mildew (PM) caused by Podosphaera xanthii race-0. PM causes severe disease on pumpkin leading to major yield losses globally. In this study, we analyzed the genetic diversity and population structure of fourteen local pumpkin cultivars, all under Cucurbita pepo L. based on dominance in the region using 15 Inter-Simple-Sequence-Repeats-(ISSR) primer-pairs in association with resistance against PM as well as regulating the expression of three resistant marker genes i.e. SGT1, bHLH and PSK via qRT-PCR at three stages with 10 days' interval post-inoculation-stages-(SPI) with the powdery mildew agent, P. xanthii race-0. The results showed that ISSR markers demonstrated 13 primers out of 15 primers generated 169 distinct amplified bands, out of which 143 bands showed polymorphism. The mean polymorphism information content (PIC), marker index (MI), effective-number of alleles (I), expected heterozygosity (H), and Nei's gene diversity parameters were 0.354, 3.344, 0.334, 0.205 and 0.200, respectively. According to PIC, MI, I, H, and Nei indices evaluation, ISSR10 primer had the best performance in genetic diversity of the related pumpkin population. NTSYS pc 2.02e software and several similarity coefficients (r = 0.964), placed the related genotypes into five distinct groups. Of which, ‘Maragheh1′ and ‘Shahreza’ as resistant ones with 9.4 % and 6.1 % disease severity (DS), and ‘Gorgan’, ‘Urmia1′ and 3 and ‘Maragheh3’ with 79.6–84.8 % DS, as susceptible ones into two distinct groups, respectively. Further, the marker genes SGT1, bHLH and PSK expression level changes showed that the effect of variable factors including different genotypes (susceptible and resistant), disease-causing fungus, SPI, and the mutual effect of these factors is significant with the highest increase in resistant genotypes. Considering the relative compatibility in the classification of pumpkin genotypes in the dendrograms of DS and ISSR markers, it can be expected that increasing the number of markers in evaluating the genetic diversity of these genotypes makes it possible to differentiate pumpkin genotypes resistant and susceptible to PM disease based on the degree of disease resistance. The markers associated with resistance are recommended for use in marker assisted breeding.

The effect of powdery mildew on the cell structure and cell wall composition of red clover

The effect of powdery mildew on the cell structure and cell wall composition of red clover

Development and Characterization of Two Wheat-Rye Introgression Lines with Resistance to Stripe Rust and Powdery Mildew.

Rye (Secale cereale L.) genes, which contribute to the tertiary gene pool of wheat, include multiple disease resistance genes useful for the genetic improvement of wheat. Introgression lines are the most valuable materials for wheat breeding because of their small alien segments and limited or lack of linkage drag. In the present study, wheat-rye derivative lines SN21627-2 and SN21627-6 were produced via distant hybridization. A genomic in situ hybridization analysis revealed that SN21627-2 and SN21627-6 lack alien segments, while a multi-color fluorescence in situ hybridization analysis detected structural changes in both introgression lines. At the seedling and adult plant stages, SN21627-2 and SN21627-6 were highly resistant to stripe rust and powdery mildew. Primers for 86 PCR-based landmark unique gene markers and 345 rye-specific SLAF markers were used to amplify SN21627-2 and SN21627-6 genomic DNA. Eight markers specific to rye chromosome 2R were detected in both introgression lines, implying these lines carry chromosome 2R segments with genes conferring stripe rust and powdery mildew resistance. Therefore, SN21627-2 and SN21627-6 are resistant to more than one major wheat disease, making them promising bridging parents for breeding disease-resistant wheat lines.