Identification of powdery mildew resistance QTL in Fragaria x ananassa

AbstractThe obligate biotrophic fungus Podosphaera aphanis is the causative agent of powdery mildew on cultivated strawberry (Fragaria x ananassa). Genotypes from two bi-parental mapping populations ‘Emily’ x ‘Fenella’ and ‘Redgauntlet’ x ‘Hapil’ were phenotyped for powdery mildew disease severity in a series of field trials. Here we report multiple QTL associated with resistance to powdery mildew, identified in ten phenotyping events conducted across different years and locations. Seven QTL show a level of stable resistance across multiple phenotyping events however many other QTL were represented in a single phenotyping event and therefore must be considered transient. One of the identified QTL was closely linked to an associated resistance gene across the wider germplasm. Furthermore, a preliminary association analysis identified a novel conserved locus for further investigation. Our data suggests that resistance is highly complex and that multiple additive sources of quantitative resistance to powdery mildew exist across strawberry germplasm. Implementation of the reported markers in marker-assisted breeding or genomic selection would lead to improved powdery mildew resistant strawberry cultivars, particularly where the studied parents, progeny and close pedigree material are included in breeding germplasm.Key MessagePowdery mildew resistance in two strawberry mapping populations is controlled by both stable and transient novel QTL of moderate effect. Some transferability of QTL across wider germplasm was observed.

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Genetic mapping of three alleles at the Pm3 locus conferring powdery mildew resistance in common wheat (Triticum aestivum L.)

Genome ◽

10.1139/g04-079 ◽

2004 ◽

Vol 47 (6) ◽

pp. 1130-1136 ◽

Cited By ~ 25

Author(s):

Xiu-Qiang Huang ◽

Sai L.K Hsam ◽

Volker Mohler ◽

Marion S Röder ◽

Friedrich J Zeller

Keyword(s):

Triticum Aestivum ◽

Powdery Mildew ◽

Genetic Mapping ◽

Microsatellite Markers ◽

Microsatellite Marker ◽

Powdery Mildew Resistance ◽

Triticum Aestivum L ◽

Mildew Resistance ◽

Marker Loci ◽

Mapping Populations

A set of differential isolates of Blumeria graminis f.sp. tritici was used to identify 10 alleles at the Pm3 locus on the short arm of chromosome 1A. Three F3 populations were used to map Pm3h in Abessi, Pm3i in line N324, and Pm3j alleles in GUS 122 relative to microsatellite markers. In total, 13 marker loci were mapped on chromosome 1AS and 1 marker on 1AL. The order of marker loci in the 3 mapping populations is consistent with previously published maps. All 3 alleles were mapped in the distal region of chromosome 1AS. The present study indicated that microsatellite markers are an ideal marker system for comparative mapping of alleles at the same gene locus in different mapping populations. The linkage distances of the closest microsatellite marker, Xgwm905–1A, to Pm3h, Pm3i, and Pm3j were 3.7 cM, 7.2 cM, and 1.2 cM, respectively. The microsatellite marker Xgwm905–1A cannot be used to distinguish between Pm3 alleles. The development of specific markers for individual Pm3 alleles is discussed on the basis of the recently cloned Pm3b allele.Key words: genetic mapping, marker-assisted selection, microsatellite markers, Pm3 locus, powdery mildew resistance, Triticum aestivum.

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Basal Host Resistance of Barley to Powdery Mildew: Connecting Quantitative Trait Loci and Candidate Genes

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-1-0091 ◽

2010 ◽

Vol 23 (1) ◽

pp. 91-102 ◽

Cited By ~ 71

Author(s):

Reza Aghnoum ◽

Thierry C. Marcel ◽

Annika Johrde ◽

Nicola Pecchioni ◽

Patrick Schweizer ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Powdery Mildew ◽

Candidate Genes ◽

Quantitative Trait ◽

Powdery Mildew Resistance ◽

Adult Plant ◽

Basal Resistance ◽

Mildew Resistance ◽

Trait Loci ◽

Mapping Populations

The basal resistance of barley to powdery mildew (Blumeria graminis f. sp. hordei) is a quantitatively inherited trait that is based on nonhypersensitive mechanisms of defense. A functional genomic approach indicates that many plant candidate genes are involved in the defense against formation of fungal haustoria. It is not known which of these candidate genes have allelic variation that contributes to the natural variation in powdery mildew resistance, because many of them may be highly conserved within the barley species and may act downstream of the basal resistance reaction. Twenty-two expressed sequence tag or cDNA clone sequences that are likely to play a role in the barley–Blumeria interaction based on transcriptional profiling, gene silencing, or overexpression data, as well as mlo, Ror1, and Ror2, were mapped and considered candidate genes for contribution to basal resistance. We mapped the quantitative trait loci (QTL) for powdery mildew resistance in six mapping populations of barley at seedling and adult plant stages and developed an improved high-density integrated genetic map containing 6,990 markers for comparing QTL and candidate gene positions over mapping populations. We mapped 12 QTL at seedling stage and 13 QTL at adult plant stage, of which four were in common between the two developmental stages. Six of the candidate genes showed coincidence in their map positions with the QTL identified for basal resistance to powdery mildew. This co-localization justifies giving priority to those six candidate genes to validate them as being responsible for the phenotypic effects of the QTL for basal resistance.

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Identification and Expression Analysis of Fragaria Vesca MLO Genes Involved in Interaction with Powdery Mildew (Podosphaera Aphanis)

Journal of Advances in Plant Biology ◽

10.14302/issn.2638-4469.japb-17-1838 ◽

2017 ◽

Vol 1 (1) ◽

pp. 40-54 ◽

Cited By ~ 1

Author(s):

Shridhar Jambagi ◽

Jim M. Dunwell ◽

Jim M. Dunwell

Keyword(s):

Powdery Mildew ◽

Powdery Mildew Resistance ◽

Resistance Locus ◽

Fragaria Vesca ◽

Rna Seq ◽

Mildew Resistance ◽

Yield And Quality ◽

Powdery Mildew Infection ◽

Strawberry Cultivars ◽

Diploid Strawberry

Strawberry powdery mildew, caused by Podosphaeraaphanis is a major fungal disease that affects strawberry yield and quality. In the model plant species Arabidopsis and the crop plants barley, tomato and pea, the Mildew resistance locus O (MLO) proteins have been found to be required for powdery mildew susceptibility. The present study, based on the sequence of a wild plum (Prunus americana) MLO protein, identified 16 MLO genes within the genome of woodland strawberry, Fragaria vesca and examined their expression pattern in response to powdery mildew infection in three diploid strawberry cultivars. Phylogenetic analysis showed that the FvMLO genes can be classified into six clades. Four FvMLO genes were grouped into clade III, which comprises MLO genes from Arabidopsis, tomato and grapevine that mediate powdery mildew susceptibility. A RNA-seq analysis of two diploid strawberry cultivars, F. vescassp. vesca accession Hawaii 4 (HW) and F. vesca f. semperflorens line “Yellow Wonder 5AF7” (YW) at 1 d (1 DAI) and 8 d (8 DAI) after infection showed the expression of 12 out of the 16 FvMLO genes. The comparison of Fragments Per Kilobase of transcript per Million mapped reads (FPKM values) detected by RNA-seq and expression values of qRT-PCR for FvMLO genes showed substantial agreement. The FvMLO3 gene, which was grouped in clade III and orthologous to the Arabidopsis,tomato and grapevine genes, was highly expressed in YW compared to other FvMLO genes across varieties. The results showed that FvMLO genes can be used as potential candidates to engineer powdery mildew resistance in strawberry based on MLO suppression or genome editing.

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Powdery Mildew Resistance of the Lithuanian Winter Wheat Breeding Material

Proceedings of the Latvian Academy of Sciences Section B Natural Exact and Applied Sciences ◽

10.2478/v10046-009-0013-x ◽

2009 ◽

Vol 63 (1-2) ◽

pp. 37-44

Author(s):

Žilvinas Liatukas ◽

Vytautas Ruzgas

Keyword(s):

Powdery Mildew ◽

Winter Wheat ◽

Powdery Mildew Resistance ◽

Quantitative Resistance ◽

Wheat Breeding ◽

Resistance Level ◽

Mildew Resistance ◽

Breeding Material ◽

Progress Curve ◽

Wheat Lines

Powdery Mildew Resistance of the Lithuanian Winter Wheat Breeding Material At the Lithuanian Institute of Agriculture, during 2004-2006, resistance to powdery mildew of approximately 1,500 winter wheat lines was assessed in check and competitive trial nurseries. Our experimental evidence showed that there were no genotypes with effective resistance singlegenes among the lines tested. Effective powdery mildew resistance from start to end of vegetation season depended on the quantitative resistance level. The most resistant lines were evaluated with a score of 2 and area under the disease progress curve (AUDPC) values ranging between 1.0-5.4. The most susceptible genotypes from the collection nurseries had score 8-9 and AUDPC values ranging between 1350-2220. The correlations between maximal disease severity and AUDPC values were strong (r = 0.79-0.92). Genotypes with AUDPC values up to 10 represented 93 lines or 7% in the check trial nursery and 22 lines or 9% in the competitive trial nursery. Lines evaluated with a score 4-5 and AUDPC value 100-300 dominated in 2004. In the next year the dominant genotypes had resistance scores 3-4 and AUDPC value 50-200. The highest powdery mildew resistance (score 2 and AUDPC value 1.0) was identified for the lines Maverich/Victo, Flair/Lut.9392, Strumok/Lut.9321, Zentos/Lut.97-6, Strumok/Lut.9313, Dirigent/Cortez in 2006.

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High resolution mapping of a Hordeum bulbosum-derived powdery mildew resistance locus in barley using distinct homologous introgression lines

10.1101/867960 ◽

2019 ◽

Author(s):

Parastoo Hoseinzadeh ◽

Brigitte Ruge-Wehling ◽

Patrick Schweizer ◽

Nils Stein ◽

Hélène Pidon

Keyword(s):

Powdery Mildew ◽

Resistance Gene ◽

Gene Pool ◽

Powdery Mildew Resistance ◽

Introgression Lines ◽

Large Set ◽

Hordeum Bulbosum ◽

Mildew Resistance ◽

The Impact ◽

Mapping Populations

AbstractPowdery mildew caused by Blumeria graminis f.sp. hordei (Bgh) is one of the main foliar diseases in barley (Hordeum vulgare L.; Hv). Naturally occurring resistance genes used in barley breeding are a cost effective and environmentally sustainable strategy to minimize the impact of pathogens, however, the primary gene pool of H. vulgare contains limited diversity owing to recent domestication bottlenecks. To ensure durable resistance against this pathogen, more genes are required that could be unraveled by investigation of secondary barley gene-pool. A large set of Hordeum bulbosum (Hb) introgression lines (ILs) harboring a diverse set of desirable resistance traits have been developed and are being routinely used as source of novel diversity in gene mapping studies. Nevertheless, this strategy is often compromised by a lack of recombination between the introgressed fragment and the orthologous chromosome of the barley genome. In this study, we fine-mapped a Hb gene conferring resistance to barley powdery mildew. The initial genotyping of two Hb ILs mapping populations with differently sized 2HS introgressions revealed severely reduced interspecific recombination in the region of the introgressed segment, preventing precise localization of the gene. To overcome this difficulty, we developed an alternative strategy, exploiting intraspecific recombination by crossing two Hv/Hb ILs with collinear Hb introgressions, one of which carries a powdery mildew resistance gene, while the other doesn’t. The intraspecific recombination rate in the Hb-introgressed fragment of 2HS was approximately 20 times higher than it was in the initial simple ILs mapping populations. Using high-throughput genotyping-by-sequencing (GBS), we allocated the resistance gene to a 1.4 Mb interval, based on an estimate using the Hv genome as reference, in populations of only 103 and 146 individuals respectively, similar to what is expected at this locus in barley. The most likely candidate resistance gene within this interval encodes a legume-type lectin-receptor-like protein (LecRLP). Like other LecRLPs that have been implicated in resistance, this gene could be a good candidate for Hb resistance. The reported strategy can be applied as a general strategic approach for identifying genes underlying traits of interest in crop wild relatives.

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Evaluation of Resistance to Powdery Mildew in Triticale Seedlings and Adult Plants

Plant Disease ◽

10.1094/pdis-02-12-0161-re ◽

2013 ◽

Vol 97 (3) ◽

pp. 410-417 ◽

Cited By ~ 8

Author(s):

V. Troch ◽

K. Audenaert ◽

A. Vanheule ◽

B. Bekaert ◽

M. Höfte ◽

...

Keyword(s):

Powdery Mildew ◽

Plant Growth ◽

Resistance Genes ◽

Powdery Mildew Resistance ◽

Quantitative Resistance ◽

Durable Resistance ◽

Adult Plant ◽

Growth Stages ◽

Mildew Resistance ◽

Plant Growth Stages

Triticale (×Triticosecale) is the intergeneric hybrid between the female parent wheat and the male parent rye. With the expansion of the triticale growing area, powdery mildew emerged on this new host and has become a significant disease on triticale. Recent research demonstrated that this “new” powdery mildew on triticale has emerged through a host range expansion of powdery mildew of wheat. Moreover, this expansion occurred recently and multiple times at different locations in Europe. An effective and environmentally sensitive approach to controlling powdery mildew involves breeding crop plants for resistance. The main goal of this study was to identify the presence of powdery mildew resistance in commercial triticale cultivars. First, the avirulence (AVR) genes and gene complexity carried by this new powdery mildew population on triticale were characterized. Virulence was identified for all the resistance genes evaluated in the present study, and virulence frequencies higher than 50% were recorded on the genes Pm3f, Pm5b, Pm6, Pm7, Pm8, and Pm17. Using molecular markers, the presence of resistance genes Pm3f and Pm17 was identified in certain triticale cultivars. The triticale cultivars were also evaluated for the presence of quantitative resistance at adult plant growth stages in a 2-year field experiment. Despite the high disease pressure, cultivars highly resistant at the adult-plant growth stages were identified. Because ‘Grenado’ also showed effective race-specific resistance, this cultivar could be of high value for breeding for durable resistance to powdery mildew. Altogether, this study reveals valuable information on the presence of powdery mildew resistance in commercial triticale cultivars, which can be used in breeding programs in triticale. Additionally, this study underscores the need to broaden the base of powdery mildew resistance in triticale through introgression and deployment of new sources of mildew resistance, including quantitative resistance.

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