Identification and Molecular Mapping of a Gummy Stem Blight Resistance Gene in Wild Watermelon (Citrullus amarus) Germplasm PI 189225

Gummy stem blight (GSB), caused by Stagonosporopsis cucurbitacearum (syn. Didymella bryoniae), is a destructive foliar disease of watermelon in areas with hot and humid climates. The wild watermelon germplasm PI 189225 is a known source of resistance to GSB. The identification and use of molecular markers linked to resistance genes in the wild-type germplasm will speed up the introgression of GSB resistance into new watermelon varieties. An F2 segregating population was obtained from a cross between the resistant wild watermelon genotype PI 189225 and the susceptible genotype K3. The F2-derived F3 families were inoculated with a single isolate of S. cucurbitacearum (JS002) from Jiangsu Academy of Agricultural Sciences. The results of the genetic analysis demonstrated that GSB resistance in PI 189225 was controlled by a major quantitative trait locus (QTL), temporarily designated Qgsb8.1. Based on the results of bulk sergeant analysis and sequencing, one associated region spanning 5.7 Mb (10,358,659 to 16,101,517) on chromosome 8 was identified as responsible for the resistance to GSB using the Δ(single-nucleotide polymorphism [SNP]-index) method. The result of a QTL linkage analysis with Kompetitive allele-specific PCR (KASP) SNP markers further mapped the GSB resistance locus between the SNP markers KASP_JS9383 and KASP_JS9168 in a region of 571.27 kb on chromosome 8. According to the watermelon gene annotation database, the region contains approximately 19 annotated genes and, of these 19 genes, 2 are disease resistance gene analogs: Cla001017 (coiled-coil nucleotide-binding site leucine-rich repeat resistance protein) and Cla001019 (pathogenesis related). Reverse-transcription quantitative PCR demonstrated that the expression of the two genes changed following S. cucurbitacearum infection, suggesting that they play important roles in GSB resistance in watermelon. This result will facilitate fine mapping and cloning of the Qgsb8.1 locus, and the linked markers will further provide a useful tool for marker-assisted selection of this locus in watermelon breeding programs.

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QTL Mapping for Gummy Stem Blight Resistance in Watermelon (Citrullus spp.)

Plants ◽

10.3390/plants10030500 ◽

2021 ◽

Vol 10 (3) ◽

pp. 500

Author(s):

Eun Su Lee ◽

Do-Sun Kim ◽

Sang Gyu Kim ◽

Yun-Chan Huh ◽

Chang-Gi Back ◽

...

Keyword(s):

Chromosome 8 ◽

Chromosome 6 ◽

Potential Candidate ◽

Stem Blight ◽

Gummy Stem Blight ◽

F2 Population ◽

Leaf Lesion ◽

Phenotypic Variations ◽

A Minor ◽

Selection Of

Watermelon (Citrulluslanatus) is an economically important fruit crop worldwide. Gummy stem blight (GSB) is one of the most damaging diseases encountered during watermelon cultivation. In the present study, we identified quantitative trait loci (QTLs) associated with GSB resistance in an F2 population derived from a cross between maternal-susceptible line ‘920533’ (C. lanatus) and the paternal-resistant line ‘PI 189225’ (C. amarus). The resistance of 178 F2 plants was assessed by two different evaluation methods, including leaf lesion (LL) and stem blight (SB). To analyze the QTLs associated with GSB resistance, a linkage map was constructed covering a total genetic distance of 1070.2 cM. QTL analysis detected three QTLs associated with GSB resistance on chromosome 8 and 6. Among them, two QTLs, qLL8.1 and qSB8.1 on chromosome 8 identified as major QTLs, explaining 10.5 and 10.0% of the phenotypic variations localizing at same area and sharing the same top markers for both LL and SB traits, respectively. A minor QTL, qSB6.1, explains 9.7% of phenotypic variations detected on chromosome 6 only for the SB trait. High-throughput markers were developed and validated for the selection of resistant QTLs using watermelon accessions, and commercial cultivars. Four potential candidate genes were predicted associated with GSB resistance based on the physical location of flanking markers on chromosome 8. These findings will be helpful for the development of watermelon cultivars resistant to GSB.

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The Sbm1 locus conferring resistance to Soil-borne cereal mosaic virus maps to a gene-rich region on 5DL in wheat

Genome ◽

10.1139/g06-064 ◽

2006 ◽

Vol 49 (9) ◽

pp. 1140-1148 ◽

Cited By ~ 27

Author(s):

C. Bass ◽

R. Hendley ◽

M.J. Adams ◽

K.E. Hammond-Kosack ◽

K. Kanyuka

Keyword(s):

Mosaic Virus ◽

Resistance Gene ◽

Cultural Practices ◽

Mosaic Disease ◽

Disease Resistance Gene ◽

Resistance Locus ◽

Rich Region ◽

Resistant Cultivars ◽

Germplasm Screening ◽

Gene Rich Region

A mosaic disease caused by Soil-borne cereal mosaic virus (SBCMV) is becoming increasingly important, particularly in winter wheat in Europe. As there are currently no effective cultural practices or practical environmentally friendly chemicals for disease control, host plant resistance is an important objective in breeding programs. However, development of resistant cultivars is slow owing to difficulties in germplasm screening for resistance. Therefore, there is a need to identify molecular markers linked to SBCMV-resistance gene(s), so that quick and accurate laboratory-based marker-assisted selection rather than prolonged field-based screens for resistance can be used in developing resistant cultivars. We previously demonstrated that resistance to SBCMV in Triticum aestivum ‘Cadenza’ is controlled by a single locus. In this work, we used AFLP and microsatellite technology to map this resistance locus, with the proposed name Sbm1, to the distal end of chromosome 5DL. Interestingly, several expressed disease-resistance gene analogues also map to this gene-rich region on 5DL. Closely linked (~17 cM interval) markers, BARC110 and WMC765, RRES01 and BARC144, that flank Sbm1 will be very useful in breeding for selection of germplasm carrying Sbm1.

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Epistatic Interaction Effect Between Chromosome 1BL (Yr29) and A Novel Locus on 2AL Facilitating Resistance to Stripe Rust in Chinese Wheat Changwu 357-9

10.21203/rs.3.rs-1069419/v1 ◽

2021 ◽

Author(s):

Shuo Huang ◽

Yibo Zhang ◽

Hui Ren ◽

Xiang Li ◽

Xin Zhang ◽

...

Keyword(s):

Resistance Gene ◽

Stripe Rust ◽

Epistatic Interaction ◽

Rust Resistance ◽

Yellow Rust ◽

Snp Array ◽

Snp Markers ◽

Stripe Rust Resistance ◽

Disease Resistance Gene ◽

Wheat Cultivars

Abstract Stripe rust (yellow rust) is a serious disease of bread wheat ( Triticum aestivum L.) worldwide. Genetic resistance is considered the most economical, effective and environmentally friendly method to control the disease. The current study focused on characterizing the components of stripe rust resistance and understanding the interactions in Changwu 357-9 (CW357-9)/Avocet S RIL population. A genetic linkage map constructed using a new GenoBaits Wheat 16K Panel and the 660K SNP array had 5,104 polymorphic SNP markers spanning 3,533.11 cM. Four stable QTL were detected on chromosome arms 1BL, 2AL, 3DS, and 6BS across all environments in Chngwu357-9. The most effective QTL Q YrCW357-1BL was Yr29 and the 6BS QTL was identified as Yr78 . The novel QTL on 2AL with moderate effect showed significant epistatic interaction with Yr29 . The QTL on 3DL should be same as QYrsn.nwafu-3DL and enriches the overall stripe rust resistance gene pool for breeding. Polymorphisms of flanking AQP markers AX-110020417 (for QYrCW357-1BL ), AX-110020417 (for QYrCW357 -2AL ), AX-109466386 (for QYrCW357 -3DL ), and AX-109995005 (for QYrCW357 -6BS ), were evaluated in a diversity panel including 225 wheat cultivars and breeding lines. The results suggested that these high-throughput markers could be used to introduce QYrCW357-1BL ( Yr29 ), QYrCW357-2AL , QYrCW357 -3DL , and QYrCW357 -6BS into commercial wheat cultivars. Combinations of these genes with other APR QTL should lead to higher levels of stripe rust resistance along with the beneficial effects of multi-disease resistance gene Yr29 on improving resistance to other diseases.

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