Quantitative Trait Loci (QTL) Analysis Reveals Both Broad-Spectrum and Isolate-Specific QTL for Scab Resistance in an Apple Progeny Challenged with Eight Isolates of Venturia inaequalis

The major scab resistance gene Vf, extensively used in apple breeding programs, was recently overcome by the new races 6 and 7 of the fungal pathogen Venturia inaequalis. New, more durable, scab resistance genes are needed in apple breeding programs. F1 progeny derived from the cross between partially resistant apple cv. Discovery and apple hybrid ‘TN10-8’ were inoculated in the greenhouse with eight isolates of V. inaequalis, including isolates able to overcome Vf. One major resistance gene, Vg, and seven quantitative trait loci (QTL) were identified for resistance to these isolates. Three QTL on linkage group (LG)12, LG13, and LG15 were clearly isolate-specific. Another QTL on LG5 was detected with two isolates. Three QTL on LG1, LG2, and LG17 were identified with most isolates tested, but not with every isolate. The QTL on LG2 displayed alleles conferring different specificities. This QTL co-localized with the major scab resistance genes Vr and Vh8, whereas the QTL on LG1 colocalized with Vf. These results contribute to a better understanding of the genetic basis of the V. inaequalis-Malus × domestica interaction.

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Mapping of Quantitative Trait Loci for Scab Resistance in Apple (Malus × Domestica)

10.21203/rs.3.rs-1003617/v1 ◽

2021 ◽

Author(s):

Saba Mir ◽

Aafreen Sakina ◽

Khalid Z. Masoodi ◽

Khalid M. Bhat ◽

Bilal A. Padder ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Quantitative Trait ◽

Venturia Inaequalis ◽

Durable Resistance ◽

Genetic Resistance ◽

In Silico Analysis ◽

Genomic Region ◽

Scab Resistance ◽

Chromosome 2 ◽

Trait Loci

Abstract Scab caused by Venturia inaequalis (Cke.) Wint. is the most important fungal disease of apple. Fungicide application is a widely practiced method of disease control. The use of chemicals is however, cost intensive, tedious and ecologically unsafe. Development of genetic resistance and breeding of resistant cultivars is most reliable and a safest option. One such source of scab resistance happens to be the variety ‘Shireen’, released from SKUASTKashmir. However, till date the nature of resistance and its genetic control has not been characterized. The aim of this research was to elucidate the genetic basis of scab resistance in Shireen. The present study helped us to identify two quantitative trait loci (QTLs) on chromosome 2 and 8 and six potential CDGs for the polygenic resistance in ‘Shireen’. The genomic region corresponding to the mapped QTLs in LG 2 and LG 8 of ‘Shireen’ was examined for candidate genes possibly related to scab resistance using in silico analysis. The QTLs mapped in the genetic background of Shireen are the novel QTLs and may be transferred to desirable genetic backgrounds and provide opportunities for isolation and cloning of genes apart from their utility in order to achieve durable resistance to scab.

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Genetic dissection of partial resistance to race 6 of Venturia inaequalis in apple

Genome ◽

10.1139/g02-127 ◽

2003 ◽

Vol 46 (2) ◽

pp. 224-234 ◽

Cited By ~ 60

Author(s):

C E Durel ◽

L Parisi ◽

F Laurens ◽

W E Van de Weg ◽

R Liebhard ◽

...

Keyword(s):

Resistance Gene ◽

Malus Domestica ◽

Quantitative Trait ◽

Partial Resistance ◽

Venturia Inaequalis ◽

Genetic Dissection ◽

Resistance Breakdown ◽

Trait Locus ◽

New Races ◽

Genomic Regions

Scab, caused by the fungus Venturia inaequalis, is one of the most important diseases of apple (Malus × domestica). The major resistance gene, Vf, has been widely used in apple breeding programs, but two new races of the fungus (races 6 and 7) are able to overcome this gene. A mapped F1 progeny derived from a cross between the cultivars Prima and Fiesta has been inoculated with two monoconidial strains of race 6. These strains originated from sporulating leaves of 'Prima' and a descendant of 'Prima' that were grown in an orchard in northern Germany. 'Prima' carries the Vf resistance gene, whereas 'Fiesta' lacks Vf. A large variation in resistance and (or) susceptibility was observed among the individuals of the progeny. Several quantitative trait loci (QTLs) for resistance were identified that mapped on four genomic regions. One of them was located in the very close vicinity of the Vf resistance gene on linkage group LG-1 of the 'Prima' genetic map. This QTL is isolate specific because it was only detected with one of the two isolates. Two out of the three other genomic regions were identified with both isolates (LG-11 and LG-17). On LG-11, a QTL effect was detected in both parents. The genetic dissection of this QTL indicated a favourable intra-locus interaction between some parental alleles.Key words: Malus × domestica, partial resistance, Venturia inaequalis, resistance breakdown, quantitative trait locus.

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Inheritance and Quantitative Trait Loci Analysis of Resistance Genes to Bruchid and Bean Bug in Mungbean (Vigna radiata L. Wilczek)

Plant Breeding and Biotechnology ◽

10.9787/pbb.2015.3.1.039 ◽

2015 ◽

Vol 3 (1) ◽

pp. 39-46 ◽

Cited By ~ 16

Author(s):

Myon-Gi Hong ◽

Kil-Hyun Kim ◽

Ja-Hwan Ku ◽

Jin-Kyo Jeong ◽

Min-Jung Seo ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Resistance Genes ◽

Quantitative Trait ◽

Vigna Radiata ◽

Trait Loci ◽

Bean Bug

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Quantitative trait loci analysis of seed coat color components for selective breeding in chickpea (Cicer arietinum L.)

Canadian Journal of Plant Science ◽

10.4141/cjps10112 ◽

2011 ◽

Vol 91 (1) ◽

pp. 49-55 ◽

Cited By ~ 11

Author(s):

Shanoor Hossain ◽

Joe Panozzo ◽

Chris Pittock ◽

Rebecca Ford

Keyword(s):

Quantitative Trait Loci ◽

Seed Coat ◽

Quantitative Trait ◽

Selective Breeding ◽

Coat Color ◽

Seed Coat Color ◽

Breeding Programs ◽

Cicer Arietinum L ◽

Trait Loci ◽

Color Components

Hossain, S., Panozzo, J. F., Pittock, C. and Ford, R. 2011. Quantitative trait loci analysis of seed coat color components for selective breeding in chickpea (Cicer arietinumL.). Can. J. Plant Sci. 91: 49–55. Chickpea (Cicer arietinum L.) is an annual grain legume, grown worldwide for human consumption with the potential to attract premium prices in markets such as India, Bangladesh and southern Asia. The ability to accurately select for seed coat color, an important export quality trait, would greatly benefit chickpea breeding programs. In order to determine the major genomic loci governing the color trait, the color components of CIE L* (luminance), CIE a* (red/green color) and CIE b* (blue/yellow color), C* (chroma or saturation of the color) and h° (hue or purity of the color) were mapped, and associated molecular markers were identified. A linkage map was constructed with 80 SSR markers distributed over 10 linkage groups at an average marker density of 2.8 cM. Two major quantitative trait loci (QTL), which accounted for up to 36 and 49% of the genetic variance and several smaller genetic effects were determined to govern the color components. These were consistent across two differing environments. Once validated, the markers that are close to and flanking these QTL and significantly associated with the minor gene effects will be useful in future color selective breeding programs.

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Relationship Between Loci Conferring Downy Mildew and Powdery Mildew Resistance in Melon Assessed by Quantitative Trait Loci Mapping

Phytopathology ◽

10.1094/phyto-95-0556 ◽

2005 ◽

Vol 95 (5) ◽

pp. 556-565 ◽

Cited By ~ 58

Author(s):

L. Perchepied ◽

M. Bardin ◽

C. Dogimont ◽

M. Pitrat

Keyword(s):

Quantitative Trait Loci ◽

Powdery Mildew ◽

Downy Mildew ◽

Resistance Genes ◽

Quantitative Trait ◽

Pseudoperonospora Cubensis ◽

Podosphaera Xanthii ◽

Resistance Qtl ◽

Trait Loci ◽

Artificial Inoculations

Partial resistance to downy mildew (Pseudoperonospora cubensis) and complete resistance to powdery mildew (Podosphaera xanthii races 1, 2, 3, and 5 and Golovinomyces cichoracearum race 1) were studied using a recombinant inbred line population between ‘PI 124112’ (resistant to both diseases) and ‘Védrantais’ (susceptible line). A genetic map of melon was constructed to tag these resistances with DNA markers. Natural and artificial inoculations of Pseudoperonospora cubensis were performed and replicated in several locations. One major quantitative trait loci (QTL), pcXII.1, was consistently detected among the locations and explained between 12 to 38% of the phenotypic variation for Pseudoperonospora cubensis resistance. Eight other Pseudoperonospora cubensis resistance QTL were identified. Artificial inoculations were performed with several strains of four races of Podosphaera xanthii and one race of G. cichoracearum. Two independent major genes, PmV.1 and PmXII.1, were identified and shown to be involved in the simple resistance to powdery mildew. Three digenic epistatic interactions involving four loci were detected for two races of Podosphaera xanthii and one race of G. cichoracearum. Co-localization between PmV.1, resistance genes, and resistance genes homologues was observed. Linkage between the major resistance QTL to Pseudoperonospora cubensis, pcXII.1, and one of the two resistance genes to powdery mildew, PmXII.1, was demonstrated.

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Apple Contains Receptor-like Genes Homologous to the Cladosporium fulvum Resistance Gene Family of Tomato with a Cluster of Genes Cosegregating with Vf Apple Scab Resistance

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.4.508 ◽

2001 ◽

Vol 14 (4) ◽

pp. 508-515 ◽

Cited By ~ 111

Author(s):

Boris A. Vinatzer ◽

Andrea Patocchi ◽

Luca Gianfranceschi ◽

Stefano Tartarini ◽

Hong-Bin Zhang ◽

...

Keyword(s):

Gene Family ◽

Resistance Gene ◽

Resistance Genes ◽

Transmembrane Domain ◽

Venturia Inaequalis ◽

Scab Resistance ◽

Common Disease ◽

Resistance Locus ◽

Cladosporium Fulvum ◽

High Quality

Scab caused by the fungal pathogen Venturia inaequalis is the most common disease of cultivated apple (Malus × domestica Borkh.). Monogenic resistance against scab is found in some small-fruited wild Malus species and has been used in apple breeding for scab resistance. Vf resistance of Malus floribunda 821 is the most widely used scab resistance source. Because breeding a high-quality cultivar in perennial fruit trees takes dozens of years, cloning disease resistance genes and using them in the transformation of high-quality apple varieties would be advantageous. We report the identification of a cluster of receptor-like genes with homology to the Cladosporium fulvum (Cf) resistance gene family of tomato on bacterial artificial chromosome clones derived from the Vf scab resistance locus. Three members of the cluster were sequenced completely. Similar to the Cf gene family of tomato, the deduced amino acid sequences coded by these genes contain an extracellular leucine-rich repeat domain and a transmembrane domain. The transcription of three members of the cluster was determined by reverse transcription-polymerase chain reaction to be constitutive, and the transcription and translation start of one member was verified by 5′ rapid amplification of cDNA ends. We discuss the parallels between Cf resistance of tomato and Vf resistance of apple and the possibility that one of the members of the gene cluster is the Vf gene. Cf homologs from other regions of the apple genome also were identified and are likely to present other scab resistance genes.

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A Genome-Wide Meta-Analysis of Rice Blast Resistance Genes and Quantitative Trait Loci Provides New Insights into Partial and Complete Resistance

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-21-7-0859 ◽

2008 ◽

Vol 21 (7) ◽

pp. 859-868 ◽

Cited By ~ 216

Author(s):

Elsa Ballini ◽

Jean-Benoît Morel ◽

Gaétan Droc ◽

Adam Price ◽

Brigitte Courtois ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Resistance Genes ◽

Quantitative Trait ◽

Rice Blast ◽

Blast Resistance ◽

Durable Resistance ◽

Rice Genome ◽

Blast Disease ◽

Trait Loci ◽

Blast Resistance Genes

The completion of the genome sequences of both rice and Magnaporthe oryzae has strengthened the position of rice blast disease as a model to study plant–pathogen interactions in monocotyledons. Genetic studies of blast resistance in rice were established in Japan as early as 1917. Despite such long-term study, examples of cultivars with durable resistance are rare, partly due to our limited knowledge of resistance mechanisms. A rising number of blast resistance genes and quantitative trait loci (QTL) have been genetically described, and some have been characterized during the last 20 years. Using the rice genome sequence, can we now go a step further toward a better understanding of the genetics of blast resistance by combining all these results? Is such knowledge appropriate and sufficient to improve breeding for durable resistance? A review of bibliographic references identified 85 blast resistance genes and approximately 350 QTL, which we mapped on the rice genome. These data provide a useful update on blast resistance genes as well as new insights to help formulate hypotheses about the molecular function of blast QTL, with special emphasis on QTL for partial resistance. All these data are available from the OrygenesDB database.

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