Chitinase activities, scab resistance, mycorrhization rates and biomass of own-rooted and grafted transgenic apple

Background: Scab is the most important fungal disease of apple and pear. Apple (Malus x domestica Borkh.) and European pear (Pyrus communis L.) are genetically related but they are hosts of two different fungal species: Venturia inaequalis for apple and V. pyrina for European pear. The apple/V. inaequalis pathosystem is quite well known, whereas knowledge about the pear/V. pyrina pathosystem is still limited. The aim of our study was to analyse the mode of action of a major resistance gene of apple (Rvi6) in transgenic apple and pear plants interacting with the two scab species (V. inaequalis and V. pyrina), in order to determine the degree of functional transferability between the two pathosystems. Results: Transgenic pear clones constitutively expressing the Rvi6 gene from apple were compared to a scab transgenic apple clone carrying the same construct. After inoculation in greenhouse with V. pyrina, strong defense reactions and very limited sporulation were observed on all transgenic pear clones tested. Microscopic observations revealed frequent aborted conidiophores in the Rvi6 transgenic pear / V. pyrina interaction. The macro- and microscopic observations were very comparable to the Rvi6 apple / V. inaequalis interaction. However, this resistance in pear proved variable according to the strain of V. pyrina, and one of the strains tested overcame the resistance of most of the transgenic pear clones. Comparative transcriptomic analyses of apple and pear resistant interactions with V. inaequalis and V. pyrina, respectively, revealed different cascades of molecular mechanisms downstream of the pathogen recognition by Rvi6 in the two species. Signal transduction was triggered in both species with calcium (and G-proteins in pear) and interconnected hormonal signaling (jasmonic acid in pear, auxins in apple and brassinosteroids in both species), without involvement of salicylic acid. This led to the induction of defense responses such as a remodeling of primary and secondary cell wall, lipids biosynthesis (galactolipids in apple and cutin and cuticular waxes in pear), systemic acquired resistance signal generation (in apple) or perception in distal tissues (in pear), and the biosynthesis of phenylpropanoids (flavonoids in apple but also lignin in pear). Conclusion: This study is the first example of a successful intergeneric transfer of a resistance gene among Rosaceae, with a resistance gene functioning towards another species of pathogen.

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Successful intergeneric transfer of a major apple scab resistance gene (Rvi6) from apple to pear and precise comparison of the downstream molecular mechanisms of this resistance in both species

BMC Genomics ◽

10.1186/s12864-021-08157-1 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

L. Perchepied ◽

E. Chevreau ◽

E. Ravon ◽

S. Gaillard ◽

S. Pelletier ◽

...

Keyword(s):

Resistance Gene ◽

Molecular Mechanisms ◽

Systemic Acquired Resistance ◽

Venturia Inaequalis ◽

Apple Scab ◽

Defense Responses ◽

Scab Resistance ◽

European Pear ◽

Intergeneric Transfer ◽

Transgenic Apple

Abstract Background Scab is the most important fungal disease of apple and pear. Apple (Malus x domestica Borkh.) and European pear (Pyrus communis L.) are genetically related but they are hosts of two different fungal species: Venturia inaequalis for apple and V. pyrina for European pear. The apple/V. inaequalis pathosystem is quite well known, whereas knowledge about the pear/V. pyrina pathosystem is still limited. The aim of our study was to analyse the mode of action of a major resistance gene of apple (Rvi6) in transgenic apple and pear plants interacting with the two scab species (V. inaequalis and V. pyrina), in order to determine the degree of functional transferability between the two pathosystems. Results Transgenic pear clones constitutively expressing the Rvi6 gene from apple were compared to a scab transgenic apple clone carrying the same construct. After inoculation in greenhouse with V. pyrina, strong defense reactions and very limited sporulation were observed on all transgenic pear clones tested. Microscopic observations revealed frequent aborted conidiophores in the Rvi6 transgenic pear / V. pyrina interaction. The macro- and microscopic observations were very comparable to the Rvi6 apple / V. inaequalis interaction. However, this resistance in pear proved variable according to the strain of V. pyrina, and one of the strains tested overcame the resistance of most of the transgenic pear clones. Comparative transcriptomic analyses of apple and pear resistant interactions with V. inaequalis and V. pyrina, respectively, revealed different cascades of molecular mechanisms downstream of the pathogen recognition by Rvi6 in the two species. Signal transduction was triggered in both species with calcium (and G-proteins in pear) and interconnected hormonal signaling (jasmonic acid in pear, auxins in apple and brassinosteroids in both species), without involvement of salicylic acid. This led to the induction of defense responses such as a remodeling of primary and secondary cell wall, lipids biosynthesis (galactolipids in apple and cutin and cuticular waxes in pear), systemic acquired resistance signal generation (in apple) or perception in distal tissues (in pear), and the biosynthesis of phenylpropanoids (flavonoids in apple but also lignin in pear). Conclusion This study is the first example of a successful intergeneric transfer of a resistance gene among Rosaceae, with a resistance gene functioning towards another species of pathogen.

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The HD‐Zip I transcription factor MdHB7 ‐like confers tolerance to salinity in transgenic apple ( Malus domestica )

Physiologia Plantarum ◽

10.1111/ppl.13330 ◽

2021 ◽

Author(s):

Shuang Zhao ◽

Haibo Wang ◽

Xumei Jia ◽

Hanbing Gao ◽

Ke Mao ◽

...

Keyword(s):

Transcription Factor ◽

Malus Domestica ◽

Tolerance To Salinity ◽

Transgenic Apple

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PHENOTYPIC SELECTION ASSISTED BY MOLECULAR MARKERS FOR SCAB RESISTANCE IN APPLE

Acta Horticulturae ◽

10.17660/actahortic.2009.814.130 ◽

2009 ◽

pp. 771-776

Author(s):

C. Botez ◽

R. Sestras ◽

M. Ardelean ◽

D. Pamfil ◽

B. Patrascu ◽

...

Keyword(s):

Molecular Markers ◽

Phenotypic Selection ◽

Scab Resistance

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The pattern of flavan-3-ols in relation to scab resistance of apple cultivars

Journal of Horticultural Science ◽

10.1080/00221589.1990.11516087 ◽

1990 ◽

Vol 65 (5) ◽

pp. 511-517 ◽

Cited By ~ 45

Author(s):

D. Treutter ◽

W. Feucht

Keyword(s):

Scab Resistance ◽

Apple Cultivars

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Identification of a Novel Genomic Region Associated With Resistance to Fusarium Head Blight in Chinese Winter Wheat

10.21203/rs.3.rs-149839/v1 ◽

2021 ◽

Author(s):

Yunzhe Zhao ◽

Xinying Zhao ◽

Mengqi Ji ◽

Wenqi Fang ◽

Hong Guo ◽

...

Keyword(s):

Winter Wheat ◽

Fusarium Head Blight ◽

Genome Wide Association Study ◽

Wheat Breeding ◽

Scab Resistance ◽

Yield Reduction ◽

Transferase Activity ◽

Head Blight ◽

A Genome ◽

Fhb Resistance

Abstract Background: Fusarium head blight (FHB) is a disease affecting wheat spikes caused by Fusarium species, which leads to cases of severe yield reduction and seed contamination. Therefore, identifying resistance genes from various sources is always of importance to wheat breeders. In this study, a genome-wide association study (GWAS) focusing on FHB using a high-density genetic map constructed with 90K single nucleotide polymorphism (SNP) arrays in a panel of 205 elite winter wheat accessions, was conducted in 3 environments. Results: Sixty-six significant marker–trait associations (MTAs) were identified (P<0.001) on fifteen chromosomes explaining 5.4–11.2% of the phenotypic variation therein. Some important new genomic regions involving FHB resistance were found on chromosomes 2A, 3B, 5B, 6A, and 7B. On chromosome 7B, 6 MTAs at 92 genetic positions were found in 2 environments. Moreover, there were 11 MTAs consistently associated with diseased spikelet rate and diseased rachis rate as pleiotropic effect loci. Eight new candidate genes of FHB resistance were predicated in wheat. Of which, three genes: TraesCS5D01G006700, TraesCS6A02G013600, and TraesCS7B02G370700 on chromosome 5DS, 6AS, and 7BL, respectively, were important in defending against FHB by regulating chitinase activity, calcium ion binding, intramolecular transferase activity, and UDP-glycosyltransferase activity in wheat. In addition, a total of six excellent alleles associated with wheat scab resistance were discovered. Conclusion: These results provide important genes/loci for enhancing FHB resistance in wheat breeding populations by marker-assisted selection.

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Molecular Markers for the Scab Resistance (Vf) Region in Apple

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.123.6.992 ◽

1998 ◽

Vol 123 (6) ◽

pp. 992-996 ◽

Cited By ~ 17

Author(s):

Minou Hemmat ◽

Norman F. Weeden ◽

Herb S. Aldwinckle ◽

Susan K. Brown

Keyword(s):

Rapd Markers ◽

Bulked Segregant Analysis ◽

Venturia Inaequalis ◽

Apple Scab ◽

Scab Resistance ◽

Resistant Plant ◽

Tight Linkage ◽

Test Population ◽

Rate Selection ◽

Selection Of

Bulked segregant analysis was used to identify RAPD markers that display tight linkage to the Vf gene in apple (Malus sp.) that confers resistance to five races of apple scab [Venturia inaequalis (Cke.) Wint.]. We identified several new RAPD markers linked to Vf. The most tightly linked marker in the test population, S52500, was cloned and sequenced. A linkage map of the Vf region was developed using these markers, RAPD markers previously described by other laboratories, and the isozyme locus Pgm-1. An assay was developed for Vf by multiplexing the two markers closely flanking the Vf locus. This assay has a theoretical `escape' value (discarding a resistant plant) of 3% and an error rate (selection of a susceptible plant) of 0.02%.

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Evaluation of Scab Resistance and Effect of Photosynthetic Rates on Fruit Characteristics among Elite Pear Seedlings

Korean Journal of Environmental Agriculture ◽

10.5338/kjea.2013.32.2.117 ◽

2013 ◽

Vol 32 (2) ◽

pp. 117-122 ◽

Cited By ~ 1

Author(s):

Kyung-Ho Won ◽

Sam-Seok Kang ◽

Yoon-Kyeong Kim ◽

Rajametov Sherzod ◽

Kyeong-Ho Lim ◽

...

Keyword(s):

Scab Resistance ◽

Fruit Characteristics ◽

Photosynthetic Rates

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A Novel Pear Scab (Venturia nashicola) Resistance Gene, Rvn3, from Interspecific Hybrid Pear (Pyrus pyrifolia × P. communis)

Plants ◽

10.3390/plants10122632 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2632

Author(s):

Sewon Oh ◽

Hyeondae Han ◽

Daeil Kim

Keyword(s):

Resistance Gene ◽

Resistance Genes ◽

Interspecific Hybrid ◽

Dominant Gene ◽

Apple Scab ◽

Scab Resistance ◽

Hybrid Population ◽

Pyrus Pyrifolia ◽

Pear Scab ◽

Venturia Nashicola

Asian pear scab is a fungal disease caused by Venturia nashicola. The identification of genes conferring scab resistance could facilitate the breeding of disease-resistant cultivars. Therefore, the present study aimed to identify a scab-resistance gene using an interspecific hybrid population ((Pyrus pyrifolia × P. communis) × P. pyrifolia). Artificial inoculation of V. nashicola was carried out for two years. The segregation ratio (1:1) of resistant to susceptible individuals indicated that resistance to V. nashicola was inherited from P. communis and controlled by a single dominant gene. Based on two years phenotypic data with the Kruskal–Wallis test and interval mapping, 12 common markers were significantly associated with scab resistance. A novel scab resistance gene, Rvn3, was mapped in linkage group 6 of the interspecific hybrid pear, and co-linearity between Rvn3 and one of the apple scab resistance genes, Rvi14, was confirmed. Notably, an insertion in pseudo-chromosome 6 of the interspecific hybrid cultivar showed homology with apple scab resistance genes. Hence, the newly discovered Rvn3 was considered an ortholog of the apple scab resistance gene. Since the mapping population used in the present study is a pseudo-BC1 population, pyramiding of multiple resistance genes to pseudo-BC1 could facilitate the breeding of pear cultivars with durable resistance.

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