scholarly journals 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

2021 ◽  
Author(s):  
Laure PERCHEPIED ◽  
Elisabeth CHEVREAU ◽  
Elisa RAVON ◽  
Sylvain GAILLARD ◽  
Sandra PELLETIER ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Molecular Mechanisms ◽  
Systemic Acquired Resistance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Defense Responses ◽  
Scab Resistance ◽  
European Pear ◽  
Intergeneric Transfer ◽  
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.

scholarly journals 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 ◽  
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.

scholarly journals Phenotypic and transcriptomic analyses reveal major differences between apple and pear scab nonhost resistance

2021 ◽  
Author(s):  
Emilie VERGNE ◽  
Elisabeth CHEVREAU ◽  
Elisa RAVON ◽  
Sylvain GAILLARD ◽  
Sandra PELLETIER ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Venturia Inaequalis ◽  
Stomatal Closure ◽  
Phenylpropanoid Pathway ◽  
Differentially Expressed ◽  
Scab Resistance ◽  
Nonhost Resistance ◽  
Type I ◽  
European Pear ◽  
Pear Scab

Background: Nonhost resistance is the outcome of most plant/pathogen interactions, but it has rarely been described in Rosaceous fruit species. Apple (Malus x domestica Borkh.) is a nonhost for Venturia pyrina, the scab species attacking European pear (Pyrus communis L.). Reciprocally, P. communis is a nonhost for Venturia inaequalis, the scab species attacking apple. The major objective of our study was to compare the scab nonhost resistance in apple and in European pear, at the phenotypic and transcriptomic levels. Results: Macro- and microscopic observations after reciprocal scab inoculations indicated that, after a similar germination step, nonhost apple/V. pyrina interaction remained nearly symptomless, whereas hypersensitive reactions were observed during nonhost pear/V. inaequalis interaction. Comparative transcriptomic analyses of apple and pear nonhost interactions with V. pyrina and V. inaequalis, respectively, revealed considerable differences. Very few differentially expressed genes were detected during apple/V. pyrina interaction, which is consistent with a symptomless type I nonhost resistance. On the contrary, numerous genes were differentially expressed during pear/V. inaequalis interaction, as expected in a type II nonhost resistance involving visible hypersensitive reaction. Pre-invasive defense, such as stomatal closure, was detected, as well as several post-invasive defense mechanisms (apoplastic reactive oxygen species accumulation, phytoalexin production and alterations of the epidermis composition). In addition, a comparative analysis between pear scab host and nonhost interactions indicated that, although specificities were observed, two major defense lines were shared in these resistances: cell wall and cuticle modifications and phenylpropanoid pathway induction. Conclusion: This first deciphering of the molecular mechanisms underlying a nonhost scab resistance in pear offers new possibilities for the genetic engineering of sustainable scab resistance in this species.

scholarly journals A Molecular Marker Linked to a Scab Resistance Gene (Vf) in Apple

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 619a-619
Author(s):  
Hong Y. Yang ◽  
Schuyler S. Korban ◽  
Jutta Kruger ◽  
Hanna Schmidt
Keyword(s):  
Resistance Gene ◽  
Venturia Inaequalis ◽  
Dominant Gene ◽  
Apple Scab ◽  
Scab Resistance ◽  
Polymorphism Analysis ◽  
Recurrent Parent ◽  
Specific Primers ◽  
Apple Cultivars ◽  
Donor Parent

Apple scab, caused by Venturia inaequalis (Cke.) Wint., is the most serious disease of apple trees. Resistance to V. inaequalis, derived from the small-fruited species Malus floribunda 821, is determined by a major dominant gene Vf. Our major objective is to identify RAPD markers linked to the Vf gene. The approach in this paper is based on the introgression of the Vf gene from M. floribunda into commercial cultivars. Almost 200 random sequence decamer-primers have been used to screen a pair of bulked samples and the donor parent M. floribunda clone 821 for markers linked to the Vf gene conferring resistance to apple scab. A single primer has been identified which generated a PCR fragment, OPK16/1300, from the donor parent M. floribunda clone 821 and the scab-resistant selections/cultivars bulk, but not from the scab-susceptible recurrent parent bulk. Co-segregation analysis using a segregating apple progeny and polymorphism analysis of individual scab-resistant Coop selections/cultivars have confirmed that this marker is linked to the scab-resistance gene Vf. OPK16/1300 has since been cloned and sequenced. Sequence-specific primers of 25 oligonucleotides based on the marker have been synthesized and used to screen further M. floribunda clone 821, scab-susceptible apple cultivars, scab-resistant apple cultivars, and scab-resistant Coop selections. The sequence-specific primers have identified polymorphisms of OPK16/1300 based on the presence or absence of a single band.

scholarly journals TheVenturiaApple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Gopaljee Jha ◽  
Karnika Thakur ◽  
Priyanka Thakur
Keyword(s):  
Plant Pathogen ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Resistance Breeding ◽  
Defense Responses ◽  
Scab Resistance ◽  
Plant Defense Responses ◽  
Polygenic Resistance ◽  
Breeding Programs ◽  
Plant Pathogen Interactions

Venturia inaequalisis the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.

scholarly journals Virulence Characterization of Venturia inaequalis Reference Isolates on the Differential Set of Malus Hosts

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 370-375 ◽  
Author(s):  
Valérie Caffier ◽  
Andrea Patocchi ◽  
Pascale Expert ◽  
Marie-Noëlle Bellanger ◽  
Charles-Eric Durel ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Reference Set ◽  
Major Resistance Gene ◽  
Differential Hosts ◽  
Major Resistance Genes

A set of differential hosts has recently been identified for 17 apple scab resistance genes in an updated system for defining gene-for-gene (GfG) relationships in the Venturia inaequalis-Malus pathosystem. However, a set of reference isolates characterized for their complementary avirulence alleles is not yet available. In this paper, we report on improving the set of differential hosts for h(7) and propose the apple genotype LPG3-29 as carrying the single major resistance gene Rvi7. We characterized a reference set of 23 V. inaequalis isolates on 14 differential apple hosts carrying major resistance genes under controlled conditions. We identified isolates that were virulent on at least one of the following defined resistance gene hosts: h(1), h(2), h(3), h(4), h(5), h(6), h(7), h(8), h(9), h(10), and h(13). Sixteen different virulence patterns were observed. In general, the isolates carried one to three virulences, but some of them were more complex, with up to six virulences. This set of well-characterized isolates will be helpful for the identification of additional apple scab resistance genes in apple germplasm and the characterization of new GfG relationships to help improve our understanding of the host-pathogen interactions in the V. inaequalis-Malus pathosystem.

scholarly journals Breakdown of the Scab Resistance Gene Vf in Apple Leads to a Founder Effect in Populations of the Fungal Pathogen Venturia inaequalis

2004 ◽  
Vol 94 (4) ◽  
pp. 364-369 ◽  
Author(s):  
Fabien Guérin ◽  
Bruno Le Cam
Keyword(s):  
Resistance Gene ◽  
Founder Effect ◽  
Allelic Variation ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
Scab Resistance ◽  
Vf Gene ◽  
Major Resistance Gene ◽  
High Level

The recent breakdown of Vf, a major resistance gene to apple scab, provided an opportunity to analyze a population genetic process within the matching virulent subpopulation of the fungus Venturia inaequalis. We utilized the amplified fragment length polymorphism technique and allelic variation at four microsatellite loci to assess genetic structure of 133 isolates of V. inaequalis from a single commercial apple orchard sampled from one cultivar carrying the Vf gene (Judeline) and three cultivars devoid of the Vf gene. Both analyses indicated a strong decrease of the genetic diversity among isolates from the Vf cultivar compared with the high level of diversity among isolates from the three other cultivars. This leads to a high genetic differentiation between virVf and avrVf groups (FST > 0.17). Analyses of the genetic distance between AFLP patterns based on the Jaccard index indicate that all virVf isolates could be assigned to a single clonal lineage. These results lead us to conclude that the clonal structure of the population isolated from the Vf cultivar is an example of a founder effect in response to a resistance gene breakdown and it is likely that this event occurred in the orchard during the sampling year.

scholarly journals A Randomly Amplified Polymorphic DNA (RAPD) Marker Tightly Linked to the Scab-resistance Gene Vf in Apple

1997 ◽  
Vol 122 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Hong Y. Yang ◽  
Schuyler S. Korban ◽  
Jutta Krüger ◽  
Hanna Schmidt
Keyword(s):  
Resistance Gene ◽  
Venturia Inaequalis ◽  
Rapd Marker ◽  
Apple Scab ◽  
Scab Resistance ◽  
Polymorphism Analysis ◽  
Recurrent Parent ◽  
Specific Primers ◽  
Apple Cultivars ◽  
Donor Parent

Almost 200 random sequence decamer primers were used to screen a pair of bulked samples of apple (Malus ×domestica Borkh.) DNA and that of the donor parent Malus floribunda Sieb. clone 821 for molecular markers linked to the Vf gene conferring resistance to apple scab [Venturia inaequalis (Cke.) Wint.]. Identified was a single primer that generated a polymerase chain-reaction (PCR) fragment, OPAR4/1400, from the donor parent M. floribunda clone 821 and the scab-resistant selections/cultivars bulk, but not from the scab-susceptible recurrent-parent bulk. Cosegregation analysis using a segregating apple progeny and polymorphism analysis of individual scab-resistant selections/cultivars confirmed that this marker was linked to the scab-resistance gene Vf OPAR4/1400 was then cloned and sequenced. Sequence-specific primers of 25 oligonucleotides based on the marker were developed and used to screen further M. floribunda clone 821, scab-susceptible apple cultivars, scab-resistant apple cultivars, and scab-resistant Purdue, Rutgers, and Univ. of Illinois apple breeding program selections. The sequence-specific primers identified polymorphisms of OPAR4/1400 based on the presence or absence of a single band. This molecular marker is at a distance of about 3.6 cM from the Vf gene.

Mapping of the apple scab-resistance gene Vb

Genome ◽  
2006 ◽  
Vol 49 (10) ◽  
pp. 1238-1245 ◽  
Author(s):  
N. Erdin ◽  
S. Tartarini ◽  
G.A.L. Broggini ◽  
F. Gennari ◽  
S. Sansavini ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Linkage Group ◽  
Resistance Gene ◽  
Ssr Markers ◽  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Fast Method ◽  
A Genome

Apple scab, caused by the fungus Venturia inaequalis , is the major production constraint in temperate zones with humid springs. Normally, its control relies on frequent and regular fungicide applications. Because this control strategy has come under increasing criticism, major efforts are being directed toward the breeding of scab-resistant apple cultivars. Modern apple breeding programs include the use of molecular markers, making it possible to combine several different scab-resistance genes in 1 apple cultivar (pyramiding) and to speed up the breeding process. The apple scab-resistance gene Vb is derived from the Siberian crab apple ‘Hansen’s baccata #2’, and is 1 of the 6 “historical” major apple scab-resistance genes (Vf, Va, Vr, Vbj, Vm, and Vb). Molecular markers have been published for all these genes, except Vr. In testcross experiments conducted in the 1960s, it was reported that Vb segregated independently from 3 other major resistance genes, including Vf. Recently, however, Vb and Vf have both been mapped on linkage group 1, a result that contrasts with the findings from former testcross experiments. In this study, simple sequence repeat (SSR) markers were used to identify the precise position of Vb in a cross of ‘Golden Delicious’ (vbvb) and ‘Hansen’s baccata #2’ (Vbvb). A genome scanning approach, a fast method already used to map apple scab-resistance genes Vr2 and Vm, was used, and the Vb locus was identified on linkage group 12, between the SSR markers Hi02d05 and Hi07f01. This finding confirms the independent segregation of Vb from Vf. With the identification of SSR markers linked to Vb, another major apple scab-resistance gene has become available; breeders can use it to develop durable resistant cultivars with several different resistance genes.

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

1998 ◽  
Vol 123 (6) ◽  
pp. 992-996 ◽  
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%.

Sign in / Sign up

Export Citation Format

Share Document