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1.
2.
Joshi SG Schaart JG Groenwold R Jacobsen E Schouten HJ Krens FA 《Plant molecular biology》2011,75(6):579-591
Apple scab resistance genes, HcrVf1 and HcrVf2, were isolated including their native promoter, coding and terminator sequences. Two fragment lengths (short and long) of
the native gene promoters and the strong apple rubisco gene promoter (PMdRbc) were used for both HcrVf genes to test their effect on expression and phenotype. The scab susceptible cultivar ‘Gala’ was used for plant transformations
and after selection of transformants, they were micrografted onto apple seedling rootstocks for scab disease tests. Apple
transformants were also tested for HcrVf expression by quantitative RT-PCR (qRT-PCR). For HcrVf1 the long native promoter gave significantly higher expression that the short one; in case of HcrVf2 the difference between the two was not significant. The apple rubisco gene promoter proved to give the highest expression
of both HcrVf1 and HcrVf2. The top four expanding leaves were used initially for inoculation with monoconidial isolate EU-B05 which belongs to race
1 of V. inaequalis. Later six other V. inaequalis isolates were used to study the resistance spectra of the individual HcrVf genes. The scab disease assays showed that HcrVf1 did not give resistance against any of the isolates tested regardless of the expression level. The HcrVf2 gene appeared to be the only functional gene for resistance against Vf avirulent isolates of V. inaequalis. HcrVf2 did not provide any resistance to Vf virulent strains, even not in case of overexpression. In conclusion, transformants carrying the apple-derived HcrVf2 gene in a cisgenic as well as in an intragenic configuration were able to reach scab resistance levels comparable to the
Vf resistant control cultivar obtained by classical breeding, cv. ‘Santana’. 相似文献
3.
Valentina Cova Roberta Paris Stella Passerotti Elena Zini Cesare Gessler Ilaria Pertot Nazia Loi Rita Musetti Matteo Komjanc 《Tree Genetics & Genomes》2010,6(3):389-403
The Malus–Venturia inaequalis interaction is the most studied plant–pathogen interaction involving a woody species. Besides the cloning of an apple scab
resistance gene HcrVf2, several sequences have been recently identified that are modulated after pathogen recognition in Vf-resistant genotypes. Among these, there is a putative leucine-rich repeat receptor-like protein kinase from the apple scab-resistant
cv. Florina, named LRPKm1 that is induced after V. inaequalis inoculation and salicylic acid treatment. In this work, the isolation, characterization, and mapping of four new genes belonging
to the LRPKm multigene family are reported. According to their cumulative expression profiles in HcrVf2-transgenic and wild-type apple plants treated with V. inaequalis, LRPKm genes have been divided in two groups. LRPKm1 and LRPKm3, giving a response related to the presence of HcrVf2, are probably involved in the recognition of pathogen-derived signals. LRPKm2 and LRPKm4, with an expression profile unrelated to the HcrVf2 gene, are putatively involved in the plant basal defense. Furthermore, we have localized LRPKm proteins at the cytological
level in the plasma membrane of epidermal cells in resistant genotypes following pathogen challenge, thus confirming software
predictions and molecular results. The possible involvement of LRPKm proteins in apple scab resistance and in the plant basal
defense makes them attractive for a better comprehension of the molecular mechanisms of the signal transduction pathways after
pathogen recognition. 相似文献
4.
Vanblaere T Szankowski I Schaart J Schouten H Flachowsky H Broggini GA Gessler C 《Journal of biotechnology》2011,154(4):304-311
Cisgenesis represents a step toward a new generation of GM crops. The lack of selectable genes (e.g. antibiotic or herbicide resistance) in the final product and the fact that the inserted gene(s) derive from organisms sexually compatible with the target crop should rise less environmental concerns and increase consumer's acceptance. Here we report the generation of a cisgenic apple plant by inserting the endogenous apple scab resistance gene HcrVf2 under the control of its own regulatory sequences into the scab susceptible apple cultivar Gala. A previously developed method based on Agrobacterium-mediated transformation combined with a positive and negative selection system and a chemically inducible recombination machinery allowed the generation of apple cv. Gala carrying the scab resistance gene HcrVf2 under its native regulatory sequences and no foreign genes. Three cisgenic lines were chosen for detailed investigation and were shown to carry a single T-DNA insertion and express the target gene HcrVf2. This is the first report of the generation of a true cisgenic plant. 相似文献
5.
J.M. Soriano S.G. Joshi M. van Kaauwen Y. Noordijk R. Groenwold B. Henken W.E. van de Weg H.J. Schouten 《Tree Genetics & Genomes》2009,5(3):475-482
Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most devastating diseases for the apple growing in temperate zones with humid springs and summers. Breeding
programs around the world have been able to identify several sources of resistance, the Vf from Malus floribunda 821 being the most frequently used. The appearance of two new races of V. inaequalis (races 6 and 7) in several European countries that are able to overcome the resistance of the Vf gene put in evidence the necessity of the combination of different resistance genes in the same genotype (pyramiding). Here,
we report the identification and mapping of a new apple scab resistance gene (Vd3) from the resistant selection “1980-015-25” of the apple breeding program at Plant Research International, The Netherlands.
This selection contains also the Vf gene and the novel V25 gene for apple scab resistance. We mapped Vd3 on linkage group 1, 1 cM to the south of Vf in repulsion phase to it. Based on pedigree analysis and resistance tests, it could be deduced that 1980-015-25 had inherited
Vd3 from the founder “D3.” This gene provides resistance to the highly virulent EU-NL-24 strain of race 7 of V. inaequalis capable of overcoming the resistance from Vf and Vg.
JMS and SGJ contributed equally to this work 相似文献
6.
Silfverberg-Dilworth E Besse S Paris R Belfanti E Tartarini S Sansavini S Patocchi A Gessler C 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,110(6):1119-1126
Apple scab (Venturia inaequalis) is one of the most damaging diseases affecting commercial apple production. Some wild Malus species possess resistance against apple scab. One gene, HcrVf2, from a cluster of three genes derived from the wild apple Malus floribunda clone 821, has recently been shown to confer resistance to apple scab when transferred into a scab-susceptible apple variety. For this proof-of-function experiment, the use of the 35S promoter from Cauliflower mosaic virus was reliable and appropriate. However, in order to reduce the amount of non-plant DNA in genetically modified apple to a minimum, with the aim of increasing genetically modified organism acceptability, these genes would ideally be regulated by their own promoters. In this study, sequences from the promoter region of the three members of the HcrVf gene family were compared. Promoter constructs containing progressive 5 deletions were prepared and used for functional analyses. Qualitative assessment confirmed promoter activity in apple. Quantitative promoter comparison was carried out in tobacco (Nicotiana glutinosa) and led to the identification of several promoter regions with different strengths from a basal level to half the strength of the 35S promoter from Cauliflower mosaic virus. 相似文献
7.
Thalia Vanblaere Henryk Flachowsky Cesare Gessler Giovanni A. L. Broggini 《Plant biotechnology journal》2014,12(1):2-9
Using resistance genes from a crossable donor to obtain cultivars resistant to diseases and the use of such cultivars in production appears an economically and environmentally advantageous approach. In apple, introgression of resistance genes by classical breeding results in new cultivars, while introducing cisgenes by biotechnological methods maintains the original cultivar characteristics. Recently, plants of the popular apple ‘Gala’ were genetically modified by inserting the apple scab resistance gene Rvi6 (formerly HcrVf2) under control of its own regulatory sequences. This gene is derived from the scab‐resistant apple ‘Florina’ (originally from the wild apple accession Malus floribunda 821). The vector used for genetic modification allowed a postselection marker gene elimination to achieve cisgenesis. In this work, three cisgenic lines were analysed to assess copy number, integration site, expression level and resistance to apple scab. For two of these lines, a single insertion was observed and, despite a very low expression of 0.07‐ and 0.002‐fold compared with the natural expression of ‘Florina’, this was sufficient to induce plant reaction and reduce fungal growth by 80% compared with the scab‐susceptible ‘Gala’. Similar results for resistance and expression analysis were obtained also for the third line, although it was impossible to determine the copy number and TDNA integration site–such molecular characterization is requested by the (EC) Regulation No. 1829/2003, but may become unnecessary if cisgenic crops become exempt from GMO regulation. 相似文献
8.
Aide Wang Herb Aldwinckle Philip Forsline Dorrie Main Gennaro Fazio Susan Brown Kenong Xu 《Molecular breeding : new strategies in plant improvement》2012,29(2):379-397
Malus sieversii is a progenitor species of domestic apple M. × domestica. Using population “GMAL 4595” of 188 individuals derived from a cross of Royal Gala × PI 613988 (apple scab resistant, M. sieversii), 287 SSR (simple sequence repeats) loci were mapped. Of these SSRs, 80 are published anchors and 207 are newly developed
EST (expressed sequence tag) contig-based SSRs, representing 1,630 Malus EST accessions in GenBank. Putative gene functions of these EST contigs are diverse, including regulating plant growth, development
and response to environmental stresses. Among the 80 published SSRs, 18 are PI 613988 specific, 38 are common and 24 are Royal
Gala specific. Out of the 207 newly developed EST contig-based SSRs, 79 are PI 613988 specific, 45 are common and 83 are Royal
Gala specific. These results led to the construction of a M. sieversii map (1,387.0 cM) of 180 SSR markers and a Royal Gala map (1,283.4 cM) of 190 SSR markers. Mapping of scab resistance was
independently conducted in two subsets of population “GMAL 4595” that were inoculated with Ventura inaequalis races (1) and (2), respectively. In combination with the two major resistance reactions Chl (chlorotic lesions) and SN (stellate
necrosis) to each race, four subsets of resistance data, i.e., Chl/race (1), SN/race (1), Chl/race (2) and SN/race (2), were
constituted and analyzed, leading to four resistance loci mapped to the linkage group 2 of PI 613988; SNR1 (stellate necrosis resistance to race (1)) and SNR2 are tightly linked in a region of known scab resistance genes, and ChlR1 (Chlorotic lesion resistance to race (1)) and ChlR2 are also linked tightly but in a region without known scab resistance genes. The utility of the two linkage maps, the new
EST contig-based markers and M. sieversii as sources of apple scab resistance are discussed. 相似文献
9.
G. J. King F. H. Alston L. M. Brown E. Chevreau K. M. Evans F. Dunemann J. Janse F. Laurens J. R. Lynn C. Maliepaard A. G. Manganaris P. Roche H. Schmidt S. Tartarini J. Verhaegh R. Vrielink 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(5):699-708
Apple scab, caused by the fungus Venturia inaequalis (Cke.) Wint., is an important disease in commercial apple production. A mapping population of 155 individuals, derived from
a cross between the apple varieties ‘Prima’ (resistant)בFiesta’ (susceptible), was scored for response to the disease in
replicated field and glasshouse trials throughout Europe. Twenty data sets were selected and cluster analysis was used to
form a consensus score for the population fitting a 1 : 1 segregation ratio of resistance:susceptibility. The progeny were
scored with molecular markers. A detailed map covering 54 cM of the ‘Prima’ linkage group containing the Vf gene for scab resistance was constructed using 24 molecular markers linked to the resistance gene. One isoenzyme marker (Pgm-1), six RFLP markers and 17 RAPD markers formed a linkage group with the consensus measure of resistance to scab. Four marker
bridges were established with the corresponding ‘Fiesta’ linkage group with additional markers (one isozyme, one RFLP, three
RAPD and one AFLP). A low chi-square value indicated a good fit of the marker ordering, which was in close agreement with
previously reported linkage positions for some of the markers and Vf. Differences were observed in the ability of different scoring methods to resolve susceptible and resistant classes. The
results obtained for the consensus classification of resistance to scab for the population may suggest the presence of virulent
inocula at some sites, which could overcome the Vf gene for resistance. The consequences of relying on individual scoring occasions for studying Vf scab resistance are discussed in the context of linkage analysis, conventional breeding selection, and marker-assisted selection.
Received: 23 July 1997 / Accepted: 31 October 1997 相似文献
10.
A. Boudichevskaia H. Flachowsky A. Peil C. Fischer F. Dunemann 《Tree Genetics & Genomes》2006,2(4):186-195
A major scab resistance gene initially called Vr1 was identified in the apple cultivar “Regia” derived from the Malus scab resistance source R12740-7A (Russian seedling, RS). A codominant, multiallelic sequence characterized amplified region (SCAR) marker was developed from a random amplified polymorphic DNA marker identified by bulked-segregant analysis. Additional alleles of the AD13 marker locus proved to be informative for the analysis of genetic relationships within Malus including putative relatives of RS. Separate linkage maps were created for the two families derived from crosses with “Regia”. Using phenotypic data from the greenhouse scab tests, the recombination frequency between Vr1 and AD13-SCAR was between 6 and 17%. The Vr1 locus appeared to be closely linked to the Vx [Hemmat et al. J Am Soc Hortic Sci, 127:365–370, 2002], Vr2 [Patocchi et al. Theor Appl Genet, 109:1087–1092, 2004], and the Vh4 gene [Bus et al. Mol Breed, 15:103–116, 2005a]. Our linkage analysis of the molecular markers identified by Hemmat et al. [J Am Soc Hortic Sci, 127:365–370, 2002] for two scab resistance factors from RS (Vr and Vx) indicate that both genes are separated by a large distance on apple linkage group 2 [Boudichevskaia et al. Acta Hortic, 663:171–175, 2004]. This is in agreement with the results of Bus et al., [Mol Breed, 15:103–116, 2005a] who concluded that (1) the RS-derived gene Vh2 is identical to Vr, (2) the RS-derived gene Vh4 is identical to Vx and Vr1, (3) Vh2/Vr and Vh4/Vr1/Vx map on opposite sides of LG 2. One of our main goals was the verification of the Vr1-SCAR within a practical apple-breeding program. The utility of the AD13-SCAR was evident after 2 years under natural scab infection conditions in both families investigated. This is the first report about the confirmation of a molecular marker for a RS resistance factor in a 2-year field experiment. A multiplex polymerase chain reaction assay based on two codominant SCARs for Vf and Vr1 was tested in an apple progeny segregating for both genes. The result of the two-marker approach is discussed with respect to scab races, which are able to overcome the Vf resistance gene. 相似文献
11.
A detailed linkage map around an apple scab resistance gene demonstrates that two disease resistance classes both carry the V
f gene 总被引:4,自引:0,他引:4
S. E. Gardiner H. C. M. Bassett D. A. M. Noiton V. G. Bus M. E. Hofstee A. G. White R. D. Ball R. L. S. Forster E. H. A. Rikkerink 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(4):485-493
A detailed genetic map has been constructed in apple (Malus x domestica Borkh.) in the region of the v
f gene. This gene confers resistance to the apple scab fungus Venturia inaequalis (Cooke) Wint. Linkage data on four RAPD (random amplified polymorphic DNA) markers and the isoenzyme marker PGM-1, previously reported to be linked to the v
f gene, are integrated using two populations segregating for resistance to apple scab. Two new RAPD markers linked to v
f (identified by bulked segregant analysis) and a third marker previously reported as being present in several cultivars containing v
f are also placed on the map. The map around v
f now contains eight genetic markers spread over approximately 28 cM, with markers on both sides of the resistance gene. The study indicates that RAPD markers in the region of crab apple DNA introgressed with resistance are often transportable between apple clones carrying resistance from the same source. Analysis of co-segregation of the resistance classes 3A (weakly resistant) and 3B (weakly susceptible) with the linked set of genetic markers demonstrates that progeny of both classes carry the resistance gene.This work was supported in part by grants from the New Zealand Foundation for Research Science and Technology (FoRST) Programme 94-HRT-07-366 and ENZA New Zealand (International) 相似文献
12.
13.
The Vh2 and Vh4 scab resistance genes in two differential hosts derived from Russian apple R12740-7A map to the same linkage group of apple 总被引:3,自引:0,他引:3
V.G.M. Bus E.H.A. Rikkerink W.E. van de Weg R.L. Rusholme S.E. Gardiner H.C.M. Bassett L.P. Kodde L. Parisi F.N.D. Laurens E.J. Meulenbroek K.M. Plummer 《Molecular breeding : new strategies in plant improvement》2005,15(1):103-116
Russian apple R12740-7A is the designation for an accession grown from seed collected in Russia, which was found to be highly resistant to apple scab. The resistance has historically been attributed to a naturally pyramided complex involving three major genes: one race-nonspecific gene, Vr, conditioning resistance to all known races, plus two race-specific genes. The race-nonspecific gene was identified as an independently segregating gene by Dayton and Williams (1968) and is referred to in this paper as Vr-DW. The first researchers to study the scab resistance gene complex in Russian apple never described the phenotype conditioned by the race-nonspecific gene. Later, Aldwinckle et al. (1976) associated the name Vr with a scab resistance gene conditioning distinctive stellate necrotic reactions, which we refer to as Vr-A in order to distinguish it from Vr-DW. We show that the segregation ratios in progenies from the scab differential hosts 2 and 4 that are derived from Russian apple, crossed with susceptible cultivars were consistent with a single gene conditioning resistance in each host. The genes have been named Vh2 and Vh4, respectively. Resistant segregants from host 2 showed stellate necrotic reactions, while those from host 4 showed hypersensitive reactions. Both the phenotypes and the genetic maps for the genes in the respective hosts were very similar to those of the genes previously named Vr-A and Vx, respectively, in an F1 family of Russian apple. We showed that race 2 of V. inaequalis isolated from host 2 was able to infect resistant descendants of the non-differential accession PRI 442-23 as well as host 2. The descendants of PRI 442-23 were expected to carry the race-nonspecific Vr-DW gene, but in fact carry Vr-A. We conclude that the Vh2 gene in host 2 and Vr-A are the same, and that the Vh4 gene in host 4 and Vx are the same. However, a major finding of this study is that the latter gene mapped to linkage group 2 of apple instead of linkage group 10 as suggested from previous research. With the two race-specific genes from Russian apple defined now, we discuss the nature of the race-nonspecific Vr-DW gene in this accession. We also report the identification of a new scab resistance gene, VT57, from either Golden Delicious or Red Dougherty, which conditions chlorotic resistance reactions and is linked to Vh2. 相似文献
14.
H. Muranty M.-T. Pavoine B. Jaudeau W. Radek G. Doussinault D. Barloy 《Molecular breeding : new strategies in plant improvement》2009,23(3):445-461
Powdery mildew (Blumeria graminis f. sp. tritici) is one of the major diseases of wheat (Triticum aestivum). Adult plant resistance (APR) to powdery mildew is considered more durable than resistance conferred by major race-specific
resistance genes. The objective of the present study was a better understanding of the genetic basis of APR in RE714 by means
of QTL analysis of several resistance scores along the growing season. A population of 160 recombinant inbred lines obtained
from the cross between RE714 and Hardi (susceptible) was assessed for APR under natural infection conditions during 3 years
and a genetic map with whole genome coverage was developed with microsatellite and AFLP markers in this population. Two major
QTL on chromosomes 5D and 6A were detected each year, and 6 minor QTL were detected only in 1 or 2 years. The QTL on chromosome
5D was detected during all the growing season each year and its R
2 value varied between 8.5 and 56.3%, whereas the QTL on chromosome 6A was detected at 1–4 scoring dates in the 3 years, and
its R
2 value varied between 6.1 and 20.5%. The two QTL explained between 24.4 and 52.1% of the phenotypic variance for AUDPC, depending
on the year. The models including QTL and cofactors in the composite interval mapping explained between 29 and 72% of the
variance. The molecular markers linked to the two major QTL could be used in marker-assisted selection for adult plant resistance
to powdery mildew.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
15.
Identification,isolation and characterization of a CC-NBS-LRR candidate disease resistance gene family in grapevine 总被引:2,自引:0,他引:2
Andreas Kortekamp Leocir Welter Sarah Vogt Alexander Knoll Florian Schwander Reinhard Töpfer Eva Zyprian 《Molecular breeding : new strategies in plant improvement》2008,22(3):421-432
16.
Scab resistance in ‘Geneva’ apple is conditioned by a resistance gene cluster with complex genetic control 下载免费PDF全文
Héloïse Bastiaanse Heather C. M. Bassett Christopher Kirk Susan E. Gardiner Cecilia Deng Remmelt Groenworld David Chagné Vincent G. M. Bus 《Molecular Plant Pathology》2016,17(2):159-172
Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most severe diseases of apple worldwide. It is the most studied plant–pathogen interaction involving a woody species using modern genetic, genomic, proteomic and bioinformatic approaches in both species. Although ‘Geneva’ apple was recognized long ago as a potential source of resistance to scab, this resistance has not been characterized previously. Differential interactions between various monoconidial isolates of V. inaequalis and six segregating F1 and F2 populations indicate the presence of at least five loci governing the resistance in ‘Geneva’. The 17 chromosomes of apple were screened using genotyping‐by‐sequencing, as well as single marker mapping, to position loci controlling the V. inaequalis resistance on linkage group 4. Next, we fine mapped a 5‐cM region containing five loci conferring both dominant and recessive scab resistance to the distal end of the linkage group. This region corresponds to 2.2 Mbp (from 20.3 to 22.5 Mbp) on the physical map of ‘Golden Delicious’ containing nine candidate nucleotide‐binding site leucine‐rich repeat (NBS‐LRR) resistance genes. This study increases our understanding of the complex genetic basis of apple scab resistance conferred by ‘Geneva’, as well as the gene‐for‐gene (GfG) relationships between the effector genes in the pathogen and resistance genes in the host. 相似文献
17.
Sibylle Stoeckli Karsten Mody Cesare Gessler Andrea Patocchi Mauro Jermini Silvia Dorn 《Tree Genetics & Genomes》2008,4(4):833-847
The rosy apple aphid (Dysaphis plantaginea), the leaf-curling aphid (Dysaphis cf. devecta) and the green apple aphid (Aphis pomi) are widespread pest insects that reduce growth of leaves, fruits and shoots in apple (Malus × domestica). Aphid control in apple orchards is generally achieved by insecticides, but alternative management options like growing
resistant cultivars are needed for a more sustainable integrated pest management (IPM). A linkage map available for a segregating
F1-cross of the apple cultivars ‘Fiesta’ and ‘Discovery’ was used to investigate the genetic basis of resistance to aphids.
Aphid infestation and plant growth characteristics were repeatedly assessed for the same 160 apple genotypes in three different
environments and 2 consecutive years. We identified amplified fragment length polymorphism (AFLP) markers linked to quantitative
trait loci (QTLs) for resistance to D. plantaginea (‘Fiesta’ linkage group 17, locus 57.7, marker E33M35–0269; heritability: 28.3%), and to D. cf. devecta (‘Fiesta’ linkage group 7, locus 4.5, marker E32M39–0195; heritability: 50.2%). Interactions between aphid species, differences
in climatic conditions and the spatial distribution of aphid infestation were identified as possible factors impeding the
detection of QTLs. A pedigree analysis of simple sequence repeat (SSR) marker alleles closely associated with the QTL markers
revealed the presence of the alleles in other apple cultivars with reported aphid resistance (‘Wagener’, ‘Cox’s Orange Pippin’),
highlighting the genetic basis and also the potential for gene pyramiding of aphid resistance in apple. Finally, significant
QTLs for shoot length and stem diameter were identified, while there was no relationship between aphid resistance and plant
trait QTLs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
L. Pierantoni L. Dondini K.-H. Cho I.-S. Shin F. Gennari R. Chiodini S. Tartarini S.-J. Kang S. Sansavini 《Tree Genetics & Genomes》2007,3(4):311-317
Pear scab caused by Venturia pyrina is an economically important disease throughout the world and can cause severe crop loss in susceptible cultivars. The varying
range of susceptibility to pear scab in F1 populations has made it possible to identify quantitative trait loci (QTLs). Ninety-five
seedlings derived from the cross ‘Abbè Fétel’ (AF) × ‘Max Red Bartlett’ (MRB) were evaluated for scab resistance in greenhouse
tests, with 39% being classified as resistant, 33 as moderately susceptible and 28 as highly susceptible. Amplified fragment
length polymorphisms (157) and simple sequence repeats (41) were used to construct two maps, one of 908.1 cM (AF) and the
other of 879.8 cM (MRB). The analysis of the resistance data collected made it possible to identify two major QTLs on linkage
groups 3 and 7 associated with resistance to V. pyrina. Both QTLs explained 88% of the phenotypic variance and the log of odds values were higher than 10, suggesting the involvement
of two major genes in pear scab resistance.
L. Pierantoni and L. Dondini have contributed equally to this work. 相似文献
19.
V. G. M. Bus D. Chagné H. C. M. Bassett D. Bowatte F. Calenge J.-M. Celton C.-E. Durel M. T. Malone A. Patocchi A. C. Ranatunga E. H. A. Rikkerink D. S. Tustin J. Zhou S. E. Gardiner 《Tree Genetics & Genomes》2008,4(2):223-236
Woolly apple aphid (WAA; Eriosoma lanigerum Hausm.) can be a major economic problem to apple growers in most parts of the world, and resistance breeding provides a sustainable
means to control this pest. We report molecular markers for three genes conferring WAA resistance and placing them on two
linkage groups (LG) on the genetic map of apple. The Er1 and Er2 genes derived from ‘Northern Spy’ and ‘Robusta 5,’ respectively, are the two major genes that breeders have used to date
to improve the resistance of apple rootstocks to this pest. The gene Er3, from ‘Aotea 1’ (an accession classified as Malus sieboldii), is a new major gene for WAA resistance. Genetic markers linked to the Er1 and Er3 genes were identified by screening random amplification of polymorphic deoxyribonucleic acid (DNA; RAPD) markers across DNA
bulks from resistant and susceptible plants from populations segregating for these genes. The closest RAPD markers were converted
into sequence-characterized amplified region markers and the genome location of these two genes was assigned to LG 08 by aligning
the maps around the genes with a reference map of ‘Discovery’ using microsatellite markers. The Er2 gene was located on LG 17 of ‘Robusta 5’ using a genetic map developed in a M.9 × ‘Robusta 5’ progeny. Markers for each of
the genes were validated for their usefulness for marker-assisted selection in separate populations. The potential use of
the genetic markers for these genes in the breeding of apple cultivars with durable resistance to WAA is discussed. 相似文献
20.
The apple production in temperate regions with spring rains, the Scab caused by the fungus Venturia inaequalis is the most important constraint. To produce spotless apples and avoid damage that develops during storage, growers apply
fungicide on a regular or weather-determined basis. All major apple cultivars are highly susceptible to this disease. To limit
the need for fungicide applications, apple breeders are currently introgressing disease resistance from wild Malus accessions into commercial lines. The first attempts to do this were made 100 years ago. As apples are self-incompatible,
pseudo-backcrossing is used to eliminate unwanted traits from wild Malus and select new cultivars that are attractive to both producers and consumers. This process, from the first cross of a commercial
cultivar with a wild, disease-resistant Malus, is extremely long due to apple’s long juvenile phase, the need for more than seven backcross steps and the high heterozygosity
of this genus. Therefore, most of today’s scab-resistant cultivars rely on a single introduction of scab resistance from Malus floribunda 821, referred to as Vf. In this paper, we trace the history of Vf from its initial identification through its use in breeding
and commercial production. We sum up the literature describing how and where Vf resistance has been overcome by new pathotypes
of V. inaequalis. Finally, we describe the current knowledge of the genes behind Vf resistance, its mode of action and the use of Vf genes in gene technology. 相似文献