scholarly journals Pyramiding resistance genes and widening the genetic base of the apple (Malus × domestica Borkh.) crop

Italus Hortus ◽  
2021 ◽  
Vol 28 (1) ◽  
pp. 32
Author(s):  
Raffaele Testolin ◽  
Luigi Falginella ◽  
Alberto De Carli ◽  
Gloria De Mori ◽  
Guido Cipriani
Keyword(s):  
Molecular Markers ◽  
Disease Resistance ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Field Observations ◽  
Vf Gene ◽  
Malus Domestica Borkh ◽  
Genetic Base ◽  
Apple Cultivars ◽  
New Cultivars

Apple breeding is active worldwide and yet the apple crop is in a precarious state as it relies on few dominant cultivars and only the Rvi6 (formerly Vf) gene, that confers resistance to scab, has been extensively exploited in the cultivars entered the market in recent years. However, there are some 20 disease resistance genes described in apple and the apple germplasm includes thousands of accessions in the repositories. In this paper, a breeding programme is described, whereby 36 genotypes, including ancient and contemporary apple cultivars, were crossed to produce a new set of selections that combine extensive genetic resources with pyramided resistance genes to several apple diseases, such as scab and powdery mildew. The 110 cross combinations carried out successfully, of the 260 initially planned, produced 7,876 offsprings, reduced to 2,969 after screening with molecular markers associated with five resistance genes. Selections with three or two resistance genes and good agronomic characteristics were kept for further field observations with the aims of creating new cultivars for the market and new parents for future breeding projects

scholarly journals Identification of apple scab and powdery mildew resistance genes in Czech apple (Malus × domestica) genetic resources by PCR molecular markers

2011 ◽  
Vol 47 (No. 4) ◽  
pp. 156-165 ◽  
Author(s):  
J. Patzak ◽  
F. Paprštein ◽  
A. Henychová
Keyword(s):  
Molecular Markers ◽  
Powdery Mildew ◽  
Genetic Resources ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Mildew Resistance ◽  
Apple Cultivars

The presence of genes for resistance to scab (Venturia inaequalis) and powdery mildew (Podosphaera leucotricha) was studied using molecular markers in a sample of 279 apple cultivars from the Czech collection of apple genetic resources. The sample comprised 37 cultivars supposed to have the Vf gene for scab resistance, 97 reference world cultivars and 145 old and local cultivars. Six PCR molecular markers for the scab resistance genes Vf, Vm, Vbj, Vr and Vh and three PCR molecular markers for the powdery mildew resistance genes Pl-w, Pl-1 and Pl-d were used. The marker for the major scab resistance gene Vf was detected in all cultivars supposed to have Vf, except in Romus 1, and in the three small-fruited cultivars Malus Evereste, Golden Gem and Hilleri. The markers of the Vr and Vh scab resistance genes were detected in 22 cultivars in combination with the marker for Vf, in 56 reference world cultivars and in 82 old and local apple cultivars. PCR molecular markers for one or two of the powdery mildew resistance genes were detected in the small-fruited cultivars Malus Evereste, Golden Gem, prof. Sprengeri and Hilleri; and in the larger fruited cultivars Hagloe Crab, Borovinka and Tita Zetei. We did not find markers for the scab resistance genes Vm and Vbj in any of the studied cultivars. They are absent also in the remaining part of the Czech collection of apple genetic resources. PCR molecular markers are useful tools for the identification of resistance genes within apple germplasm collections and can be used to increase the number of sources for disease resistance in breeding programmes.

scholarly journals Sequencing and analysis of gerbera daisy leaf transcriptomes reveal disease resistance and susceptibility genes differentially expressed and associated with powdery mildew resistance

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Krishna Bhattarai ◽  
Ana Conesa ◽  
Shunyuan Xiao ◽  
Natalia A. Peres ◽  
David G. Clark ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Disease Resistance ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Disease Susceptibility ◽  
De Novo ◽  
Susceptibility Genes ◽  
Genetic Maps ◽  
Targeted Mutagenesis ◽  
Differentially Expressed

Abstract Background RNA sequencing has been widely used to profile genome-wide gene expression and identify candidate genes controlling disease resistance and other important traits in plants. Gerbera daisy is one of the most important flowers in the global floricultural trade, and powdery mildew (PM) is the most important disease of gerbera. Genetic improvement of gerbera PM resistance has become a crucial goal in gerbera breeding. A better understanding of the genetic control of gerbera resistance to PM can expedite the development of PM-resistant cultivars. Results The objectives of this study were to identify gerbera genotypes with contrasting phenotypes in PM resistance and sequence and analyze their leaf transcriptomes to identify disease resistance and susceptibility genes differentially expressed and associated with PM resistance. An additional objective was to identify SNPs and SSRs for use in future genetic studies. We identified two gerbera genotypes, UFGE 4033 and 06–245-03, that were resistant and susceptible to PM, respectively. De novo assembly of their leaf transcriptomes using four complementary pipelines resulted in 145,348 transcripts with a N50 of 1124 bp, of which 67,312 transcripts contained open reading frames and 48,268 were expressed in both genotypes. A total of 494 transcripts were likely involved in disease resistance, and 17 and 24 transcripts were up- and down-regulated, respectively, in UFGE 4033 compared to 06–245-03. These gerbera disease resistance transcripts were most similar to the NBS-LRR class of plant resistance genes conferring resistance to various pathogens in plants. Four disease susceptibility transcripts (MLO-like) were expressed only or highly expressed in 06–245-03, offering excellent candidate targets for gene editing for PM resistance in gerbera. A total of 449,897 SNPs and 19,393 SSRs were revealed in the gerbera transcriptomes, which can be a valuable resource for developing new molecular markers. Conclusion This study represents the first transcriptomic analysis of gerbera PM resistance, a highly important yet complex trait in a globally important floral crop. The differentially expressed disease resistance and susceptibility transcripts identified provide excellent targets for development of molecular markers and genetic maps, cloning of disease resistance genes, or targeted mutagenesis of disease susceptibility genes for PM resistance in gerbera.

Effectiveness of major resistance genes and identification of new sources for disease resistance in wheat

2011 ◽  
Vol 59 (3) ◽  
pp. 241-248 ◽  
Author(s):  
G. Vida ◽  
M. Cséplő ◽  
G. Gulyás ◽  
I. Karsai ◽  
T. Kiss ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Genetic Material ◽  
Leaf Rust Resistance ◽  
Wheat Varieties ◽  
Major Resistance Genes ◽  
Greenhouse Tests

Among the factors which determine yield reliability an important role is played by disease resistance. One of the breeding aims in the Martonvásár institute is to develop wheat varieties with resistance to major diseases. The winter wheat varieties bred in Martonvásár are examined in artificially inoculated nurseries and greenhouses for resistance to economically important pathogens. The effectiveness of designated genes for resistance to powdery mildew and leaf rust has been monitored over a period of several decades. None of the designated major resistance genes examined in greenhouse tests is able to provide complete resistance to powdery mildew; however, a number of leaf rust resistance genes provide full protection against pathogen attack (Lr9, Lr19, Lr24, Lr25, Lr28 and Lr35). In the course of marker-assisted selection, efficient resistance genes (Lr9, Lr24, Lr25 and Lr29) have been incorporated into Martonvásár wheat varieties. The presence of Lr1, Lr10, Lr26, Lr34 and Lr37 in the Martonvásár gene pool was identified using molecular markers. New sources carrying alien genetic material have been tested for powdery mildew and leaf rust resistance. Valuable Fusarium head blight resistance sources have been identified in populations of old Hungarian wheat varieties. Species causing leaf spots (Pyrenophora tritici-repentis, Septoria tritici and Stagonospora nodorum) have gradually become more frequent over the last two decades. Tests on the resistance of the host plant were begun in Martonvásár four years ago and regular greenhouse tests on seedlings have also been initiated.

Linkage mapping of powdery mildew and greenbug resistance genes on recombinant 1RS from 'Amigo' and 'Kavkaz' wheat–rye translocations of chromosome 1RS.1AL

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 292-298 ◽  
Author(s):  
Yehia Mater ◽  
Stephen Baenziger ◽  
Kulvinder Gill ◽  
Robert Graybosch ◽  
Lynda Whitcher ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Dna Sequences ◽  
Secale Cereale ◽  
Polyacrylamide Gel Electrophoresis ◽  
Rflp Markers ◽  
Resistance Locus ◽  
Greenbug Resistance

Cultivated rye (Secale cereale L., 2n = 2x = 14, RR) is an important source of genes for insect and disease resistance in wheat (Triticum aestivum L., 2n = 6x = 42). Rye chromosome arm 1RS of S. cereale 'Kavkaz' originally found as a 1BL.1RS translocation, carries genes for disease resistance (e.g., Lr26, Sr31, Yr9, and Pm8), while 1RS of the S. cereale 'Amigo' translocation (1RSA) carries a single resistance gene for greenbug (Schizaphis graminum Rondani) biotypes B and C and also carries additional disease-resistance genes. The purpose of this research was to identify individual plants that were recombinant in the homologous region of.1AL.1RSV and 1AL.1RSA using both molecular and phenotypic markers. Secale cereale 'Nekota' (1AL.1RSA) and S. cereale 'Pavon 76' (1AL.1RSV) were mated and the F1 was backcrossed to 'Nekota' (1AL.1AS) to generate eighty BC1F2:3 families (i.e., ('Nekota' 1AL.1RSA × 'Pavon 76' 1AL.1RSV) × 'Nekota' 1AL.1AS). These families were genotyped using the secalin–gliadin grain storage protein banding pattern generated with polyacrylamide gel electrophoresis to discriminate 1AL.1AS/1AL.1RS heterozygotes from the 1AL.1RSA+V and 1AL.1AS homozygotes. Segregation of the secalin locus and PCR markers based on the R173 family of rye specific repeated DNA sequences demonstrated the presence of recombinant 1AL.1RSA+V families. Powdery mildew (Blumeria graminis) and greenbug resistance genes on the recombinant 1RSA+V arm were mapped in relation to the Sec-1 locus, 2 additional protein bands, 3 SSRs, and 13 RFLP markers. The resultant linkage map of 1RS spanned 82.4 cM with marker order and spacing showing reasonable agreement with previous maps of 1RS. Fifteen markers lie within a region of 29.7 cM next to the centromere, yet corresponded to just 36% of the overall map length. The map position of the RFLP marker probe mwg68 was 10.9 cM distal to the Sec-1 locus and 7.8 cM proximal to the powdery mildew resistance locus. The greenbug resistance gene was located 2.7 cM proximal to the Sec-1 locus.Key words: microsatellites, SSRs, RFLP, secalin-gliadin, alien genes introgression.

scholarly journals Map-based isolation of disease resistance genes from bread wheat: cloning in a supersize genome

2005 ◽  
Vol 85 (2) ◽  
pp. 93-100 ◽  
Author(s):  
BEAT KELLER ◽  
CATHERINE FEUILLET ◽  
NABILA YAHIAOUI
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Leaf Rust ◽  
Bread Wheat ◽  
Genetic Map ◽  
Resistance Genes ◽  
Positional Cloning ◽  
Repetitive Sequences ◽  
Near Future ◽  
Genome Projects

The genome of bread wheat is hexaploid and contains 1·6×1010 bp of DNA, of which more than 80% is repetitive sequences. Its size and complexity represent a challenge for the isolation of agronomically important genes, for which we frequently know only their position on the genetic map. Recently, new genomic resources and databases from genome projects have simplified the molecular analysis of the wheat genome. The first genes to be isolated from wheat by map-based cloning include three resistance genes against the fungal diseases powdery mildew and leaf rust. In this review, we will describe the approaches and resources that have contributed to this progress, and discuss genomic strategies that will simplify positional cloning in wheat in the near future.

scholarly journals Resistance of Spring Barley Varieties to Powdery Mildew in theCzechRepublicin 1971–2000

2011 ◽  
Vol 39 (No. 2) ◽  
pp. 31-44 ◽  
Author(s):  
A. Dreiseitl ◽  
P. Pařízek
Keyword(s):  
Molecular Markers ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
High Resistance ◽  
Spring Barley ◽  
Resistant Variety ◽  
High Susceptibility ◽  
Pathogen Population ◽  
Major Resistance Gene ◽  
Resistance Score

Resistance to powdery mildew of 127 spring barley varieties was evaluated in 702 official variety trials, using scores from 1 to 9. Trials with sufficient disease severity were only analysed. Varieties possessing the resistance genes Mla7 (Elgina), Ml(Kr) (BR-1519), Mla13 (Koral) and mlo (Forum) were among the most resistant ones. The varieties Diamant, HE-3527, HE-3631, II/61-FUDII and Zefir showed high susceptibility. Fifteen varieties, carrying the genes Mla1, Mla3, Mla6, Mla9, Mla13, Ml(Kr) and Ml(Sc), were in the first years of testing highly resistant, but became susceptible later. The score of the most resistant variety ranged each year from 8.05 to 9.00, only in 1987–1991 it was lower. Since the pathogen population rapidly adapted to most resistance genes in the mid eighties, no resistant variety was found in 1987–1989. From 1986 to 1995 on average only 6.6% of the tested varieties were resistant, but there was no variety with resistance score above 8.50. High resistance was typical for varieties possessing an effective major resistance gene. Since the resistance of such varieties was not durable, we recommend breeding of varieties with at least two fully effective resistance genes, using molecular markers.  

scholarly journals Genome-Wide Identification of Powdery Mildew Resistance in Common Bean (Phaseolus vulgaris L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Papias H. Binagwa ◽  
Sy M. Traore ◽  
Marceline Egnin ◽  
Gregory C. Bernard ◽  
Inocent Ritte ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Common Bean ◽  
Resistance Genes ◽  
Significant Snps ◽  
Leucine Rich Repeat ◽  
Genome Wide ◽  
Disease Resistance Protein ◽  
Resistance Protein ◽  
The Common

Genome-wide association studies (GWAS) have been utilized to detect genetic variations related to several agronomic traits and disease resistance in common bean. However, its application in the powdery mildew (PM) disease to identify candidate genes and their location in the common bean genome has not been fully addressed. Single-nucleotide polymorphism (SNP) genotyping with a BeadChip containing 5398 SNPs was used to detect genetic variations related to PM disease resistance in a panel of 211 genotypes grown under two field conditions for two consecutive years. Significant SNPs identified on chromosomes Pv04 and Pv10 were repeatable, ensuring the phenotypic data’s reliability and the causal relationship. A cluster of resistance genes was revealed on the Pv04 of the common bean genome, coiled-coil-nucleotide-binding site–leucine-rich repeat (CC-NBS-LRR, CNL), and Toll/interleukin-1 receptor-nucleotide-binding site–leucine-rich repeat type (TIR-NBS-LRR, TNL)-like resistance genes were identified. Furthermore, two resistance genes, Phavu_010G1320001g and Phavu_010G136800g, were also identified on Pv10. Further sequence analysis showed that these genes were homologs to the disease-resistance protein (RLM1A-like) and the putative disease-resistance protein (At4g11170.1) in Arabidopsis. Significant SNPs related to two LRR receptor-like kinases (RLK) were only identified on Pv11 in 2018. Many genes encoding the auxin-responsive protein, TIFY10A protein, growth-regulating factor five-like, ubiquitin-like protein, and cell wall RBR3-like protein related to PM disease resistance were identified nearby significant SNPs. These results suggested that the resistance to PM pathogen involves a network of many genes constitutively co-expressed.

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