scholarly journals Development of isogenic lines for resistance to Septoria tritici blotch in wheat

2011 ◽  
Vol 47 (Special Issue) ◽  
pp. S98-S101 ◽  
Author(s):  
S.B. Goodwin ◽  
I. Thompson
Keyword(s):  
Molecular Markers ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Backcross Progeny ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
The Past ◽  
Wheat Improvement ◽  
Improvement Programs ◽  
Elite Germplasm

Septoria tritici blotch (STB), caused by the fungus Mycosphaerella graminicola (asexual stage: Septoria tritici), is one of the most economically important diseases of wheat worldwide. During the past decade 13 genes for resistance to STB have been identified and several molecular markers have been developed. However, analysis of resistance gene expression and utility for plant improvement programs would be increased if the resistance genes were isolated in a common susceptible background. To address this problem, a program was begun to backcross resistance genes Stb1–8 into two susceptible wheat cultivars. Work with genes Stb2, Stb3, Stb6 and Stb8 has proceeded the farthest. Resistance gene Stb3 is dominant, while Stb2 may be recessive. This will be the first report of recessive resistance to STB if confirmed. Molecular markers linked to the resistance genes are being validated in the backcross progeny and should provide the materials for efficient introgression of these genes into elite germplasm for future wheat improvement.

scholarly journals Resistance of Wheat Line Kavkaz-K4500 L.6.A.4 to Septoria Tritici Blotch Controlled by Isolate-Specific Resistance Genes

2005 ◽  
Vol 95 (6) ◽  
pp. 664-671 ◽  
Author(s):  
L. Chartrain ◽  
S. T. Berry ◽  
J. K. M. Brown
Keyword(s):  
Resistance Genes ◽  
Specific Resistance ◽  
Field Resistance ◽  
Field Conditions ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
High Susceptibility ◽  
Sources Of Resistance ◽  
Wheat Improvement ◽  
The Uk

The International Maize and Wheat Improvement Center (CIMMYT), Mexico, germplasm-derived wheat (Triticum aestivum) Kavkaz-K4500 L.6.A.4 (KK) is one of the major sources of resistance to Septoria tritici blotch (STB). KK is resistant to STB in field conditions in the UK even though a large majority of Mycosphaerella graminicola isolates are virulent to it. The genetics of the resistance of KK to four isolates of M. graminicola were investigated. KK has at least five isolate-specific resistance genes including Stb6 on chromosome 3A plus a second gene for resistance to isolate IPO323, two genes on chromosome 4A, both in the region where Stb7 is located with one designated as Stb12, and a gene designated Stb10 on chromosome 1D. Taken together, the widespread use of KK as a source of resistance to STB, its high resistance in field conditions, and its high susceptibility to M. graminicola isolates, which are virulent to all its resistance genes, suggest that high levels of field resistance to STB might be achieved by pyramiding several isolate-specific resistance genes.

Molecular screening of potato varieties bred by Falenki Breeding station for resistance to phytopathogens

2021 ◽  
Vol 22 (3) ◽  
pp. 340-350
Author(s):  
A. V. Bakulina ◽  
L. S. Savintseva ◽  
O. N. Bashlakova ◽  
N. F. Sintsova
Keyword(s):  
Molecular Markers ◽  
Resistance Gene ◽  
Potato Virus ◽  
Resistance Genes ◽  
Dna Marker ◽  
Potato Virus X ◽  
Pcr Analysis ◽  
Gene Marker ◽  
Breeding Station ◽  
Short Period

The genotypes of potatoes bred by Falenki Breeding station were studied for the presence of resistance genes markers to the following pathogens: Globodera rostochiensis, Globodera pallidа, Synchytrium endobioticum, potato virus X (PVХ) and potato virus Y (PVY). The method of multiplex PCR analysis was used. The varieties Shurminsky 2, Alisa, Viza, Chayka, Ognivo, Darik, Gloriya, Golubka, Virazh and a promising variety sample 56-09 were studied. In most (8 out of 10) genotypes, marker linked to the Sen1 gene of resistance to S. endobioticum was identified. DNA marker of the G. rostochiensis resistance gene (H1) and the G. pallida resistance gene marker (Gpa2) were found in six genotypes. The marker of the PVX resistance gene (Rx1) was detected in the varieties Shurminsky 2, Alisa, Chayka, Golubka, and Virazh. It has been established that none of the studied potato genotypes carries markers RYSC3, Ry186, YES3-3A linked to the PVY resistance genes. Although in the field, resistance was detected in the samples Chayka, Darik, Virazh, Alisa. Molecular markers linked to the largest number of resistance genes studied (H1, Gpa2, Sen1, and Rx1) were identified in the varieties Shurminsky 2, Golubka, and Virazh. Among the DNA markers used in the work, the data of potato genotype assessment using markers of virus resistance genes (PVX, RYSC3, Ry186, YES3-3A) were less consistent with field observations. The use of molecular markers makes it possible to determine the presence of resistance genes and assess the prospects of a sample in a short period of time, but, at the same time, requires careful choice of a DNA marker that is highly correlated with the manifestation of the trait.

Identification by genome scanning approach (GSA) of a microsatellite tightly associated with the apple scab resistance gene Vm

Genome ◽  
2005 ◽  
Vol 48 (4) ◽  
pp. 630-636 ◽  
Author(s):  
A Patocchi ◽  
M Walser ◽  
S Tartarini ◽  
G A.L Broggini ◽  
F Gennari ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Linkage Group ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Simple Sequence Repeat ◽  
Apple Scab ◽  
Scab Resistance ◽  
Sequence Repeat ◽  
Genome Scanning ◽  
Simple Sequence

For all known major apple scab resistance genes except Vr, molecular markers have been published. However, the precise position of some of these genes, in the apple genome, remains to be identified. Knowledge about the relative position of apple scab resistance genes is necessary to preliminarily evaluate the probability of success of their pyramidization. Pyramidization of different resistance genes into the same genotype is a reliable way to create cultivars with durable apple scab resistance. Applying the genome scanning approach (GSA), we identified the linkage group of the scab resistance gene Vm, derived from Malus micromalus, and we found a new molecular marker tightly associated with the gene. The simple sequence repeat Hi07h02, previously mapped on linkage group 17, cosegregates with the Vm gene (no recombinants in the 95 plants tested). The already published sequence-characterized amplified region Vm marker OPB12687 was found to be linked at about 5 cM from the resistance gene and, therefore, this marker also maps on linkage group 17 of apple. This is the first report of the discovery of a major apple scab resistance gene on linkage group 17. The advantages of using GSA for the identification of molecular markers for qualitative traits are discussed.Key words: Malus, Venturia inaequalis, mapping, simple sequence repeat.

Mining synthetic hexaploids for multiple disease resistance to improve bread wheat

2008 ◽  
Vol 59 (5) ◽  
pp. 421 ◽  
Author(s):  
F. C. Ogbonnaya ◽  
M. Imtiaz ◽  
H. S. Bariana ◽  
M. McLean ◽  
M. M. Shankar ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Leaf Rust ◽  
Resistance Gene ◽  
Bread Wheat ◽  
Stripe Rust ◽  
Stem Rust ◽  
Wheat Yield ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Seedling Resistance

A collection of 253 synthetic hexaploid wheats (SHWs) produced from 192 Aegilops tauschii accessions and 39 elite durum varieties were studied to identify, characterise, and evaluate potentially untapped diversity of disease resistance in wheat. The diseases for which resistance was sought included cereal cyst nematode (CCN), root lesion nematode (RLN), Stagonospora nodorum blotch (SNB), Septoria tritici blotch (STB), and the 3 rusts, leaf rust, stem rust, and stripe rust, all important diseases of bread wheat worldwide, which can severely reduce wheat yield and quality. The SHWs exhibited a wide spectrum of resistance to the 8 pathogens. The frequency of disease-resistant SHWs ranged from 1% for one species of RLN (Pratylenchus neglectus), 3% and 10% for Septoria nodorum leaf and glume blotch, 10% for seedling resistance to yellow leaf spot, 16% for CCN, 21% for the second species of RLN (Pratylenchus thornei), 73% for Septoria tritici blotch, and 15%, 40%, and 24% for leaf rust, stem rust, and stripe rust, respectively. Five SHWs, Aus26860, Aus30258, Aus30294, Aus30301, and Aus30304, exhibited high levels of resistance to CCN, YLP, STB, LR, and SR, while 56 SHWs showed resistance to either 3 or 4 diseases. The genetics of resistance to CCN in some of the SHWs revealed that some of the accessions carry the same CCN gene(s) against pathotype Ha13, while others may carry different resistance gene(s). Additional studies were carried out to understand the relationship between the resistances identified in SHWs and the ones already present in common wheat, in particular the resistance genes Cre1 and Cre3 against CCN. The use of perfect markers associated with Cre1 and Cre3 suggested that some SHWs may carry a new CCN resistance gene(s), which could be deployed in breeding programs to increase the diversity of available resistance. The identification of SHWs with resistance to a range of diseases provides an opportunity to generate genetic knowledge and resistant germplasm to be used in future variety development.

scholarly journals QTL Mapping and Transcriptome Analysis to Identify Differentially Expressed Genes Induced by Septoria Tritici Blotch Disease of Wheat

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 510 ◽  
Author(s):  
Odilbekov ◽  
He ◽  
Armoniené ◽  
Saripella ◽  
Henriksson ◽  
...  
Keyword(s):  
Qtl Mapping ◽  
Differentially Expressed Genes ◽  
Resistance Genes ◽  
Transcriptome Analysis ◽  
Resistance Mechanism ◽  
Transcriptome Profiling ◽  
Wheat Breeding ◽  
Differentially Expressed ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici

Resistance to Septoria tritici blotch (STB) is an economically important trait in many wheat-breeding programs across the world. Several quantitative trait loci (QTL) for STB resistance were identified in wheat but due to the dynamic pathogen population it is necessary to continuously identify new resistance genes/QTL and determine the underlying resistance mechanism. In this work, we integrated QTL mapping and transcriptome profiling to identify candidate genes underlying QTL associated with STB resistance in bread wheat at the seedling stage. The results revealed four QTL on chromosomes 1BS, 1BL, 3AS and 3DL for STB resistance. Among these, two QTL on 2BL and 3DL were mapped for chlorosis, necrosis and pycnidia while the other two on 1BS and 3AS were associated with necrosis and pycnidia. Among the four identified QTL, genes were identified in three QTL (1BS, 2BL and 3DL). In total, 238 differentially expressed genes (DEGs) were localized in 1BS, 16 DEGs in 2BL and 80 DEGs in 3DL QTL region respectively. F-box protein, NBS-LRR disease resistance genes and receptor-like protein kinase were the most over-represented. The results emphasize the importance of integrating QTL and transcriptome analysis to accelerate the identification of key genes underlying the traits of interest.

scholarly journals Inheritance of Race-Specific Resistance to Mycosphaerella graminicola in Wheat

2002 ◽  
Vol 92 (2) ◽  
pp. 138-144 ◽  
Author(s):  
C. A. McCartney ◽  
A. L. Brûlé-Babel ◽  
L. Lamari
Keyword(s):  
Resistance Genes ◽  
Tetraploid Wheat ◽  
Gene Interaction ◽  
Mycosphaerella Graminicola ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Controlled Environment ◽  
High Level ◽  
Wheat Lines ◽  
Level Resistance

Mycosphaerella graminicola causes Septoria tritici blotch of hexaploid and tetraploid wheat. The inheritance of high-level resistance to Septoria tritici blotch was studied in controlled environment experiments. Intraspecific reciprocal crosses were made between hexaploid wheat lines Salamouni, ST6, Katepwa, and Erik, and the tetraploid wheat lines Coulter and 4B1149. Parental, F1, F2, F3, BC1F1, and BC1F2 populations were evaluated for reaction to isolates MG2 and MG96-36 of M. graminicola. Resistance was controlled by incompletely dominant nuclear genes in all cases. Salamouni had three independent resistance genes to isolate MG2, two of which also controlled resistance to isolate MG96-36. ST6 had a single resistance gene to isolate MG2 and none to isolate MG96-36. The resistance genes in Salamouni and ST6 were not allelic. Two independent genes control resistance to isolate MG2 in Coulter, one of which also controlled resistance to isolate MG96-36. These data are consistent with a gene-for-gene interaction in the wheat-M. graminicola pathosystem.

Resistance gene analogues are clustered on chromosome 3 of sugar beet and cosegregate with QTL for rhizomania resistance

Genome ◽  
2007 ◽  
Vol 50 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Jens Christoph Lein ◽  
Katrin Asbach ◽  
Yanyan Tian ◽  
Daniela Schulte ◽  
Chunyan Li ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Sugar Beet ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Bac Library ◽  
Artificial Chromosome ◽  
Chromosome 3 ◽  
Resistance Locus ◽  
Resistant Varieties ◽  
Rhizomania Resistance

Worldwide, rhizomania is the most important disease of sugar beet. The only way to control this disease is to use resistant varieties. Four full-length resistance gene analogues (RGAs) from sugar beet (cZR-1, cZR-3, cZR-7, and cZR-9) were used in this study. Their predicted polypeptides carry typical nucleotide-binding sites (NBSs) and leucin-rich repeat (LRR) regions, and share high homology to various plant virus resistance genes. Their corresponding alleles were cloned and sequenced from a rhizomania resistant genotype. The 4 RGAs were mapped as molecular markers, using sequence-specific primers to determine their linkage to the rhizomania resistance locus Rz1 in a population segregating for rhizomania resistance. One cZR-3 allele, named Rz-C, together with 5 other molecular markers, mapped to the Rz1 locus on chromosome 3 and cosegregated with quantitative trait loci for rhizomania resistance. After screening a bacterial artificial chromosome (BAC) library, 25 cZR-3-positive BACs were identified. Of these, 15 mapped within an interval of approximately 14 cM on chromosome 3, in clusters close to the Rz1 locus. Rz-C differentiates between susceptible and resistant beet varieties, and its transcripts could be detected in all rhizomania resistant varieties investigated. The potential of this RGA marker for cloning of rhizomania resistance genes is discussed.

scholarly journals Physical Mapping of Pm57, a Powdery Mildew Resistance Gene Derived from Aegilops searsii

2019 ◽  
Author(s):  
Zhenjie Dong ◽  
Xiubin Tian ◽  
Chao Ma ◽  
Qing Xia ◽  
Beilin Wang ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Powdery Mildew ◽  
Binding Site ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Nucleotide Binding ◽  
Leucine Rich Repeat ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance

Powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is one of many severe diseases that threaten bread wheat (Triticum aestivum L.) yield and quality worldwide. The discovery and deployment of powdery mildew resistance genes (Pm) can prevent this disease epidemic in wheat. In a previous study, we transferred the powdery mildew resistance gene Pm57 from Aegilops searsii into common wheat and cytogenetically mapped the gene in a chromosome region with the fraction length (FL) 0.75-0.87, which represents 12% of 2Ss#1 segment on the long arm of chromosome 2Ss#1. In this study, we performed RNA-Seq on three infected and mock-infected wheat-Ae. searsii 2Ss#1 introgression lines with Bgt-isolates inoculation at 0, 12, 24, and 48 hours after inoculation. Then we designed 79 molecular markers based on transcriptome sequences and physically mapped them to Ae. searsii chromosome 2Ss#1- in seven intervals. We used these markers to identify 46 wheat-Ae. searsii 2Ss#1 recombinants induced by ph1b, a deletion mutant of pairing homoelogous (Ph) genes. Analysis of the 46 ph1b-induced 2Ss#1L recombinants with different Bgt-responses using 28 2Ss#1L-specific molecular markers in the interval FL0.72-0.87 where Pm57 is located, and the flanking intervals, we physically mapped Pm57 gene on the long arm of 2Ss#1 in a 5.13 Mb genomic region, which was flanked by markers X67593 (773.72 Mb) and X62492 (778.85 Mb). By comparative synteny analysis of the corresponding region on chromosome 2B in Chinese spring (T. aestivum L.) with other model species we identified ten genes that are putative plant defense-related (R) genes which includes six coiled-coil nucleotide-binding site-leucine-rich repeat (CNL), three nucleotide-binding site-leucine-rich repeat (NL) and a leucine-rich receptor-like repeat (RLP) encoding proteins. This study will lay a foundation for further cloning of Pm57, and benefit the understanding of interactions between resistance genes of wheat and powdery mildew pathogens.

scholarly journals Genetic Diversity at Resistance Gene Clusters in Wild Populations of Lactuca

2000 ◽  
Author(s):  
Richard Michelmore ◽  
Eviatar Nevo ◽  
Abraham Korol ◽  
Tzion Fahima
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Disease Control ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Research Work ◽  
Ex Situ ◽  
Large Numbers ◽  
Major Cluster ◽  
Genetic Mechanisms

Genetic resistance is often the least expensive, most effective, and ecologically-sound method of disease control. It is becoming apparent that plant genomes contain large numbers of disease resistance genes. However, the numbers of different resistance specificities within a genepool and the genetic mechanisms generating diversity are poorly understood. Our objectives were to characterize diversity in clusters of resistance genes in wild progenitors of cultivated lettuce in Israel and California in comparison to diversity within cultivated lettuce, and to determine the extent of gene flow, recombination, and genetic instability in generating variation within clusters of resistance genes. Genetic diversity of resistance genes was analyzed in wild and cultivated germplasm using molecular markers derived from lettuce resistance gene sequences of the NBS-LRR type that mapped to the major cluster if resistance genes in lettuce (Sicard et al. 1999). Three molecular markers, one microsatellite marker and two SCAR markers that amplified LRR- encoding regions, were developed from sequences of resistance gene homologs at the Dm3 cluster (RGC2s) in lettuce. Variation for these markers was assessed in germplasm including 74 genotypes of cultivated lettuce, L. saliva and 71 accessions of the three wild Lactuca spp., L. serriola, L. saligna and L. virosa that represent the major species in the sexually accessible genepool for lettuce. Diversity was also studied within and between natural populations of L. serriola from Israel and California. Large numbers of haplotypes were detected indicating the presence of numerous resistance genes in wild species. We documented a variety of genetic events occurring at clusters of resistance genes for the second objective (Sicard et al., 1999; Woo el al., in prep; Kuang et al., in prepb). The diversity of resistance genes in haplotypes provided evidence for gene duplication and unequal crossing over during the evolution of this cluster of resistance genes. Comparison of nine resistance genes in cv. Diana identified 22 gene conversion and five intergenic recombinations. We cloned and sequenced a 700 bp region from the middle of RGC2 genes from six genotypes, two each from L. saliva, L. serriola, and L. saligna . We have identified over 60 unique RGC2 sequences. Phylogenetic analysis surprisingly demonstrated much greater similarity between than within genotypes. This led to the realization that resistance genes are evolving much slower than had previously been assumed and to a new model as to how resistance genes are evolving (Michelmore and Meyers, 1998). The genetic structure of L. serriola was studied using 319 AFLP markers (Kuang et al., in prepa). Forty-one populations from Turkey, Armenia, Israel, and California as well as seven European countries were examined. AFLP marker data showed that the Turkish and Armenian populations were the most polymorphic populations and the European populations were the least. The Davis, CA population, a recent post-Columbian colonization, showed medium genetic diversity and was genetically close to the Turkish populations. Our results suggest that Turkey - Armenia may be the center of origin and diversity of L. serriola and may therefore have the greatest diversity of resistance genes. Our characterization of the diversity of resistance genes and the genetic mechanisms generating it will allow informed exploration, in situ and ex situ conservation, and utilization of germplasm resources for disease control. The results of this project provide the basis for our future research work, which will lead to a detailed understanding of the evolution of resistance genes in plants.

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