scholarly journals Characterization, Identification and Evaluation of Wheat-Aegilops sharonensis Chromosome Derivatives

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaolu Wang ◽  
Zhihui Yu ◽  
Hongjin Wang ◽  
Jianbo Li ◽  
Ran Han ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew Resistance ◽  
Wheat Breeding ◽  
Addition Line ◽  
Wild Relative ◽  
Powdery Mildew Resistance Gene ◽  
Molecular Cytogenetic ◽  
Wheat Improvement ◽  
Aegilops Sharonensis ◽  
Resistance Source

Aegilops sharonensis, a wild relative of wheat, harbors diverse disease and insect resistance genes, making it a potentially excellent gene source for wheat improvement. In this study, we characterized and evaluated six wheat-A. sharonensis derivatives, which included three disomic additions, one disomic substitution + monotelosomic addition and two disomic substitution + disomic additions. A total of 51 PLUG markers were developed and used to allocate the A. sharonensis chromosomes in each of the six derivatives to Triticeae homoeologous groups. A set of cytogenetic markers specific for A. sharonensis chromosomes was established based on FISH using oligonucleotides as probes. Molecular cytogenetic marker analysis confirmed that these lines were a CS-A. sharonensis 2Ssh disomic addition, a 4Ssh disomic addition, a 4Ssh (4D) substitution + 5SshL monotelosomic addition, a 6Ssh disomic addition, a 4Ssh (4D) substitution + 6Ssh disomic addition and a 4Ssh (4D) substitution + 7Ssh disomic addition line, respectively. Disease resistance investigations showed that chromosome 7Ssh of A. sharonensis might harbor a new powdery mildew resistance gene, and therefore it has potential for use as resistance source for wheat breeding.

Characterization of the Powdery Mildew Resistance Gene in Wheat Breeding Line KN0816 and its Evaluation in Marker-Assisted Selection

Plant Disease ◽  
2021 ◽  
Author(s):  
Wenrui Wang ◽  
Huagang He ◽  
Huiming Gao ◽  
Hongxing Xu ◽  
Wenyue Song ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Gene ◽  
Marker Assisted Selection ◽  
Powdery Mildew Resistance ◽  
Wheat Breeding ◽  
Agronomic Performance ◽  
Breeding Line ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease seriously threatening yield and quality of common wheat (Triticum aestivum L., 2n=6x=42, AABBDD). Characterization of resistance genes against powdery mildew is useful in parental selection and for developing disease resistant cultivars. Chinese wheat breeding line KN0816 has superior agronomic performance and resistance to powdery mildew at all growth stages. Genetic analysis using populations of KN0816 crossed with different susceptible parents indicated that a single dominant gene, tentatively designated PmKN0816, conferred seedling resistance to different Bgt isolates. Using a bulked segregant analysis (BSA), PmKN0816 was mapped to the Pm6 interval on chromosome arm 2BL using polymorphic markers linked to the catalogued genes Pm6, Pm52, and Pm64, and flanked by markers CISSR02g-6 and CIT02g-2 both with genetic distances of 0.7 cM. Analysis of closely linked molecular markers indicated that the marker alleles of PmKN0816 differed from those of other powdery mildew resistance genes on 2BL, including Pm6, Pm33, Pm51, Pm64, and PmQ. Based on the genetic and physical locations and response pattern to different Bgt isolates, PmKN0816 is most likely a new powdery mildew resistance gene and confers effective resistance to all the 14 tested Bgt isolates. In view of the elite agronomic performance of KN0816 combined with the resistance, PmKN0816 is expected to become a valuable resistance gene in wheat breeding. To transfer PmKN0816 to different genetic backgrounds using marker-assisted selection (MAS), closely linked markers of PmKN0816 were evaluated and four of them (CIT02g-2, CISSR02g-6, CIT02g-10, and CIT02g-17) were confirmed to be applicable for MAS in different genetic backgrounds.

scholarly journals Advances in Wheat and Pathogen Genomics: Implications for Disease Control

2018 ◽  
Vol 56 (1) ◽  
pp. 67-87 ◽  
Author(s):  
Beat Keller ◽  
Thomas Wicker ◽  
Simon G. Krattinger
Keyword(s):  
Disease Resistance ◽  
Molecular Level ◽  
Resistance Breeding ◽  
Wheat Breeding ◽  
The Past ◽  
Wheat Improvement ◽  
Disease Resistance Breeding ◽  
Near Future ◽  
New Cultivars ◽  
Made In

The gene pool of wheat and its wild and domesticated relatives contains a plethora of resistance genes that can be exploited to make wheat more resilient to pathogens. Only a few of these genes have been isolated and studied at the molecular level. In recent years, we have seen a shift from classical breeding to genomics-assisted breeding, which makes use of the enormous advancements in DNA sequencing and high-throughput molecular marker technologies for wheat improvement. These genomic advancements have the potential to transform wheat breeding in the near future and to significantly increase the speed and precision at which new cultivars can be bred. This review highlights the genomic improvements that have been made in wheat and its pathogens over the past years and discusses their implications for disease-resistance breeding.

Impacts of breeding on international collaborative wheat improvement

2006 ◽  
Vol 144 (1) ◽  
pp. 3-17 ◽  
Author(s):  
M. P. REYNOLDS ◽  
N. E. BORLAUG
Keyword(s):  
Disease Resistance ◽  
Genetic Resources ◽  
Developing World ◽  
Agricultural Research ◽  
Green Revolution ◽  
Wheat Breeding ◽  
Yield Potential ◽  
International Agricultural Research ◽  
Wheat Improvement ◽  
Modern Varieties

For over 40 years a collaborative network of publicly funded international wheat scientists has made a significant contribution to food security in the developing world. Thousands of modern wheat varieties (MVs) have been released for use in both favourable and marginal environments on well over 50 million hectares. The yield increases associated with genetic improvement in yield potential and adaptation to biotic and abiotic stresses are well documented. Millions of small-scale farmers in the developing world have benefited. While this so-called ‘Green Revolution’ displaced landraces in favour of more productive MVs, these and other genetic resources, held in trust by international organizations, have been utilized to improve the inherent genetic diversity of modern varieties. Furthermore, the result of increased yields reduced the need to bring natural ecosystems under cultivation, by as much as a billion hectares.Although international wheat breeding has its origins in the 1940s, recognition of a common scientific basis of agricultural problems worldwide was highlighted by the creation of International Agricultural Research Centres (IARCs) which included the International Maize and Wheat Improvement Centre (CIMMYT) established in 1965. This grew into a larger network called the Consultative Group for International Agricultural Research (CGIAR) now comprising 15 IARCs, including the International Centre for Agricultural Research in the Dry Areas (ICARDA) established in Syria in 1977, another key player in the international wheat and barley breeding network. Two of the major coordination responsibilities of CIMMYT are maintaining the world collection of wheat genetic resources – a public good protected by international treaty – and the facilitation of the International Wheat Nurseries.After the initial impact of the Green Revolution in high production zones through exploitation of Rht-B1 and Rht-D1 dwarfing genes in conjunction with disease resistance, international breeding encompassed more challenging environments through, for example, international shuttle breeding between Brazil and Mexico to overcome problems associated with acid soils that restricted adoption of MVs. Another example is drought, which affects at least 30 million ha of wheat in the developing world. The approach focused initially on exploiting the inherent yield potential and disease resistance of MVs and later combined this with new stress-adaptive traits from wild wheat ancestors through wide crossing techniques. Adoption of modern varieties has increased substantially in drier areas between 1990 and 1997. In all environments, possibly the greatest threat to productivity is disease, especially those caused by fungal pathogens. International wheat breeding has placed great emphasis on genetic control of disease since resource-poor farmers generally lack the means to control diseases chemically.

scholarly journals Molecular Cytogenetic Identification of a New Wheat-Rye 6R Chromosome Disomic Addition Line with Powdery Mildew Resistance

PLoS ONE ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. e0134534 ◽  
Author(s):  
Diaoguo An ◽  
Qi Zheng ◽  
Qiaoling Luo ◽  
Pengtao Ma ◽  
Hongxia Zhang ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Addition Line ◽  
Mildew Resistance ◽  
Disomic Addition Line ◽  
Molecular Cytogenetic

scholarly journals Discovery of powdery mildew resistance gene candidates from Aegilops biuncialis chromosome 2Mb based on transcriptome sequencing

2019 ◽  
Author(s):  
Huanhuan Li ◽  
Zhenjie Dong ◽  
Chao Ma ◽  
Xiubin Tian ◽  
Zhiguo Xiang ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Disease Resistance ◽  
Powdery Mildew ◽  
Resistance Gene ◽  
Powdery Mildew Resistance ◽  
Disease Resistance Gene ◽  
R Genes ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance ◽  
Resistance Gene Candidates

AbstractPowdery mildew is one of the most widespread diseases of wheat. Breeding resistant varieties by utilization of resistance genes is considered as the most economic and effective method of controlling this disease. Previous study showed that the gene(s) at 2Mb in Chinese Spring (CS)-Aegilops biuncialis 2Mb disomic addition line TA7733 conferred high resistance to powdery mildew. In this study, 15 Bgt isolates prevalent in different regions of China were used to further test the resistance spectrum of TA7733. As a result, TA7733 was high resistance to all tested isolates, indicating that the gene(s) on chromosome 2Mb was broad-spectrum powdery mildew resistance. In order to mine resistance gene candidates and develop 2Mb-specific molecular markers to assist the transfer resistance gene(s) at chromosome 2Mb, RNA-seq of TA7733 and CS was conducted before and after Bgt-infection, generating a total of 158,953 unigenes. Of which, 7,278 unigenes were TA7733-specific which were not expressed in CS, and 295 out of these 7,278 unigenes were annotated as R genes. Based on Blastn against with CS Ref Seq v1.0, 61 R genes were further mapped to homoeologous group 2. Analysis of R gene-specific molecular markers designed from R gene sequences verified 40 out of 61 R genes to be 2Mb specific. Annotation of these 40 R genes showed most genes encoded nucleotide binding leucine rich repeat (NLR) protein, being most likely resistance gene candidates. The broad-spectrum powdery mildew resistance gene(s), disease resistance gene candidates, and functional molecular markers of 2Mb-specific in present study will not only lay foundations for transferring disease resistance gene(s) from 2Mb to common wheat by inducing CS-Ae. biuncialis homoeologous recombination, but also provide useful candidates for isolating and cloning resistance gene(s) and dissecting molecular and genetic mechanisms of disease resistance from 2Mb.

Characterization of PmHHXM, a New Broad-spectrum Powdery Mildew Resistance Gene in Chinese Wheat Landrace Honghuaxiaomai

Plant Disease ◽  
2021 ◽  
Author(s):  
Shulin Xue ◽  
Mingxue Lu ◽  
Shanshan Hu ◽  
Hongxing Xu ◽  
Yuyu Ma ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Resistance Gene ◽  
Broad Spectrum ◽  
Powdery Mildew Resistance ◽  
Dominant Gene ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance ◽  
Wheat Landrace ◽  
Chinese Wheat

Powdery mildew, caused by fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is one of agronomically important and widespread wheat diseases causing severe yield losses. Deployment of broad‐spectrum disease-resistance genes is the preferred strategy to prevent this pathogen. Chinese wheat landrace Honghuaxiaomai (HHXM) was resistant to all 23 tested Bgt isolates at the seedling stage. The F1, F2, and F2:3 progenies derived from the cross HHXM × Yangmai 158 were used in this study, and genetic analysis revealed that a single dominant gene, designated as PmHHXM, conferred resistance to Bgt isolate E09. Bulked segregant analysis and molecular mapping initially located PmHHXM to the distal region of chromosome 4AL. To fine map PmHHXM, two critical recombinants were identified from 592 F2 plants and delimited PmHHXM to a 0.18-cM Xkasp475200–Xhnu552 interval covering 1.77-Mb, in which a number of disease resistance-related gene clusters were annotated. Comparative mapping of this interval revealed a perturbed synteny among Triticeae species. This study reports the new powdery mildew resistance gene PmHHXM that seems different from three known QTL/genes identified on chromosome 4AL and has significant values for further genetic improvement. Analysis of the polymorphisms of 13 co-segregating markers between HHXM and 170 modern wheat cultivars indicates that Xhnu227 and Xsts478700 developed here are ideal for marker-assisted introgression of this resistance gene in wheat breeding.

scholarly journals Development of Novel Wheat-Rye Chromosome 4R Translocations and Assignment of Their Powdery Mildew Resistance

Plant Disease ◽  
2020 ◽  
Vol 104 (1) ◽  
pp. 260-268 ◽  
Author(s):  
Pengtao Ma ◽  
Guohao Han ◽  
Qi Zheng ◽  
Shiyu Liu ◽  
Fangpu Han ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Common Wheat ◽  
Powdery Mildew Resistance ◽  
Translocation Line ◽  
Growth Stages ◽  
Alien Chromosome ◽  
Mildew Resistance ◽  
Wheat Improvement ◽  
Chromosome Arm

Rye (Secale cereale L.) is an important gene donor for wheat improvement because of its many valuable traits, especially disease resistance. Development of novel wheat-rye translocations with disease resistance can contribute to transferring resistance into common wheat. In a previous study, a wheat-rye T4BL·4RL and T7AS·4RS translocation line (WR41-1) was developed by distant hybridization, and it was speculated that its resistance to powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), was derived from rye based on pedigree analysis. To make accurate use of chromosome 4R in wheat improvement, a set of new 4R translocations involving different arm translocations (e.g., 4RS monosomic, 4RL monosomic, 4RL disomic, 4RS monosomic plus 4RL monosomic, 4RS monosomic plus 4RL disomic, and 4RS disomic plus 4RL disomic translocations) was developed from crosses with common wheat. Those translocations were characterized by genomic in situ hybridization and expressed sequence tag simple sequence repeat marker analysis. To confirm the source of powdery mildew resistance, the translocation plants were tested against Bgt isolate E09. The results indicated that all translocations with 4RL were resistant at all tested growth stages, whereas those with only 4RS translocation or no alien translocation were susceptible. This further indicated that the powdery mildew resistance of WR41-1 was derived from the alien chromosome arm 4RL. To effectively use 4RL resistance in wheat improvement, two competitive allele-specific PCR markers specific for chromosome arm 4RL were developed to detect the alien chromosome in the wheat genome. These new translocation lines with diagnostic markers can efficiently serve as important bridges for wheat improvement.

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