scholarly journals Cytogenetic analysis and mapping of leaf rust resistance in Aegilops speltoides Tausch derived bread wheat line Selection2427 carrying putative gametocidal gene(s)

Genome ◽  
2017 ◽  
Vol 60 (12) ◽  
pp. 1076-1085 ◽  
Author(s):  
M. Niranjana ◽  
Vinod ◽  
J.B. Sharma ◽  
Niharika Mallick ◽  
S.M.S. Tomar ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Bread Wheat ◽  
Rust Resistance ◽  
Dominant Gene ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Aegilops Speltoides ◽  
Lr Genes ◽  
Gametocidal Gene ◽  
Chromosome 3B

Leaf rust (Puccinia triticina) is a major biotic stress affecting wheat yields worldwide. Host-plant resistance is the best method for controlling leaf rust. Aegilops speltoides is a good source of resistance against wheat rusts. To date, five Lr genes, Lr28, Lr35, Lr36, Lr47, and Lr51, have been transferred from Ae. speltoides to bread wheat. In Selection2427, a bread wheat introgresed line with Ae. speltoides as the donor parent, a dominant gene for leaf rust resistance was mapped to the long arm of chromosome 3B (LrS2427). None of the Lr genes introgressed from Ae. speltoides have been mapped to chromosome 3B. Since none of the designated seedling leaf rust resistance genes have been located on chromosome 3B, LrS2427 seems to be a novel gene. Selection2427 showed a unique property typical of gametocidal genes, that when crossed to other bread wheat cultivars, the F1 showed partial pollen sterility and poor seed setting, whilst Selection2427 showed reasonable male and female fertility. Accidental co-transfer of gametocidal genes with LrS2427 may have occurred in Selection2427. Though LrS2427 did not show any segregation distortion and assorted independently of putative gametocidal gene(s), its utilization will be difficult due to the selfish behavior of gametocidal genes.

Transfer to hexaploid wheat of linked genes for adult-plant leaf rust and seedling stem rust resistance from an amphiploid of Aegilops speltoides × Triticum monococcum

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 530-537 ◽  
Author(s):  
E. R. Kerber ◽  
P. L. Dyck
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Dominant Gene ◽  
Leaf Rust Resistance ◽  
Stem Rust Resistance ◽  
Adult Plant ◽  
Aegilops Speltoides ◽  
Plant Leaf

A partially dominant gene for adult-plant leaf rust resistance together with a linked, partially dominant gene for stem rust resistance were transferred to the hexaploid wheat cultivar 'Marquis' from an amphiploid of Aegilops speltoides × Triticum monococcum by direct crossing and backcrossing. Pathological evidence indicated that the alien resistance genes were derived from Ae. speltoides. Differential transmission of the resistance genes through the male gametes occurred in hexaploid hybrids involving the resistant 'Marquis' stock and resulted in distorted segregation ratios. In heterozygotes, pairing between the chromosome arm with the alien segment and the corresponding arm of the normal wheat chromosome was greatly reduced. The apparent close linkage between the two resistance genes, 3 ± 1.07 crossover units, was misleading because of this decrease in pairing in the presence of the 5B diploidizing mechanism. The newly identified gene for adult-plant leaf rust resistance, located on chromosome 2B, is different from adult-plant resistance genes Lr12, Lr13, and Lr22 and from that in the hexaploid accession PI250413; it has been designated Lr35. It is not known whether the newly transferred gene for stem rust resistance differs from Sr32, also derived from Ae. speltoides and located on chromosomes 2B.Key words: hexaploid, Triticum, Aegilops, aneuploid, Puccinia graminis, Puccinia recondita.

scholarly journals Genetic analysis and molecular mapping of leaf rust resistance genes in the wheat line 5R618

2014 ◽  
Vol 50 (No. 4) ◽  
pp. 262-267 ◽  
Author(s):  
J. Wang ◽  
L. Shi ◽  
L. Zhu ◽  
X. Li ◽  
D. Liu
Keyword(s):  
Leaf Rust ◽  
Resistance Gene ◽  
Rust Resistance ◽  
Molecular Mapping ◽  
Dominant Gene ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Triticum Aestivum L ◽  
Rust Resistance Gene ◽  
Leaf Rust Resistance Gene

The wheat (Triticum aestivum L.) line 5R618, bred at the China Agricultural University, is resistant in the seedling stage to the majority of the current Chinese pathotypes of wheat leaf rust (Puccinia triticina). To identify and map the leaf rust resistance gene in the 5R618 line, F<sub>2</sub> plants and F<sub>2:3</sub> families from a cross between 5R618 and Zhengzhou5389 (susceptible) were inoculated in the greenhouse with the Chinese P. triticina pathotype THJP. Results from the F<sub>2</sub> and F<sub>2:3</sub> populations indicate that a single dominant gene, temporarily designated&nbsp;Lr5R, conferred resistance. Using the molecular marker method, Lr5R was located on the 3DL chromosome. It was closely linked to the markers Xbarc71 and OPJ-09 with genetic distances of 0.9 cM and 1.0 cM, respectively. At present only one designated gene (Lr24) is located on the 3DL chromosome. The genetic distance between Lr5R&nbsp;and Lr24 confirms that Lr5R is a new leaf rust resistance gene.

scholarly journals Identification of Leaf Rust Resistance Genes in Chinese Common Wheat Cultivars

Plant Disease ◽  
2017 ◽  
Vol 101 (10) ◽  
pp. 1729-1737 ◽  
Author(s):  
Takele Weldu Gebrewahid ◽  
Zhan-Jun Yao ◽  
Xiao-Cui Yan ◽  
Pu Gao ◽  
Zai-Feng Li
Keyword(s):  
Leaf Rust ◽  
Common Wheat ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Field Tests ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Wheat Cultivars ◽  
Lr Genes

Puccinia triticina Eriks. (Pt), the causal agent of wheat (Triticum aestivum L.) leaf rust, is the most widespread disease of common wheat worldwide. In the present study, 83 wheat cultivars from three provinces of China and 36 tester lines with known leaf rust resistance (Lr) genes were inoculated in the greenhouse with 18 Pt pathotypes to identify seedling effective Lr genes. Field tests were also performed to characterize slow leaf rusting responses at the adult plant growth stage in Baoding and Zhoukou in the 2014–15 and 2015–16 cropping seasons. Twelve Lr genes, viz. Lr1, Lr26, Lr3ka, Lr11, Lr10, Lr2b, Lr13, Lr21, Lr34, Lr37, Lr44, and Lr46 either singly or in combination were identified in 41 cultivars. Known Lr genes were not detected in the remaining 42 cultivars. The most commonly identified resistance genes were Lr26 (20 cultivars), Lr46 (18 cultivars), and Lr1 (eight cultivars). Less frequently detected genes included Lr13, Lr34, and Lr37 (each present in four cultivars), Lr10 (three cultivars), and Lr3ka and Lr44 (each in two cultivars). Evidence for the presence of genes Lr11, Lr2b, and Lr21 (each in one cultivar) was also obtained. Seventeen cultivars were found to have slow rusting resistance in both field growing seasons.

scholarly journals Physiologic Specialization of Puccinia triticina in Canada in 1998

Plant Disease ◽  
2001 ◽  
Vol 85 (2) ◽  
pp. 155-158 ◽  
Author(s):  
J. A. Kolmer
Keyword(s):  
Leaf Rust ◽  
Bread Wheat ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Wheat Cultivars ◽  
Rust Resistance Genes ◽  
Leaf Rust Resistance Genes

In 1998, leaf rust of wheat (Triticum aestivum), caused by Puccinia triticina, was widespread throughout the prairies of western Canada. Warm summer temperatures with frequent dew periods favored spread of the disease in wheat fields in Manitoba and Saskatchewan. The Canada Prairie Spring wheat cultivars (AC Vista, AC Foremost, AC Crystal) were susceptible to leaf rust, while the bread wheat cultivars with leaf rust resistance genes Lr16 and Lr13 or Lr34 (AC Majestic, AC Domain, AC Barrie) had high to moderate levels of leaf rust infections. Bread wheat cultivars AC Cora, AC Minto, Pasqua, and McKenzie had trace to low levels of leaf rust infection. Thirty-four virulence phenotypes of P. triticina were identified on 16 Thatcher lines, which are near-isogenic for leaf rust resistance genes. Phenotypes with virulence to Lr16 increased to 25% of isolates in Manitoba and Saskatchewan in 1998. Forty-three isolates were also tested for virulence to plants with the adult plant resistance genes Lr12, Lr13, Lr34, and Lr13,34. Most isolates had virulence to Lr12 and Lr13. All isolates had lower infection type on adult plants with Lr34 compared with Thatcher.

scholarly journals Whole-genome sequencing of multiple isolates of Puccinia triticina reveals asexual lineages evolving by recurrent mutations

2020 ◽  
Author(s):  
John P. Fellers ◽  
Sharadha Sakthikumar ◽  
Fei He ◽  
Katie McRell ◽  
Guus Bakkeren ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Rust Resistance ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Whole Genome Sequence ◽  
Bootstrap Support ◽  
Aegilops Speltoides ◽  
Whole Genome ◽  
Synonymous Mutations ◽  
Recurrent Mutations

ABSTRACTBackgroundThe wheat leaf rust fungus, Puccinia triticina Erikss. is a worldwide pathogen of tetraploid durum and hexaploid wheat. Many races of P. triticina differ for virulence to specific leaf rust resistance genes and are found in most wheat-growing regions of the world. Wheat cultivars with effective leaf rust resistance exert selection pressure on P. triticina populations for virulent race types. The objectives of this study were to examine whole-genome sequence data of 121 P. triticina isolates and to gain insight into race evolution. The collection included isolates comprising many different race phenotypes collected worldwide from common wheat in the U.S. and the European Union together with isolates from durum wheat. One isolate from the wild wheat relative Aegilops speltoides, and two from Ae. cylindrica were also included for comparison.ResultsBased on 121,907 variants identified relative to the reference race 1-1 genome, the isolates were clustered into 11 major lineages with 100% bootstrap support. The isolates were also grouped based on variation in approximately 1400 secreted resistance interactor candidate proteins. In gene-coding regions, all groups had high ratios of non-synonymous to synonymous mutations and nonsense to readthrough mutations.ConclusionsBased on total variation or variation in the secreted protein genes, isolates grouped the same indicating that variants were distributed across the entire genome. Our results suggest that recurrent mutation and selection play a major role in differentiation within the clonal lineages.

scholarly journals Non-hypersensitive leaf rust resistance of bread wheat cultivar PBW65 conditioned by genes different fromLr34

2009 ◽  
Vol 45 (No. 1) ◽  
pp. 26-30 ◽  
Author(s):  
M.A. Khan ◽  
R.G. Saini
Keyword(s):  
Leaf Rust ◽  
Bread Wheat ◽  
Rust Resistance ◽  
Wheat Cultivar ◽  
Infection Type ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Triticum Aestivum L ◽  
Resistance Level ◽  
Highly Virulent

: The bread wheat (Triticum aestivum L.) cultivar PBW65 has shown hight levels of resistance to the most frequent and highly virulent Indian race 77-5 of leaf rust (Puccinia triticina). The infection type and disease severity indicated a non-hypersensitive type of resistance against the race 77-5 in PBW65. The cultivar PBW65 was crossed with the leaf rust susceptible cultivar WL711 to determine the mode of inheritance of the resistance. The segregation for resistant and susceptible plants in the F<sub>2</sub> and F<sub>3</sub> generations revealed, that two genes, each showing additive effects, were likely to confer resistance to leaf rust in PBW65. Intercrossing of PBW65 with Cook (Lr34), RL6058 (Lr34) and HD2009, possessing a similar resistance level like PBW65, revealed that the genes for leaf rust resistance in PBW65 were non-allelic to Cook (Lr34), RL6058 (Lr34) as well as to the gene(s) in HD2009. It is concluded that the cultivar PBW65 is a novel source of non-hypersensitive leaf rust resistance.

scholarly journals Map-Based Cloning of Leaf Rust Resistance Gene Lr21 From the Large and Polyploid Genome of Bread Wheat

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 655-664 ◽  
Author(s):  
Li Huang ◽  
Steven A Brooks ◽  
Wanlong Li ◽  
John P Fellers ◽  
Harold N Trick ◽  
...  
Keyword(s):  
Amino Acid ◽  
Leaf Rust ◽  
Resistance Gene ◽  
Bread Wheat ◽  
Rust Resistance ◽  
Agronomic Traits ◽  
Leaf Rust Resistance ◽  
Triticum Aestivum L ◽  
Rust Resistance Gene ◽  
Leaf Rust Resistance Gene

Abstract We report the map-based cloning of the leaf rust resistance gene Lr21, previously mapped to a generich region at the distal end of chromosome arm 1DS of bread wheat (Triticum aestivum L.). Molecular cloning of Lr21 was facilitated by diploid/polyploid shuttle mapping strategy. Cloning of Lr21 was confirmed by genetic transformation and by a stably inherited resistance phenotype in transgenic plants. Lr21 spans 4318 bp and encodes a 1080-amino-acid protein containing a conserved nucleotide-binding site (NBS) domain, 13 imperfect leucine-rich repeats (LRRs), and a unique 151-amino-acid sequence missing from known NBS-LRR proteins at the N terminus. Fine-structure genetic analysis at the Lr21 locus detected a noncrossover (recombination without exchange of flanking markers) within a 1415-bp region resulting from either a gene conversion tract of at least 191 bp or a double crossover. The successful map-based cloning approach as demonstrated here now opens the door for cloning of many crop-specific agronomic traits located in the gene-rich regions of bread wheat.

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