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

2021 ◽  
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 ◽  
Secreted Protein ◽  
Whole Genome ◽  
Synonymous Mutations ◽  
Recurrent Mutations

Abstract The 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 of many different race phenotypes collected worldwide from common and durum wheat. One isolate from wild wheat relative Aegilops speltoides and two from Ae. cylindrica were also included for comparison. Based on 121,907 informative variants identified relative to the reference Race 1-1 genome, isolates were clustered into 11 major lineages with 100% bootstrap support. The isolates were also grouped based on variation in 1311 predicted secreted protein genes. In gene-coding regions, all groups had high ratios of non-synonymous to synonymous mutations and nonsense to readthrough mutations. Grouping of isolates based on two main variation principle components for either genome wide variation or variation just within the secreted protein genes, indicated similar groupings. Variants were distributed across the entire genome, not just within the secreted protein genes. Our results suggest that recurrent mutation and selection play a major role in differentiation within the clonal lineages.

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.

scholarly journals Genetic Analysis of Leaf Rust Resistance in Six Durum Wheat Genotypes

2014 ◽  
Vol 104 (12) ◽  
pp. 1322-1328 ◽  
Author(s):  
Alexander Loladze ◽  
Dhouha Kthiri ◽  
Curtis Pozniak ◽  
Karim Ammar
Keyword(s):  
Durum Wheat ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Durable Resistance ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Allelism Tests

Leaf rust, caused by Puccinia triticina, is one of the main fungal diseases limiting durum wheat production. This study aimed to characterize previously undescribed genes for leaf rust resistance in durum wheat. Six different resistant durum genotypes were crossed to two susceptible International Maize and Wheat Improvement Center (CIMMYT) lines and the resulting F1, F2, and F3 progenies were evaluated for leaf rust reactions in the field and under greenhouse conditions. In addition, allelism tests were conducted. The results of the study indicated that most genotypes carried single effective dominant or recessive seedling resistance genes; the only exception to this was genotype Gaza, which carried one adult plant and one seedling resistance gene. In addition, it was concluded that the resistance genes identified in the current study were neither allelic to LrCamayo or Lr61, nor were they related to Lr3 or Lr14a, the genes that already are either ineffective or are considered to be vulnerable for breeding purposes. A complicated allelic or linkage relationship between the identified genes is discussed. The results of the study will be useful for breeding for durable resistance by creating polygenic complexes.

scholarly journals Mapping of Adult Plant Leaf Rust Resistance in Aus27506 and Validation of Underlying Loci by In-Planta Fungal Biomass Accumulation

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 943
Author(s):  
Pakeerathan Kandiah ◽  
Mumta Chhetri ◽  
Matthew Hayden ◽  
Michael Ayliffe ◽  
Harbans Bariana ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Rust Resistance ◽  
Green Revolution ◽  
Puccinia Triticina ◽  
Biomass Accumulation ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
In Planta ◽  
Plant Leaf ◽  
Ril Population

Among the rust diseases, leaf rust of wheat caused by Puccinia triticina, is the most prevalent worldwide and causes significant yield losses. This study aimed to determine the genomic location of loci that control adult plant resistance (APR) to leaf rust in the pre-Green Revolution landrace accession, Aus27506, from the “Watkins Collection”. An Aus27506/Aus27229-derived F7 recombinant inbred line (RIL) population was screened under field conditions across three cropping seasons and genotyped with the iSelect 90K Infinium SNP bead chip array. One quantitative trait loci (QTL) on each of the chromosomes 1BL, 2B and 2DL explained most of the leaf rust response variation in the RIL population, and these were named QLr.sun-1BL, QLr.sun-2B and QLr.sun-2DL, respectively. QLr.sun-1BL and QLr.sun-2DL were contributed by Aus27506. QLr.sun-1BL is likely Lr46, while QLr.sun-2DL appeared to be a new APR locus. The alternate parent, Aus27229, carried the putatively new APR locus QLr.sun-2B. The comparison of average severities among RILs carrying these QTL in different combinations indicated that QLr.sun-2B does not interact with either of the other two QTL; however, the combination of QLr.sun-1BL and QLr.sun-2DL reduced disease severity significantly. In planta fungal quantification assays validated these results. The RILs carrying QLr.sun-1BL and QLr.sun-2DL did not differ significantly from the parent Aus27506 in terms of resistance. Aus27506 can be used as a source of adult plant leaf rust resistance in breeding programs.

scholarly journals Virulence of Puccinia triticina on Wheat in Nebraska during 1997 and 1998

Plant Disease ◽  
2001 ◽  
Vol 85 (2) ◽  
pp. 159-164 ◽  
Author(s):  
J. E. Watkins ◽  
J. Schimelfenig ◽  
P. S. Baenziger ◽  
K. M. Eskridge
Keyword(s):  
Leaf Rust ◽  
Rust Resistance ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Wheat Leaf ◽  
Virulence Frequency ◽  
Made In

Urediniospore isolates of Puccinia triticina were obtained from wheat leaf collections made in three wheat-growing regions in Nebraska in 1997 and in four regions in 1998. Using 16 Thatcher lines that are near-isogenic for leaf rust resistance, 17 virulence phenotypes were found among 121 single uredinial isolates in 1997, and 42 virulence phenotypes were found among 178 isolates in 1998. The most prevalent phenotype in 1997 was MDRR (virulent on Lr1, 3, 3ka, 10, 11, 18, 23, 24, and 30). In 1998, virulence phenotypes MDRR and MDRM (virulent on Lr1, 3, 3ka, 10, 11, 23, 24, and 30) were the most prevalent. In both years, virulence frequency was above 80% to genes Lr1, 3, 3ka, 10, 11, 23, 24, and 30 and below 21% to Lr2a, 17, and 26. Virulence frequency to Lr2c was 37% in 1997 and 22% in 1998. No virulence was found to Lr9, 16, or 21 in either year. New virulence phenotypes were detected in 1998 that were not found in 1997. In 1998, virulence was less frequent on Lr2a, 2c, 3ka, 18, 24, and 26 and more frequent on Lr17 than in 1997.

Identification of a STS marker linked to the Aegilops speltoides-derived leaf rust resistance gene Lr28 in wheat

1998 ◽  
Vol 97 (4) ◽  
pp. 535-540 ◽  
Author(s):  
S. Naik ◽  
K. S. Gill ◽  
V. S. Prakasa Rao ◽  
V. S. Gupta ◽  
S. A. Tamhankar ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Resistance Gene ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Rust Resistance Gene ◽  
Aegilops Speltoides ◽  
Leaf Rust Resistance Gene ◽  
Sts Marker

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.

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