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

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.

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 288-291 ◽  
Author(s):  
J. A. Kolmer

Collections of Puccinia triticina were made from rust-infected wheat leaves in Georgia, South Carolina, North Carolina, and Virginia in 1999 to examine if these states can be considered as a single epidemiological unit for virulence phenotypes of the wheat leaf rust pathogen. Singleuredinial isolates derived from the leaf rust collections were processed for identification of virulence phenotypes on seedling plants in greenhouse tests. Twenty-one virulence phenotypes from 253 isolates were described based on infection type to 16 Thatcher wheat lines near-isogenic for leaf rust resistance genes. Virulence phenotype MBRK (virulent to leaf rust resistance genes Lr1, Lr3, Lr3ka, Lr11, Lr30, Lr10, Lr14a, and Lr18) was the most common phenotype in the region, at 38.7% of all isolates. Phenotype TLGF (virulent to Lr1, Lr2a, Lr2c, Lr3, Lr9, Lr11, Lr14a, and Lr18) was the second most common phenotype overall, at 33.8% of isolates. Twenty-nine isolates selected on the basis of seedling virulence phenotypes also were tested for virulence to adult wheat plants with the resistance genes Lr12, Lr13, Lr22b, and Lr34. In all, 23 isolates were avirulent to Lr12 and 26 isolates were virulent to Lr13. All isolates had fewer and smaller uredinia on the Thatcher line with Lr34 compared with Thatcher. The widespread occurrence of the predominant P. triticina virulence phenotypes throughout the region indicated that the South Atlantic states should be considered as a single epidemiological area for wheat leaf rust. Some virulence phenotypes which occurred at lower frequencies were found primarily in the Coastal Plain and mountains of North Carolina or in breeding plots in southern Georgia. Localized populations of P. triticina may develop in the South Atlantic region due to overwintering of leaf rust infections or specific selection by leaf rust resistance genes in wheat cultivars.


Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1601-1607 ◽  
Author(s):  
T. G. Liu ◽  
W. Q. Chen

Wheat leaf rust, caused by Puccinia triticina, is an important foliar disease of wheat in China. The dynamics of races and virulence in P. triticina populations in China during 2000 to 2006 were studied. Leaf rust samples were collected during surveys of wheat fields and trap nurseries in 16 provinces, and provided by coworkers throughout China. The virulence of single-pustule isolates was determined on near-isogenic Thatcher lines for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17, and Lr30, and races were denominated using the Prt code system. During 2000 to 2006, 79 races were identified from a total of 613 isolates. Races PHT (23.7%), THT (14.7%), PHJ (11.4%), and THJ (4.2%) were the four common races, all avirulent to Lr9 and Lr24. The frequency of isolates with virulence to Lr1, Lr2c, Lr3, Lr11, Lr16, Lr17, and Lr26 was over 80%, and these isolates were widely distributed in China, whereas the frequencies of virulence to Lr9, Lr19, Lr24, Lr25, Lr28, and Lr29 were 0.2 to 2.5%. The diversity of virulence phenotypes of Chinese P. triticina populations appeared to increase from 2000 to 2006. P. triticina races and virulences in China appear to be isolated from those in other countries.


2016 ◽  
Vol 106 (4) ◽  
pp. 380-385 ◽  
Author(s):  
J. A. Kolmer ◽  
M. A. Acevedo

Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from tetraploid and hexaploid wheat in the central highlands of Ethiopia, and a smaller number from Kenya, from 2011 to 2013, in order to determine the genetic diversity of this wheat pathogen in a center of host diversity. Single-uredinial isolates were derived and tested for virulence phenotype to 20 lines of Thatcher wheat that differ for single leaf rust resistance genes and for molecular genotypes with 10 simple sequence repeat (SSR) primers. Nine virulence phenotypes were described among the 193 isolates tested for virulence. Phenotype BBBQJ, found only in Ethiopia, was predominantly collected from tetraploid wheat. Phenotype EEEEE, also found only in Ethiopia, was exclusively collected from tetraploid wheat and was avirulent to the susceptible hexaploid wheat ‘Thatcher’. Phenotypes MBDSS and MCDSS, found in both Ethiopia and Kenya, were predominantly collected from common wheat. Phenotypes CCMSS, CCPSS, and CBMSS were found in Ethiopia from common wheat at low frequency. Phenotypes TCBSS and TCBSQ were found on durum wheat and common wheat in Kenya. Four groups of distinct SSR genotypes were described among the 48 isolates genotyped. Isolates with phenotypes BBBQJ and EEEEE were in two distinct SSR groups, and isolates with phenotypes MBDSS and MCDSS were in a third group. Isolates with CCMSS, CCPSS, CBMSS, TCBSS, and TCBSQ phenotypes were in a fourth SSR genotype group. The diverse host environment of Ethiopia has selected and maintained a genetically divergent population of P. triticina.


Genome ◽  
2017 ◽  
Vol 60 (12) ◽  
pp. 1076-1085 ◽  
Author(s):  
M. Niranjana ◽  
Vinod ◽  
J.B. Sharma ◽  
Niharika Mallick ◽  
S.M.S. Tomar ◽  
...  

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.


2014 ◽  
Vol 104 (12) ◽  
pp. 1322-1328 ◽  
Author(s):  
Alexander Loladze ◽  
Dhouha Kthiri ◽  
Curtis Pozniak ◽  
Karim Ammar

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.


Genome ◽  
1998 ◽  
Vol 41 (3) ◽  
pp. 328-336 ◽  
Author(s):  
Francesca Gallego ◽  
Catherine Feuillet ◽  
Monika Messmer ◽  
Anja Penger ◽  
Andreas Graner ◽  
...  

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 943
Author(s):  
Pakeerathan Kandiah ◽  
Mumta Chhetri ◽  
Matthew Hayden ◽  
Michael Ayliffe ◽  
Harbans Bariana ◽  
...  

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.


Genome ◽  
1998 ◽  
Vol 41 (3) ◽  
pp. 328-336 ◽  
Author(s):  
Francesca Gallego ◽  
Catherine Feuillet ◽  
Monika Messmer ◽  
Anja Penger ◽  
Andreas Graner ◽  
...  

The wheat genome is large, hexaploid, and contains a high amount of repetitive sequences. In order to isolate agronomically important genes from wheat by map-based cloning, a simpler model of the genome must be used for identifying candidate genes. The objective of this study was to comparatively map the genomic regions of two wheat leaf rust disease resistance loci, Lr1 and Lr10, in the putative model genomes of rice and barley. Two probes cosegregating with the Lr1 gene on chromosome 5DL of wheat were studied. The rice sequences corresponding to the two probes were isolated and mapped. The two probes mapped to two different rice chromosomes, indicating that the organization of the region orthologous to Lr1 is different in rice and wheat. In contrast, synteny was conserved between wheat and barley in this chromosomal region. The Lrk10 gene cosegregated with Lr10 on chromosome 1AS in wheat. The rice gene corresponding to Lrk10 was mapped on rice chromosome 1, where it occurred in many copies. This region on rice chromosome 1 corresponds to the distal part of the group 3S chromosomes in Triticeae. The synteny is conserved between rice chromosome 1 and the Triticeae group 3S chromosomes up to the telomere of the chromosomes. On group 3S chromosomes, we found a gene that is partially homologous to Lrk10. We conclude that in the genomic regions studied, there is limited and only partially useful synteny between wheat and rice. Therefore, barley should also be considered as a model genome for isolating the Lr1 and Lr10 genes from wheat.Key words: barley, comparative mapping, leaf rust, resistance genes, rice, synteny, wheat.


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