scholarly journals First Report of a New Wheat Leaf Rust (Puccinia triticina) Race with Virulence for Lr12, 13, and 37 in South Africa

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 611-611 ◽  
Author(s):  
T. Terefe ◽  
Z. A. Pretorius ◽  
C. M. Bender ◽  
B. Visser ◽  
L. Herselman ◽  
...  
Keyword(s):  
South Africa ◽  
Leaf Rust ◽  
South African ◽  
Adult Plant Resistance ◽  
Flag Leaf ◽  
Puccinia Triticina ◽  
Adult Plant ◽  
Western Cape ◽  
Wheat Leaf ◽  
New Race

A new race of Puccinia triticina was collected from common wheat (Triticum aestivum) in the Eastern and Western Cape provinces during the annual rust survey in 2009. Six single-pustule isolates from a field collection, which were shown to be a new race in preliminary analyses, were inoculated onto seedlings of 16 Thatcher (Tc) near-isogenic differential lines (1) and other tester lines with known Lr genes. Standard procedures for inoculation, incubation, and rust evaluation were followed (4) and all infection studies were repeated. The low infection type of Lr18 was confirmed at 18°C. All six isolates were avirulent (infection types [ITs] 0; to 2) to Lr1, 2a, 2c, 9, 11, 16, 18, and 24 and virulent (ITs 3 to 4) to Lr3, 3ka, 10, 14a, 17, 26, 30, B, and Tc (control). The new race, named 3SA145 according to the ARC-Small Grain Institute notation, corresponds to race CCPS in the North American system (1). On the basis of seedling ITs of the extended Lr gene set, 3SA145 was avirulent (ITs 0; to 22+) to Lr2b, 19, 21, 23, 25, 28, 29, 32, 36 (E84081), 38, 45, 47 (KS90H450), 50 (KS96WGRC36), 51 (R05), and 52 and virulent to Lr3bg, 15, 20 (Thew), 27+31 (Gatcher), and 33. Lines containing the adult plant resistance (APR) genes Lr12 (RL6011, IT 3++), Lr13 (CT263, IT 3), Lr22b (Tc, IT 4), and Lr37 (RL6081, IT 3) were susceptible in the adult stage to 3SA145, whereas lines with the APR genes Lr22a (RL6044, IT ;1), Lr34 (RL6058, IT Z1), and Lr35 (RL6082, IT ;1) were resistant in controlled infection studies in a greenhouse. A control, the common race (3SA133), was virulent only on Tc adult plants. In seedlings, 3SA133 was avirulent to Lr15, 17, 26, and 27+31, but unlike 3SA145, it was virulent to Lr1, 2c, 11, 18, 24, and 28. Races 3SA133 and 3SA145 did not differ in their virulence to the remaining seedling genes. Virulence to Lr37 has been reported in several countries, including Australia, Canada, Uruguay, and the United States (1,2). Prior to the detection of 3SA145, adult plants of RL6081 were resistant to all wheat leaf rust races in South Africa. In 2009, however, RL6081 showed severity levels of up to 30S at certain Western Cape trap plot sites. Of 124 South African bread wheat cultivars and advanced breeding lines tested at the seedling stage, 3SA145 was virulent to 48, whereas 3SA133 was virulent to 36 entries. A further six entries were heterogeneous in their reaction to 3SA145. In adult plant infection studies of 48 South African spring wheats in a greenhouse, 19 were susceptible (flag leaf IT ≥3) and 22 were resistant to 3SA145. Seven entries showed a Z3 flag leaf IT indicating adult plant resistance. According to a simple sequence repeat (SSR) study using 17 primer-pair combinations described by Szabo and Kolmer (3), 3SA145 showed 30% homology with the dominant South African races. Although virulence to Lr12 and Lr13 has been known in different leaf rust races in South Africa, to our knowledge, this is the first report of combined virulence to Lr12, 13, and 37. The SSR data and unique avirulence/virulence profile suggest that 3SA145 may be an exotic introduction to South Africa. References: (1) J. A. Kolmer et al. Plant Dis. 89:1201, 2005. (2) B. McCallum and P. Seto-Goh. Can. J. Plant Pathol. 31:80, 2009. (3) L. Szabo and J. Kolmer. Mol. Ecol. Notes 7:708, 2007. (4) T. Terefe et al. S. Afr. J. Plant Soil 26:51, 2009.

scholarly journals First Report of Virulence for the Wheat Leaf Rust (Puccinia triticina) Resistance Gene Lr32 in South Africa

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 381-381 ◽  
Author(s):  
Z. A. Pretorius ◽  
C. M. Bender
Keyword(s):  
South Africa ◽  
Leaf Rust ◽  
Resistance Gene ◽  
South African ◽  
Bread Wheat ◽  
Puccinia Triticina ◽  
The United States ◽  
Current Evidence ◽  
Wheat Leaf Rust ◽  
Wheat Leaf

The wheat leaf rust resistance gene Lr32 was transferred from Aegilops tauschii Coss. to bread wheat (Triticum aestivum L.) (1). Despite virulence for Lr32 in some isolates from Bulgaria, Israel, and Turkey, the gene has been reported to be effective in Australia, Mexico, the United States, and South Africa (1,2). A leaf rust isolate that differed in its avirulence/virulence profile from previously recorded races of Puccinia triticina Eriks. in South Africa was collected from triticale (× Triticosecale) in the Western Cape in 2005. According to the South African leaf rust differential set (3), this isolate (UVPt19) was avirulent for Lr3a, 3bg, 3ka, 10, 11, 16, 20, 26, and 30 and virulent for Lr1, 2a, 2b, 2c, 14a, 15, 17, 24, and Thatcher (Tc, control). Except for Lr20 in cv. Thew, all differentials are Tc near-isogenic lines. In comparison with known South African races (3), it differed from race 3SA132 at the Lr10 locus. Using standard rust pathology protocols (3), an expanded set of Lr gene lines (non Tc lines indicated) showed that UVPt19 is avirulent on wheat seedlings containing Lr9, 19, 21, 25, 27+31 (Gatcher), 29, 36 (ER84018), 37, 41 (KS91WGRC10), 44, 45, 47 (KS90H450), 50 (KS96WGRC36), 51 (R05), and 52, and virulent for Lr12, 22a, 23, 28, 32, 33, and 35. In the seedling stage, UVPt19 was virulent for the temperature sensitive genes Lr13, 18, and 34 at 25°C, but produced lower infection types (ITs) on Lr18 and 34 at 14 to 18°C. Seedlings of Pavon 76 (Lr46) were resistant (IT ;1=) to UVPt19. The susceptible response of lines carrying Lr32 was confirmed by high ITs (3++4) on RL5713/2*Mq, RL6086 (TcLr32), and RL5713/2*Mq//6*Palmiet. A control isolate (UVPt9) produced ITs ;1+, ;1+, and ;;1= on these lines, respectively. UVPt19 was virulent on line RL6092 (TcLr20) but avirulent on Thew. When tested on adult plants of lines RL6011 (TcLr12), CT263 (TcLr13), RL6044 (TcLr22a), RL6058 (TcLr34), RL6082 (TcLr35), RL6081 (TcLr37), and Tc (control), UVPt19 was only virulent (IT 3+) on CT263 and Tc. Flag leaves of RL6011 (IT ;1), RL6044 (IT 1), RL6058 (IT Z3-), RL6082 (IT 0;), and RL6081 (IT ;1) were resistant. UVPt19 was virulent on seedlings of 11 of 13 triticale cultivars and lines tested as opposed to UVPt9, which was virulent to only one entry. From a collection of 105 South African bread wheat cultivars and elite breeding lines, UVPt19 was virulent on 13 and five were mixed in their response to this isolate. All IT experiments were repeated. Although virulence has emerged for Lr32 in South Africa, the gene has not been used in local cultivars. Previously, McIntosh et al. (1) also reported that Lr32 has not been exploited in wheat production. On the basis of current evidence, UVPt19 appears to be potentially more damaging to triticale than bread wheat. Furthermore, the race seems rare because it was not collected in a recent wheat leaf rust survey in South Africa (3). References: (1) R. A. McIntosh et al. The Wheat Rusts: An Atlas of Resistance Genes, CSIRO-Kluwer, Dordrecht, the Netherlands, 1995. (2) Z. A. Pretorius. Phytophylactica 21:195, 1989. (3) T. Tarekegn et al. S. Afr. J. Plant Soil 26:51, 2009.

ADULT PLANT RESISTANCE IN WHEAT TO PHYSIOLOGIC RACES OF PUCCINIA TRITICINA ERIKSS.

1943 ◽  
Vol 21c (1) ◽  
pp. 10-17 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson
Keyword(s):  
Leaf Rust ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Puccinia Triticina ◽  
Seedling Stage ◽  
Adult Plant ◽  
Wheat Varieties ◽  
Physiologic Races ◽  
Two Stages ◽  
Derivatives Of

Nine wheat varieties were studied in two stages of growth, the seedling stage and the heading stage, for their reaction to a number of physiologic races of leaf rust of wheat, Puccinia triticina Erikss. Several varieties susceptible to certain physiologic races in the seedling stage were found to acquire, as they grew to maturity, a resistance to these races. In the adult plant, the resistance was greatest in the uppermost leaves but diminished progressively on lower leaves. The varieties tested fell into three groups on the basis of their rust reaction. (1) Renown and Regent, which developed adult plant resistance to all of the 19 races to which they were tested. In these two varieties, and possibly in other derivatives of H-44 and Hope, adult plant resistance to physiologic races of leaf rust may be a generalized phenomenon comparable to the resistance such varieties show towards stem rust. (2) Thatcher, Apex, Marquis, Reward, and Kenya R.L. 1373, which showed adult plant resistance only to certain physiologic races, a condition not hitherto encountered in other cereal rusts. (3) McMurachy and Warden × Hybrid, each of which reacted somewhat similarly in the seedling and heading stages, the former being susceptible and the latter resistant in both stages.

scholarly journals Genetic diversity in Puccinia triticina causing wheat leaf rust in South Africa

2015 ◽  
Vol 98 ◽  
pp. 204
Author(s):  
B. Visser ◽  
T.I. Selinga ◽  
T.G. Terefe ◽  
L. Herselman ◽  
Z.A. Pretorius
Keyword(s):  
South Africa ◽  
Genetic Diversity ◽  
Leaf Rust ◽  
Puccinia Triticina ◽  
Wheat Leaf Rust ◽  
Wheat Leaf

Characterization of genetic loci conferring adult plant resistance to leaf rust and stripe rust in spring wheat

Genome ◽  
2006 ◽  
Vol 49 (8) ◽  
pp. 977-990 ◽  
Author(s):  
H M William ◽  
R P Singh ◽  
J Huerta-Espino ◽  
G Palacios ◽  
K Suenaga
Keyword(s):  
Leaf Rust ◽  
Stripe Rust ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Puccinia Striiformis ◽  
Bulked Segregant Analysis ◽  
Puccinia Triticina ◽  
Adult Plant ◽  
Single Chromosome ◽  
Slow Rusting

Leaf (brown) and stripe (yellow) rusts, caused by Puccinia triticina and Puccinia striiformis, respectively, are fungal diseases of wheat (Triticum aestivum) that cause significant yield losses annually in many wheat-growing regions of the world. The objectives of our study were to characterize genetic loci associated with resistance to leaf and stripe rusts using molecular markers in a population derived from a cross between the rust-susceptible cultivar 'Avocet S' and the resistant cultivar 'Pavon76'. Using bulked segregant analysis and partial linkage mapping with AFLPs, SSRs and RFLPs, we identified 6 independent loci that contributed to slow rusting or adult plant resistance (APR) to the 2 rust diseases. Using marker information available from existing linkage maps, we have identified additional markers associated with resistance to these 2 diseases and established several linkage groups in the 'Avocet S' × 'Pavon76' population. The putative loci identified on chromosomes 1BL, 4BL, and 6AL influenced resistance to both stripe and leaf rust. The loci on chromosomes 3BS and 6BL had significant effects only on stripe rust, whereas another locus, characterized by AFLP markers, had minor effects on leaf rust only. Data derived from Interval mapping indicated that the loci identified explained 53% of the total phenotypic variation (R2) for stripe rust and 57% for leaf rust averaged across 3 sets of field data. A single chromosome recombinant line population segregating for chromosome 1B was used to map Lr46/Yr29 as a single Mendelian locus. Characterization of slow-rusting genes for leaf and stripe rust in improved wheat germplasm would enable wheat breeders to combine these additional loci with known slow-rusting loci to generate wheat cultivars with higher levels of slow-rusting resistance.Key words: Puccinia triticina, Puccinia striiformis, Triticum aestivum, bulked segregant analysis, single chromosome recombinant lines, linkage mapping, adult plant resistance.

scholarly journals Physiologic Specialization of Puccinia triticina in Canada in 1997

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 194-197 ◽  
Author(s):  
J. A. Kolmer
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Puccinia Triticina ◽  
Adult Plant ◽  
Western Canada ◽  
Summer Temperatures ◽  
Lower Infection ◽  
Infection Types

In 1997, 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, Saskatchewan, and Alberta. The leaf rust epidemic of 1997 was the most widespread and severe in western Canada since 1991. The Canada Prairie Spring wheat cultivars (AC Vista, AC Foremost, AC Crystal) were susceptible to leaf rust, while the bread wheats (AC Domain, AC Barrie, AC Cora, AC Majestic) were more resistant. Forty-seven virulence phenotypes of leaf rust were described in 1997 using 16 near-isogenic differential lines of Thatcher wheat. Phenotypes with virulence to Lr16 comprised 16% of the isolates in Manitoba and Saskatchewan in 1997. Many recently released Canadian spring wheats have Lr16 in addition to adult plant resistance genes. Thirty-three isolates also were tested for virulence to plants with adult plant resistance genes Lr12, Lr13, Lr34, and Lr13,34. Most isolates were virulent to genes Lr12 and Lr13. All isolates had lower infection types on lines with Lr34 compared with the susceptible line Thatcher.

scholarly journals Genetic Analysis of Adult-Plant Resistance to Leaf Rust in Five Spring Wheat Genotypes

Plant Disease ◽  
2003 ◽  
Vol 87 (12) ◽  
pp. 1522-1529 ◽  
Author(s):  
A. Navabi ◽  
R. P. Singh ◽  
J. P. Tewari ◽  
K. G. Briggs
Keyword(s):  
Leaf Rust ◽  
Plant Resistance ◽  
Combining Ability ◽  
Adult Plant Resistance ◽  
Puccinia Triticina ◽  
Diallel Cross ◽  
Transgressive Segregation ◽  
Adult Plant ◽  
Narrow Sense Heritability ◽  
Resistant Parent

Inheritance of adult-plant resistance to leaf rust, caused by Puccinia triticina, was studied in the progeny of a one-way diallel cross involving five CIMMYT-derived adult-plant resistant wheat (Triticum aestivum) genotypes and a susceptible wheat ‘Avocet-YrA’. F1 progenies, F2 populations, F2-derived F3, and F4-derived F5 lines were field evaluated under artificial epidemics with leaf rust race MCJ/SP. Adult-plant resistance to leaf rust was incompletely dominant in crosses with the susceptible parent and was found to be controlled by additive interactions of Lr34 with at least two to three additional genes. Transgressive segregation giving rise to plants or lines with higher and lower levels of resistance than the parents was observed in all F2 and F5 derivatives of the resistant-parent intercrosses and suggested that, apart from Lr34, some of the other additive genes were nonallelic. Although specific combining ability was significant in some generations, general combining ability was found to be the major component of variation. Among generations, the estimates of the narrow-sense heritability of adult-plant resistance to leaf rust ranged from 0.67 to 0.97.

scholarly journals First Detection of Virulence in Puccinia triticina to Resistance Genes Lr27 + Lr31 Present in Durum Wheat in Mexico

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 110-110 ◽  
Author(s):  
J. Huerta-Espino ◽  
R. P. Singh ◽  
S. A. Herrera-Foessel ◽  
J. B. Pérez-López ◽  
P. Figueroa-López
Keyword(s):  
Durum Wheat ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Triticum Turgidum ◽  
Puccinia Triticina ◽  
The State ◽  
Adult Plant ◽  
Adult Plant Resistance Gene ◽  
New Race ◽  
Plant Resistance Gene

Leaf rust caused by Puccinia triticina Eriks. was observed during the 2007–2008 crop season in the state of Sonora, Mexico on previously resistant durum wheat (Triticum turgidum L.) cvs. Jupare C2001 (Lr27 + 31) and Banamichi C2004. Single uredinial isolates were made from disease samples collected in the field and tested mostly on ‘Thatcher’ differentials at seedling or adult-plant stages (1). The isolates were identified as a new race, BBG/BP, resembling race BBG/BN predominant on durum wheat (2), but with additional virulences to resistance genes Lr27 + Lr31 in Gatcher and adult-plant resistance gene Lr12. The new race was also identified in samples collected from durum wheat in the State of Nuevo Leon during the same season. The avirulence/virulence formula of race BBG/BP is Lr1, 2a, 2b, 2c, 3, 3ka, 3bg, 9, 13, 14a, 15, 16, 17, 18, 19, 21, 22a, 24, 25, 26, 28, 29, 30, 32, 35, 37/Lr10, 11, 12, 14b, 20, 23, 27 + 31, 33. Although virulences to Lr27 + Lr31 and Lr12 is known to occur in P. triticina races predominant on bread wheat (T. aestivum L.) (1), to our knowledge, this is the first report of such virulences in the pathogen population on durum wheat. Pure isolates of race BBG/BP are stored in the CIMMYT leaf rust collection. References: (1) R. P. Singh. Plant Dis. 75:790, 1991. (2) R. P. Singh et al. Plant Dis. 88:703, 2004.

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