scholarly journals Identificação de fontes de resistência à ferrugem da folha do trigo em acessos de Aegilops tauschii

2007 ◽  
Vol 32 (4) ◽  
pp. 349-352 ◽  
Author(s):  
Ângela B. Almeida ◽  
Márcia S. Chaves ◽  
Sandra P. Brammer ◽  
Maria Irene Baggio

No Brasil, prejuízos ocasionados pela ferrugem da folha do trigo (Puccinia triticina) ocorrem anualmente. A incidência generalizada nas diferentes regiões produtoras varia em intensidade, dependendo das condições climáticas, da resistência genética das cultivares e do controle químico, sendo que a utilização de cultivares resistentes é o método mais eficiente de controle. Os genes que conferem resistência à ferrugem da folha em trigo são denominados Lr (leaf rust). Vários desses genes já foram identificados e mapeados. Alguns deles foram mapeados diretamente em genótipos hexaplóides, enquanto outros foram primeiramente encontrados em espécies afins, com menor nível de ploidia e, posteriormente, transferidos para o trigo cultivado. Das espécies afins, destaca-se a espécie diplóide Aegilops tauschii, doadora do genoma D do trigo cultivado, como uma importante fonte de genes de resistência. O objetivo desse trabalho foi avaliar a resistência à ferrugem da folha em acessos de Ae. tauschii, oriundos do Banco Ativo de Germoplasma da Embrapa Trigo (BAG - Passo Fundo, RS), para utilização das seleções nos programas de melhoramento. Quarenta acessos foram avaliados quanto à reação à raça SPJ-RS de Puccinia triticina e, destes, 25% (10 acessos) apresentaram resistência. Os dados obtidos neste estudo servem como subsídio na escolha de acessos resistentes que poderão ser utilizados como genitores em programas de melhoramento genético a fim de incremento de resistência a esse patógeno.

2018 ◽  
Vol 9 ◽  
Author(s):  
Maciej Majka ◽  
Albrecht Serfling ◽  
Paweł Czembor ◽  
Aurelia Ślusarkiewicz-Jarzina ◽  
Michał Tomasz Kwiatek ◽  
...  

Author(s):  
G. V. Volkova ◽  
O. A. Kudinova ◽  
O. F. Vaganova

Currently, more than 70 wheat rust resistance genes are known, but few of them are effective. The purpose of this work is to screen lines of Lr gene carriers for resistance to leaf rust under conditions of the North Caucasus region. Investigations were carried out in 2016-2018 at the infectious site of VNIIBZR. Research material was 49 near isogenic lines of winter wheat cultivar Thatcher. Infectious material was the combined populations of P. triticina, obtained as a result of route surveys of industrial and breeding crops of winter wheat in the areas of the Krasnodar, Stavropol Territories and the Rostov Region, conducted in 2016-2018. According to the assessment, the genes are ranked as follows: - highly efficient genes (plants with no signs of damage): Lr9, Lr42, Lr43 + 24 and Lr50; effective (1R-5R) Lr genes: 19, 24, 29, 36, 37, 38, 45, 47; moderately effective (10MR-20MR) Lr genes: 17, 18, 21, 22a, 28, 32, 41, 52. The remaining Lr-lines were susceptible to P. triticina (25 MR - 90S) to varying degrees. Highly efficient and effective genes Lr9, Lr19, Lr24, Lr29, Lr38, Lr42, Lr43 + 24, Lr47 and Lr50 showed resistance in the seedling phase and can be recommended for inclusion in breeding programs to protect wheat from leaf rust in different phases of plant ontogenesis in the North Caucasus region.


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.


Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, and southeastern states in order to determine the virulence of the wheat leaf rust population in 2013. Single uredinial isolates (490 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2013, 79 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TNBGJ, and MCTNB were the three most common phenotypes. Phenotypes MBTNB and MCTNB are both virulent to Lr11, and MCTNB is virulent to Lr26. MBTNB and MCTNB were most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Isolates with virulence to Lr11, Lr18, and Lr26 were common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21, Lr24, and Lr39/41 were frequent in the hard red wheat region of the southern and northern Great Plains.


Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 979-984 ◽  
Author(s):  
J. A. Kolmer ◽  
D. L. Long ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected wheat leaves by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio River Valley, southeast, California, and Washington State, in order to determine the virulence of the wheat leaf rust population in 2005. Single uredinial isolates (797 in total) were derived from the collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3a, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr18, Lr21, Lr28, and winter wheat lines with genes Lr41 and Lr42. In the United States in 2005, 72 virulence phenotypes of P. triticina were found. Virulence phenotype TDBGH, selected by virulence to resistance gene Lr24, was the most common phenotype in the United States, and was found throughout the Great Plains region. Virulence phenotype MCDSB with virulence to Lr17a and Lr26 was the second most common phenotype and was found widely in the wheat growing regions of the United States. Virulence phenotype MFPSC, which has virulence to Lr17a, Lr24, and Lr26, was the third most common phenotype, and was found in the Ohio Valley region, the Great Plains, and California. The highly diverse population of P. triticina in the United States will continue to present a challenge for the development of wheat cultivars with effective durable resistance to leaf rust.


2021 ◽  
Author(s):  
Henriette Goyeau

Abstract Leaf rust seldom kills wheat, but it is capable of causing 35-50% yield loss in endemic areas on susceptible cultivars, where severity levels of 25-40% are reached at the tillering stage and 100% at the flowering stage. The disease causes more damage worldwide than other wheat rusts. Quarantine is of no relevance as leaf rust is of worldwide occurrence and virulences spread freely between nations and zones. Crop losses are dependent on the genetic resistance of each cultivar, pathogen virulence and environmental conditions. Losses caused by leaf rust particularly originate from reductions of the wheat photosynthetic area. Infected plants normally produce a lower number of tillers, lower amounts of grains per head and smaller grains. The earlier the epidemic in the cropping season, the higher the yield losses. Mathematical models for estimating disease severity and crop losses have been developed based on multiple-point disease recording at different physiological stages of the plant (Burleigh et al., 1972; Eversmeyer and Kramer, 1998, 2000).


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.


Plant Disease ◽  
2005 ◽  
Vol 89 (12) ◽  
pp. 1360-1360 ◽  
Author(s):  
S. C. Bhardwaj ◽  
M. Prashar ◽  
S. Kumar ◽  
S. K. Jain ◽  
D. Datta

Lr19, a resistance gene originally transferred from Agropyron elongatum to wheat (Triticum aestivum L.), has remained effective worldwide against leaf rust (Puccinia triticina Eriks.) except in Mexico (1). This report records a new pathotype of P. triticina virulent on Lr19 from India. From 2003 to 2004, 622 wheat leaf rust samples from 14 states were subjected to pathotype analysis. Samples were established on susceptible wheat cv. Agra Local, and pathotypes were identified on three sets of differentials following binomial nomenclature (3). Virulence on Lr19 (Agatha T4 line) was observed in approximately 2% of samples. These samples were picked from Lr19 (NIL), cvs. Ajit, Lal Bahadur, Local Red, Lok1, and Nirbhay from Karnataka and Gujarat states. All Lr19 virulent isolates were identical. The reference culture is being maintained on susceptible wheat cv. Agra Local and has also been put under long-term storage in a national repository at Flowerdale. From 2004 to 2005, this pathotype was detected in 6.3% of samples from central and peninsular India. There is no wheat variety with Lr19 under cultivation in India, however, it is being used in wheat breeding programs targeted at building resistance against leaf and stem rusts. NIL's Lr19/Sr25 (LC25) and Lr19/Sr25 (82.2711) were also susceptible to this isolate, whereas Lr19/Sr25 (spring accession) was resistant. The new isolate, designated as 253R31 (77-8), appears to be close to the pathotype 109R31 (4) with additional virulence for Lr19. The avirulence/virulence formula of pathotype 253R31 is Lr9, 23, 24, 25, 26, 27+31, 28, 29, 32, 36, 39, 41, 42, 43, 45/Lr1, 2a, 2b, 2c, 3, 10, 11, 12, 13, 14a, 14b, 14ab, 15, 16, 17, 18, 20, 21, 22a, 22b, 30, 33, 34, 35, 37, 38, 40, 44, 48, and 49. To our knowledge, this is the first report of virulence on Lr19 from two states of India. On international rust differentials, it is designated as TGTTQ (2), and is different from CBJ/QQ (1), the other isolate reported virulent on Lr19 from Mexico. The Mexican isolate is avirulent on Lr1, 2a, 2b, 2c, 3ka, 16, 21, and 30 to which the Indian isolate is virulent. However, both isolates are avirulent on Lr9, 24, 26, 36, and Lr42. Among the wheat cultivars identified during the last 6 years, HD2824, HD2833, HD2864, HI1500, HS375, HUW 510, HW 2044, HW 5001, Lok 45, MACS 6145, MP4010, NW 2036, PBW 443, PBW 498, PBW 502, PBW 524, Raj 4037, UP 2565, VL 804, VL 829, and VL 832 and lines of wheat possessing Lr9, Lr23, Lr24, and Lr26 showed resistance to this pathotype. PBW 343, which occupies more than 5 million ha in India, is also resistant to this pathotype along with PBW 373. An integrated strategy using a combination of diverse resistance genes, deployment of cultivars by using pathotype distribution data, slow rusting, and adult plant resistance is in place to curtail selection of new pathotypes and prevent rust epiphytotics. References: (1) J. Huerta-Espino and R. P. Singh. Plant Dis. 78:640,1994. (2) D. V. Mc Vey et al. Plant Dis. 88:271, 2004. (3) S. Nagarajan et al. Curr. Sci. 52:413, 1983. (4) S. K. Nayar et al. Curr. Sci. 44:742, 1975.


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