scholarly journals Whole genome resequencing and comparative genome analysis of three Puccinia striiformis f. sp. tritici pathotypes prevalent in India

2021 ◽  
Author(s):  
Inderjit Singh Yadav ◽  
S. C. Bhardwaj ◽  
Jaspal Kaur ◽  
Deepak Singla ◽  
Satinder Kaur ◽  
...  

Stripe rust disease of wheat, caused by Puccinia striiformis f. sp. tritici, ( Pst ) is one of the most serious diseases of wheat worldwide. In India, virulent stripe rust races have been constantly evolving in the North-Western Plains Zone leading to the failure of some of the most widely grown resistant varieties in the region. With the goal of studying the recent evolution of virulent races in this region, we conducted whole-genome sequencing of three prevalent Indian Pst pathotypes Pst46S119, Pst78S84 and Pst110S119. We assembled 58.62, 58.33 and 55.78 Mb of Pst110S119, Pst46S119 and Pst78S84 genome, respectively. Pathotypes were found to be highly heterozygous. Comparative phylogenetic analysis indicated the recent evolution of pathotypes Pst110S119 and Pst78S84 from Pst46S119. Pathogenicity-related genes classes (CAZyme, proteases, effectors, and secretome proteins) were identified and found to be under positive selection. Higher rate of gene family expansion was also observed in the three pathotypes. A strong association between the effector genes and transposable elements may be the source of the rapid evolution of these strains. Phylogenetic analysis differentiated the Indian races in this study from other known US, European, African and Asian races. Diagnostic markers developed for the identification of different Pst pathotypes will help tracking of yellow rust at farmers’ field and strategizing resistance gene deployment.

2018 ◽  
Vol 31 (11) ◽  
pp. 1117-1120 ◽  
Author(s):  
Chongjing Xia ◽  
Meinan Wang ◽  
Chuntao Yin ◽  
Omar E. Cornejo ◽  
Scot H. Hulbert ◽  
...  

Puccinia striiformis f. sp. tritici causes devastating stripe (yellow) rust on wheat and P. striiformis f. sp. hordei causes stripe rust on barley. Several P. striiformis f. sp. tritici genomes are available, but no P. striiformis f. sp. hordei genome is available. More genomes of P. striiformis f. sp. tritici and P. striiformis f. sp. hordei are needed to understand the genome evolution and molecular mechanisms of their pathogenicity. We sequenced P. striiformis f. sp. tritici isolate 93-210 and P. striiformis f. sp. hordei isolate 93TX-2, using PacBio and Illumina technologies and RNA sequencing. Their genomic sequences were assembled to contigs with high continuity and showed significant structural differences. The circular mitochondria genomes of both were complete. These genomes provide high-quality resources for deciphering the genomic basis of rapid evolution and host adaptation, identifying genes for avirulence and other important traits, and studying host-pathogen interactions.


Plant Disease ◽  
2021 ◽  
Author(s):  
Mercy Wamalwa ◽  
Ruth Wanyera ◽  
Julian Rodriguez-Algaba ◽  
Lesley Boyd ◽  
James Owuoche ◽  
...  

Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a major threat to wheat (Triticum spp.) production worldwide. The objective of this study was to determine the virulence of Pst races prevalent in the main wheat growing regions of Kenya, which includes Mt. Kenya, Eastern Kenya, and the Rift Valley (Central, Southern, and Northern Rift). Fifty Pst isolates collected from 1970 to 1992 and from 2009 to 2014 were virulence phenotyped using stripe rust differential sets, and 45 isolates were genotyped with sequence characterized amplified region (SCAR) markers to differentiate among the isolates and identify aggressive strains PstS1 and PstS2. Virulence corresponding to stripe rust resistance genes Yr1, Yr2, Yr3, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27 and the seedling resistance in genotype Avocet S were detected. Ten races were detected in the Pst samples obtained from 1970 to 1992, and three additional races were detected from 2009 to 2014, with a single race being detected in both periods. The SCAR markers detected both Pst1 and Pst2 strains in the collection. Increasing Pst virulence was found in the Kenyan Pst population, and that diverse Pst race groups dominated different wheat growing regions. Moreover, recent Pst races in east Africa indicated possible migration of some race groups into Kenya from other regions. This study is important in understanding Pst evolution and virulence diversity and useful in breeding wheat cultivars with effective resistance to stripe rust. Keywords: pathogenicity, Puccinia f. sp. tritici stripe (yellow) rust, Triticum aestivum


Author(s):  
Valeria Moreno Heredia

Yellow rust is caused by the fungus Puccinia striiformis f.sp.tritici (Pst), which due to its great migratory capacity, adaptation to different environments, and high levels of mutation; is one of the most devastating wheat diseases worldwide. Due to this, several strategies have been implemented to control the disease, the best being genetic improvement. The key to develop resistant cultivars is understanding the interactions between wheat and Pst. Therefore, this work synthesizes the most important investigations carried out in the last 30 years regarding: cellular, histological, and molecular interactions between wheat and Pst. This will allow a deeper and more complete understanding of the interaction between resistance and virulence genes in the yellow rust disease. The results of this work revealed that the early stage of infection, in susceptible and resistant cultivars, is the same qualitatively, but not quantitatively. However, a clear difference at the histological and molecular level, in terms of the amount and type of genes expressed, begins 48 hours after infection. It was also found that the haustorium, in addition to absorbing nutrients from the host; can also manipulate its metabolism to benefit itself, and can make some nutrients on its own. Keywords: haustorio, Puccinia striiformis f.sp.tritici, histological, resistance genes, virulence genes. Resumen La roya amarilla es causada por el hongo Puccinia striiformis f.sp.tritici (Pst), el cual debido a su gran capacidad migratoria, adaptación a diferentes ambientes, y niveles altos de mutación; es la enfermedad más devastadoras del trigo a nivel mundial. Debido a esto, varias estrategias han sido implementadas para controlar la enfermedad, siendo la mejor, el mejoramiento genético. La clave para desarrollar cultivares resistentes, es el entendimiento de las interacciones entre el trigo y Pst. Por lo tanto, este trabajo sintetiza las investigaciones más importantes realizadas en los últimos 30 años, en cuanto a interacciones celulares, histológicas y moleculares entre el trigo y Pst. Esto permitirá un entendimiento más profundo y completo de la interacción entre los genes de resistencia y virulencia, en la enfermedad de la roya. Los resultados revelaron que la fase temprana de infección en cultivares susceptibles y resistentes, es igual cualitativamente, pero no cuantitativamente. Sin embargo, una diferencia clara a nivel histológico y molecular, en cuanto a la cantidad y al tipo de genes expresados, empieza 48 hr post infección. También, se halló que el haustorio además de absorber nutrientes del huésped, también manipula el metabolismo de éste para su beneficio y puede elaborar algunos nutrientes por sí mismo. Palabras Clave: haustorio, Puccinia striiformis f.sp.tritici, histológico, genes de resistencia, genes de virulencia.


Author(s):  
Katravath Srinivas ◽  
Shaik Moizur Rahman ◽  
Manu Yadav ◽  
Mamta Sharma

Wheat is one of the most important staple food crops having global economic significance. Grown globally around 215 million hectares area with production of more than 600 million tons. Wheat is constrained in its production due to several biotic factors, among them yellow rust of wheat, Puccinia striiformis Westend. f.sp. tritici Eriks and Henn. (Pst) and brown rust of wheat, Puccinia recondita f.sp. tritici (Eriks. and E. Henn.) D.M. Henderson (Ptr) continues to be a serious threat and dominant factor limiting its yield potential globally. The estimated yield losses range from 10-70%, while in a severe epidemic the grain damage can be as great as 100%. Pathogens are considered to be favoured by the cooler areas but current races are more adaptable to high temperatures causing significant yield reduction in wheat. In India, prevalent pathotypes for yellow rust include 46S119, 110S119, and 238S119. Yr5, Yr10, Yr15, YrSp, and YrSk genes are resistant to Pst pathotypes in Indian conditions, while in the case of leaf rust of wheat, prevalent pathotypes are 77-5, 77-9, and 104-2. Lr9, Lr19, Lr24, Lr25, Lr29, Lr32, Lr39, Lr45, and Lr47 are the genes having resistance to Ptr pathotypes in Indian conditions. This publication provides a comprehensive overview of the stripe and leaf rusts of wheat in India and their virulent races, types of host resistance and provides a tool for effective management of wheat rust disease.


2021 ◽  
Author(s):  
Miaomiao Huang ◽  
Taiguo Liu ◽  
Shiqin Cao ◽  
Jonathan Yuen ◽  
Jiasui Zhan ◽  
...  

Puccinia striiformis f. sp. tritici is the causal agent of wheat yellow rust with records of regular and severe epidemics in China. This study explored the population dynamics of the yellow rust pathogen in Gangu, northwestern China. In Gangu, the Weihe River runs from west to east and divides Gangu into three regions: North and South mountain, with the valley in between. To study the genetic structure of the pathogen in local populations, samples were collected over 3 years from the three regions at different altitudes both within and between the wheat cropping seasons. A total of 811 P. striiformis f. sp. tritici isolates were successfully genotyped using 16 simple sequence repeat markers. The results suggest that P. striiformis f. sp. tritici can survive year-round in Gangu. The P. striiformis f. sp. tritici populations migrated among the regions, and the migration pattern was not related to altitude. The oversummering populations in the North and South mountain regions were genetically different from each other; and the P. striiformis f. sp. tritici populations collected from the lower altitude in the valley had no relationship with any of the populations collected in the spring or fall, indicating that they too have a different origin. Signatures of random mating were found in the populations collected in both North and South mountain regions, but not in the valley populations.


2009 ◽  
Vol 99 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Eugene A. Milus ◽  
Kristian Kristensen ◽  
Mogens S. Hovmøller

Stripe rust (yellow rust) of wheat, caused by Puccinia striiformis f. sp. tritici, has become more severe in eastern United States, Australia, and elsewhere since 2000. Recent research has shown that this coincided with a global spread of two closely related strains that were similar based on virulence phenotype and amplified fragment length polymorphism. The objective of this research was to quantify differences in aggressiveness among isolates representative of the pre-2000 and post-2000 populations. Representative isolates were evaluated at low (10 to 18°C) and high (12 to 28°C) temperature regimes for latent period, lesion length, lesion width, lesion area, and spore production on adult plants of a susceptible wheat cultivar with no known genes for resistance to stripe rust. “New” isolates (since 2000) were significantly more aggressive than “old” isolates (before 2000) for all variables. At the low temperature regime, new isolates sporulated 2.1 days (16%) sooner, grew 0.3 mm per day (18%) faster, produced 999 (140%) more spores per inoculation site per day, and produced 6.5 (71%) more spores per mm2 of lesion per day compared with old isolates. At the high temperature regime, new isolates sporulated 3 days (26%) sooner, grew 0.2 mm per day (18%) and 2.2 mm2 per day (88%) faster, grew 1.2 mm (50%) wider, produced 774 (370%) more spores per inoculation site per day, and produced 6.2 (159%) more spores per mm2 of lesion per day than old isolates. New isolates showed significant adaptation to the warm temperature regime for all variables. Based on these results and previously published models for stripe rust epidemics, recent severe stripe rust epidemics were most likely enhanced by the pathogen's increased aggressiveness, especially at higher temperature. Furthermore, these results demonstrate that wheat rust fungi can adapt to warmer temperatures and cause severe disease in previously unfavorable environments.


Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1534-1542 ◽  
Author(s):  
Anmin Wan ◽  
Xianming Chen

Puccinia striiformis f. sp. tritici causes stripe rust (yellow rust) of wheat and is highly variable in virulence toward wheat with race-specific resistance. During 2010, wheat stripe rust was the most widespread in the recorded history of the United States, resulting in large-scale application of fungicides and substantial yield loss. A new differential set with 18 yellow rust (Yr) single-gene lines was established and used to differentiate races of P. striiformis f. sp. tritici, which were named as race PSTv in distinction from the PST races identified in the past. An octal system was used to describe the virulence and avirulence patterns of the PSTv races. From 348 viable P. striiformis f. sp. tritici isolates recovered from a total of 381 wheat and grass stripe rust samples collected in 24 states, 41 races, named PSTv-1 to PSTv-41, were identified using the new set of 18 Yr single-gene differentials, and their equivalent PST race names were determined on the previous set of 20 wheat cultivar differentials. The frequencies and distributions of the races and their virulences were determined. The five most predominant races were PSTv-37 (34.5%), PSTv-11 (17.5%), PSTv-14 (7.2%), PSTv-36 (5.2%), and PSTv-34 (4.9%). PSTv-37 was distributed throughout the country while PSTv-11 and PSTv-14 were almost restricted to states west of the Rocky Mountains. The races had virulence to 0 to 13 of the 18 Yr genes. Frequencies of virulences toward resistance genes Yr6, Yr7, Yr8, Yr9, Yr17, Yr27, Yr43, Yr44, YrTr1, and YrExp2 were high (67.0 to 93.7%); those to Yr1 (32.8%) and YrTye (31.3%) were moderate; and those to Yr10, Yr24, Yr32, and YrSP were low (3.4 to 5.7%). All of the isolates were avirulent to Yr5 and Yr15.


2016 ◽  
Vol 67 (10) ◽  
pp. 1064 ◽  
Author(s):  
Beyhan Akin ◽  
Xian Ming Chen ◽  
Alex Morgunov ◽  
Nusret Zencirci ◽  
Anmin Wan ◽  
...  

Stripe (yellow) rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss., is one of the most damaging diseases in wheat and is especially damaging for winter and facultative wheat. The objective of this study was to understand stripe rust resistance in 100 wheat and facultative wheat entries from the International Winter Wheat Improvement Program by conducting experiments in a greenhouse and in four field environments in Washington State, USA, and by genotyping molecular markers linked to Yr genes. Percentages of entries resistant to the rust races at the seedling stage were: PST-17, 44%; PST-37, 32%; PST-43, 45%; PST-45, 49%; PST-116, 18%; PST-100, 17%; and PST-127, 8%. Molecular markers were positive for genes Yr9, Yr17, and Yr18 and negative for Yr5, Yr10, and Yr15. Yr18 was present in 44 entries (44%). By using the highly virulent races PST-127 and PST-100 under controlled conditions, 16 entries were shown to have high-temperature adult-plant (HTAP) resistance and resistant–moderately resistant field reactions at all four field sites. Resistant entries, especially those with HTAP resistance, were also identified in the field experiments.


2018 ◽  
Vol 10 (3) ◽  
pp. 410-423 ◽  
Author(s):  
Siham KHANFRI ◽  
Mohammed BOULIF ◽  
Rachid LAHLALI

Wheat (Triticum sp. L.), as one of the first domesticated food crops, is the basic staple food for a large segment of population around the world. The crop though is susceptible to many fungal pathogens. Stripe rust is an important airborne disease caused by Puccinia striiformis (Pst) and is widespread wherever wheat is cultivated throughout the world, in temperate-cool and wet environments. The causal fungus of stripe rust or yellow rust is an obligate parasite that requires another living host to complete its life cycle. Pst includes five types of spores in the life cycle on two distinct hosts. Stripe rust is distinguished from other rusts by the dusty yellow lesions that grow systemically in the form of streaks between veins and on leaf sheaths. The importance and occurrence of stripe rust disease varies in cultivated wheat, depending on environmental conditions (moisture, temperature, and wind), inoculum levels and susceptible host varieties. Transcaucasia was previously thought to be the center of origin for the pathogen. However, new findings further underlined Himalayan and near-Himalayan regions as center of diversity and a more tenable center of origin for P. striiformis. Long-distance dispersal of stripe rust pathogen in the air and occasionally by human activities enables Pst to spread to new geographical areas. This disease affects quality and yield of wheat crop. Early seeding, foliar fungicide application and cultivation of resistant varieties are the main strategies for its control. The emergence of new races of Pst with high epidemic potential which can adapt to warmer temperatures has expanded virulence profiles. Subsequently, races are more aggressive than those previously characterized. These findings emphasize the need for more breeding efforts of resistant varieties and reinforcement of other management practices to prevent and overcome stripe rust epidemic around the world.


2020 ◽  
Vol 110 (4) ◽  
pp. 933-942 ◽  
Author(s):  
Dipak Sharma-Poudyal ◽  
Qing Bai ◽  
Anmin Wan ◽  
Meinan Wang ◽  
Deven See ◽  
...  

Puccinia striiformis f. sp. tritici causes stripe rust (yellow rust), one of the most important wheat diseases worldwide. To understand the genetic variation of the pathogen in a global scale, 283 P. striiformis f. sp. tritici isolates collected from 16 countries in eight geographic regions were genotyped using 24 codominant simple sequence repeat markers. The overall collection had a high level of genetic diversity, and the diversity levels in the Asian populations were generally higher than those of the other regions. Heterozygosity of isolates ranged from 0 to 75%, with an average of 46%. Mean heterozygosity in individual countries ranged from 34 to 59%. A total of 265 multilocus genotypes (MLGs) were detected, which were classified into eight molecular groups. Some of the molecular groups were present in all geographic regions. Moreover, many isolates from different regions were found to be identical or very closely related MLGs. Analysis of molecular variance revealed high variation within countries and intermediate variation between countries, but it revealed low and insignificant variation among geographic regions. Pairwise comparisons of regional populations detected considerable effective migrants and only low to moderate levels of differentiation. The molecular genotypes had a moderate level of correlation with the virulence phenotypes, and some of the molecular/virulence groups contained isolates from different continents. The results indicate tremendous migrations of P. striiformis f. sp. tritici and warrant the development of management strategies considering the global pathogen population.


Sign in / Sign up

Export Citation Format

Share Document