scholarly journals Virulence diversity of Phakopsora pachyrhizi in Mexico

2021 ◽  
Author(s):  
Julio César García-Rodríguez ◽  
Zeferino Vicente-Hernández ◽  
Manuel Grajales-Solís ◽  
Naoki Yamanaka
Keyword(s):  
Comparative Analysis ◽  
South America ◽  
Geographic Variation ◽  
Soybean Rust ◽  
South American ◽  
Phakopsora Pachyrhizi ◽  
Common Trend ◽  
Asian Soybean Rust ◽  
Production Knowledge ◽  
Virulence Diversity

Asian soybean rust (ASR), caused by the pathogen Phakopsora pachyrhizi, is the main disease of soybean in Mexico and worldwide, threatening its production. Knowledge about the virulence of Mexican rust populations (MRPs) is crucial in order to develop or introduce soybean cultivars with resistance to this disease. This study investigated the geographic variation on the virulence of 19 MRPs collected in two states of Mexico: Tamaulipas and Chiapas, using a set of 12 differential soybean varieties. The inoculation of MRPs showed that there was no large difference in virulence to differentials carrying Rpp4 or Rpp5 between MRPs from the two states. However, a contrasting phenotype was observed on Rpp1, Rpp1-b, Rpp2, and Rpp3. In the comparative analysis of virulence profiles with 157 and 20 P. pachyrhizi samples from South America and Asia, respectively, the MRPs from Chiapas form an isolated cluster, including the Tamaulipas state. The MRPs from Tamaulipas clustered with South American samples because of common characteristics, such as virulence to Rpp1 and avirulence to Rpp1-b. However, opposite reactions on Rpp1 and Rpp1-b that have been reported in major USA pathogen were also observed in Chiapas samples. A common trend between Chiapas and major USA pathogen was also observed in Rpp3. As the main conclusion of the present study, the 1,000 km distance between these two states in Mexico makes a big difference in the virulence of ASR.

scholarly journals The origin and genetic diversity of the causal agent of Asian soybean rust,Phakopsora pachyrhizi, in South America

2014 ◽  
Vol 64 (3) ◽  
pp. 729-737 ◽  
Author(s):  
V. R. Jorge ◽  
M. R. Silva ◽  
E. A. Guillin ◽  
M. C. M. Freire ◽  
I. Schuster ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
South America ◽  
Causal Agent ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Asian Soybean Rust

scholarly journals Transcriptome analyses and virus induced gene silencing identify genes in the Rpp4-mediated Asian soybean rust resistance pathway

2013 ◽  
Vol 40 (10) ◽  
pp. 1029 ◽  
Author(s):  
Aguida M. A. P. Morales ◽  
Jamie A. O'Rourke ◽  
Martijn van de Mortel ◽  
Katherine T. Scheider ◽  
Timothy J. Bancroft ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Gene Silencing ◽  
Differentially Expressed ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
R Gene ◽  
Virus Induced Gene Silencing ◽  
Asian Soybean Rust ◽  
Defence Responses

Rpp4 (Resistance to Phakopsora pachyrhizi 4) confers resistance to Phakopsora pachyrhizi Sydow, the causal agent of Asian soybean rust (ASR). By combining expression profiling and virus induced gene silencing (VIGS), we are developing a genetic framework for Rpp4-mediated resistance. We measured gene expression in mock-inoculated and P. pachyrhizi-infected leaves of resistant soybean accession PI459025B (Rpp4) and the susceptible cultivar (Williams 82) across a 12-day time course. Unexpectedly, two biphasic responses were identified. In the incompatible reaction, genes induced at 12 h after infection (hai) were not differentially expressed at 24 hai, but were induced at 72 hai. In contrast, genes repressed at 12 hai were not differentially expressed from 24 to 144 hai, but were repressed 216 hai and later. To differentiate between basal and resistance-gene (R-gene) mediated defence responses, we compared gene expression in Rpp4-silenced and empty vector-treated PI459025B plants 14 days after infection (dai) with P. pachyrhizi. This identified genes, including transcription factors, whose differential expression is dependent upon Rpp4. To identify differentially expressed genes conserved across multiple P. pachyrhizi resistance pathways, Rpp4 expression datasets were compared with microarray data previously generated for Rpp2 and Rpp3-mediated defence responses. Fourteen transcription factors common to all resistant and susceptible responses were identified, as well as fourteen transcription factors unique to R-gene-mediated resistance responses. These genes are targets for future P. pachyrhizi resistance research.

scholarly journals Resistance to Asian soybean rust in soybean lines with the pyramided three Rpp genes

2013 ◽  
Vol 13 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Naoki Yamanaka ◽  
Noelle G Lemos ◽  
Miori Uno ◽  
Hajime Akamatsu ◽  
Yuichi Yamaoka ◽  
...  
Keyword(s):  
Genetic Background ◽  
Susceptible Variety ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Soybean Line ◽  
Pathogen Population ◽  
Resistance Level ◽  
Asian Soybean Rust ◽  
High Level

In this study, the influence of genetic background on the resistance level of a soybean line carrying Rpp2, Rpp4, and Rpp5 was evaluated by backcrossing it with a susceptible variety. It was also evaluated eight lines which carry these Rpp genes against five Asian soybean rust (ASR) isolates, in order to determine the likely range of resistance against ASR isolates differing in pathogenicity. The results indicated that a high level of resistance against various ASR isolates could be retained in lines carrying the three Rpp genes in susceptible genetic backgrounds, although minor influences of plant genetic background and ASR pathogenicity to the ASR resistance could occur. Thus, lines with the pyramided three Rpp genes should be effective against a complex pathogen population consisting of diverse Phakopsora pachyrhizi isolates.

scholarly journals Characterization of three soybean landraces resistant to Asian soybean rust disease

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Luciano Nobuhiro Aoyagi ◽  
Yukie Muraki ◽  
Naoki Yamanaka
Keyword(s):  
Susceptible Variety ◽  
Soybean Rust ◽  
Resistance Locus ◽  
Chromosome 6 ◽  
Phakopsora Pachyrhizi ◽  
Rust Disease ◽  
Asian Soybean Rust ◽  
The World ◽  
Trait Locus

Abstract Phakopsora pachyrhizi is an obligatory biotrophic fungus that causes Asian soybean rust (ASR) disease. ASR control primarily involves chemical control and the use of resistant soybean cultivars carrying an Rpp (resistance to P. pachyrhizi) gene. This study aimed to characterize the ASR resistance of three soybean Asian landraces. By screening the world core collection (WC) of soybean, which consists of 80 varieties, three landraces were identified in Southeast Asia as resistant to ASR. Genetic mapping using the F2 population derived from a cross with an ASR-susceptible variety, BRS 184, indicated that KS 1034 (WC2) has ASR resistance conferred by a single dominant resistance gene, mapped on chromosome 18, in the same region where Rpp1 was mapped previously. The BRS 184 × WC61 (COL/THAI/1986/THAI-80) F2 population, on the other hand, showed an ASR resistance locus mapped by quantitative trait locus analysis on chromosome 6, in the region where the resistance conferred by PI 416764 Rpp3 resides, with a logarithm of the odds score peak at the same position as the marker, Satt079, while the BRS 184 × WC51 (HM 39) population showed the resistance to ASR allocated between Satt079 and Sat_263 markers, also in the region where Rpp3 was mapped previously. Both WC51 and WC61 have the same infection profile as FT-2 and PI 462312 when tested against the same ASR isolate panel. These three WCs can be used in MAS programs for introgression of Rpp1 and Rpp3 and the development of ASR-resistant cultivars in the breeding program.

scholarly journals Models and applications for risk assessment and prediction of Asian soybean rust epidemics

2006 ◽  
Vol 31 (6) ◽  
pp. 533-544 ◽  
Author(s):  
Emerson M. Del Ponte ◽  
Cláudia V. Godoy ◽  
Marcelo G. Canteri ◽  
Erlei M. Reis ◽  
X.B. Yang
Keyword(s):  
Disease Modeling ◽  
Weather Conditions ◽  
Epidemiological Studies ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Spatial And Temporal Scales ◽  
Asian Soybean Rust ◽  
New Development ◽  
Glycine Max L ◽  
Favorable Weather

Asian rust of soybean [Glycine max (L.) Merril] is one of the most important fungal diseases of this crop worldwide. The recent introduction of Phakopsora pachyrhizi Syd. & P. Syd in the Americas represents a major threat to soybean production in the main growing regions, and significant losses have already been reported. P. pachyrhizi is extremely aggressive under favorable weather conditions, causing rapid plant defoliation. Epidemiological studies, under both controlled and natural environmental conditions, have been done for several decades with the aim of elucidating factors that affect the disease cycle as a basis for disease modeling. The recent spread of Asian soybean rust to major production regions in the world has promoted new development, testing and application of mathematical models to assess the risk and predict the disease. These efforts have included the integration of new data, epidemiological knowledge, statistical methods, and advances in computer simulation to develop models and systems with different spatial and temporal scales, objectives and audience. In this review, we present a comprehensive discussion on the models and systems that have been tested to predict and assess the risk of Asian soybean rust. Limitations, uncertainties and challenges for modelers are also discussed.

Asian soybean rust: a scientometric approach of Phakopsora pachyrhizi studies

Euphytica ◽  
2020 ◽  
Vol 216 (8) ◽  
Author(s):  
Daniela Meira ◽  
Leomar Guilherme Woyann ◽  
Antonio Henrique Bozi ◽  
Anderson Simionato Milioli ◽  
Eduardo Beche ◽  
...  
Keyword(s):  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Asian Soybean Rust

scholarly journals First Report of Phakopsora pachyrhizi, the Causal Agent of Asian Soybean Rust, on Florida Beggarweed in the United States

Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 972-972 ◽  
Author(s):  
L. E. Sconyers ◽  
R. C. Kemerait ◽  
J. H. Brock ◽  
R. D. Gitaitis ◽  
F. H. Sanders ◽  
...  
Keyword(s):  
United States ◽  
Pcr Primers ◽  
The United States ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Asian Soybean Rust ◽  
Abaxial Leaf Surface ◽  
Humidity Chamber ◽  
Average Size ◽  
Soybean Diseases

Phakopsora pachyrhizi Syd. & P. Syd., which causes Asian soybean rust (SBR), was observed on Florida beggarweed, Desmodium tortuosum (Sw) DC., in Attapulgus, GA during late October and early November 2005. Tan to brown lesions (<1.0 mm in diameter) consistent with symptoms of SBR (2) were observed on older leaves of several plants collected near an SBR-infected soybean trial. Dissection (40 to 60×) and compound microscopy (×200 to 400) revealed conical pustules and ellipsoid, echinulate urediniospores (average size 15 × 20 μm) on the abaxial leaf surface. Polymerase chain reaction (PCR) (primers Ppm1 and Ppa2) (1) was conducted on four samples to confirm identification of P. pachyrhizi or P. meibomiae. Three were positive for P. pachyrhizi, and one was negative for both species. Using morphology and real-time PCR, SBR was confirmed as P. pachyrhizi by the USDA/APHIS in Beltsville, MD. Six noninfected Florida beggarweed plants were transplanted to pots during December 2005 and grown at 22 to 24°C in a greenhouse. On 11 January 2006, a water suspension of urediniospores collected from SBR-infected soybeans (1 × 105 spores per ml) was spray inoculated on all leaves to almost runoff and incubated for 48 h in a plastic humidity chamber. Lesions, pustules, and urediniospores consistent with SBR (2) were observed on 3 February 2006. A PCR assay was conducted on six samples from the infected greenhouse plants and all were positive for P. pachyrhizi. Florida beggarweed is widespread in the southern United States and may serve as an additional overwintering source for P. pachyrhizi and a potential inoculum source for the soybean crop. References: (1) R. D. Fredrick et al. Phytopathology 92:217, 2002. (2) J. B. Sinclair and G. L. Hartman. Soybean rust. Pages 25–26 in: Compendium of Soybean Diseases. 4th ed. G. L. Hartman et al., eds. The American Phytopathological Society, St. Paul, MN, 1999.

scholarly journals An Overview of the Epidemiology of Phakopsora pachyrhizi in the State of Mato Grosso, Brazil

2021 ◽  
Vol 13 (6) ◽  
pp. 110
Author(s):  
Erlei Melo Reis ◽  
Wanderlei Dias Guerra ◽  
Mateus Zanatta ◽  
Laércio Zambolim
Keyword(s):  
Environmental Effect ◽  
The State ◽  
Soybean Rust ◽  
Economic Sustainability ◽  
Phakopsora Pachyrhizi ◽  
Airborne Spores ◽  
Mato Grosso ◽  
Asian Soybean Rust ◽  
Weed Plants ◽  
Soybean Plants

This review seeks to expand the knowledge about the epidemiology of Asian sybean rust in the state of Mato Grosso and contribute to ensuring the economic sustainability of soybean crop. It is discussed the Phakopsora pachyrhizi potential of dispersal from Asia to South America and finally to Mato Grosso state. The origin of the Asian soybean rust inoculum within Mato Grosso is addressed by the survival in volunteer and soybean weed plants (Pitelli, 2015) in other crops such as cotton. Data on the adverse environmental effect on the soybean plants survival are shown mainly the water deficit from June to August. Reports on the effect air temperature and mainly solar radiation on the mortality of airborne spores during their anemophilous spread on sunny days are also discussed. This increase of knowledge aims to make the soybean-free period more efficient by the knowledge on the soybean plants survival and on the fungus viability in the month of August. Due to the proximity of soybean farms, during the soybean-free period, in other states (Tocantins, Goi&aacute;s, Rond&ocirc;nia, etc.) and in other neighbor countries we discuss the likelihood that inoculum in the state may also originate in out-of-state crops during the Mato Grosso soybean-free period.

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