scholarly journals Characterization of Kudzu (Pueraria spp.) Resistance to Phakopsora pachyrhizi, the Causal Agent of Soybean Rust

2010 ◽  
Vol 100 (9) ◽  
pp. 941-948 ◽  
Author(s):  
Stephen A. Jordan ◽  
Daniel J. Mailhot ◽  
Amanda J. Gevens ◽  
Jim J. Marois ◽  
David L. Wright ◽  
...  
Keyword(s):  
Early Onset ◽  
Soybean Rust ◽  
Natural Resistance ◽  
Phakopsora Pachyrhizi ◽  
Cytological Examination ◽  
North Central ◽  
Central Florida ◽  
The North ◽  
Polymerase Chain

Kudzu (Pueraria spp.) is an accessory host for soybean rust (SBR) (caused by Phakopsora pachyrhizi) that is widespread throughout the southeastern United States. An expanded survey of kudzu sites was conducted in 2008 to determine the proportion of natural resistance in the north-Florida kudzu population. Of the 139 sites evaluated, ≈18% were found to be free of SBR infection, while 23% had reduced sporulation. Ten accessions of kudzu from north-central Florida were characterized for their response to challenge by a single isolate of P. pachyrhizi under laboratory conditions. Three outcomes were observed: tan lesions with profuse sporulation (susceptible); reddish-brown lesions with delayed, reduced sporulation (resistant); and an immune response in which no lesions developed (immune). Of the 10 accessions, 6 were susceptible, 3 were immune, and 1 was resistant. Cytological examination revealed that resistant interactions were typified by early onset of a multicell hypersensitive response (HR) while typical immune interactions were the result of cell wall depositions that blocked penetration in combination with early onset of the HR. Quantitative real-time polymerase chain reaction was performed to determine the extent of colonization. After 15 days, there was 10-fold less P. pachyrhizi DNA present in resistant compared with susceptible kudzu, while the amount of P. pachyrhizi DNA present in the immune kudzu was below the detection level. Susceptible kudzu had approximately half the amount of P. pachyrhizi DNA present when compared with a susceptible soybean cultivar.

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 Characterization of a New Streptomyces Strain, DS3024, That Causes Potato Common Scab

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1329-1334 ◽  
Author(s):  
J. J. Hao ◽  
Q. X. Meng ◽  
J. F. Yin ◽  
W. W. Kirk
Keyword(s):  
Common Scab ◽  
Potato Tubers ◽  
North Central ◽  
Thaxtomin A ◽  
The North ◽  
Streptomyces Spp ◽  
Common Marker ◽  
Central United States ◽  
Potato Common Scab

A novel strain of Streptomyces (named DS3024) was isolated from a potato field in Michigan in 2006. The taxonomy of the organism was determined by morphology, biochemistry, and genetic analysis. Analysis of the 16S ribosomal RNA gene sequence indicated that the organism was most similar to an isolate of Streptomyces sp., ME02-6979.3a, which is not pathogenic to potato tubers but is distinct from other known pathogenic Streptomyces spp. Strain DS3024 has genes that encode thaxtomin synthetase (txtAB), which is required for pathogenicity and virulence, and tomatinase (tomA), which is a common marker for many pathogenic Streptomyces spp. However, the nec1 gene (associated with virulence in most pathogenic Streptomyces spp.) was not detected. The new strain was capable of growth at pH 4.5, caused necrosis on potato tuber slices, and produced thaxtomin A. In greenhouse experiments, DS3024 caused scab symptoms on potato tubers similar to those caused by Streptomyces scabies on tubers of potato cv. Atlantic, which is scab susceptible. We propose that DS3024 is a new strain of Streptomyces capable of causing common scab on potato tubers. The prevalence of this strain of Streptomyces in potato-producing areas in the north-central United States has not been determined.

scholarly journals Community Composition, Abundance, and Phenology of Stink Bugs (Hemiptera: Pentatomidae) in Soybean in the North Central Region of the United States

2019 ◽  
Vol 112 (4) ◽  
pp. 1722-1731 ◽  
Author(s):  
Daniela T Pezzini ◽  
Christina D DiFonzo ◽  
Deborah L Finke ◽  
Thomas E Hunt ◽  
Janet J Knodel ◽  
...  
Keyword(s):  
United States ◽  
Central Region ◽  
The United States ◽  
Growth Stages ◽  
Stink Bug ◽  
North Central Region ◽  
Stink Bugs ◽  
North Central ◽  
The North

Abstract Stink bugs (Hemiptera: Pentatomidae) are an increasing threat to soybean (Fabales: Fabaceae) production in the North Central Region of the United States, which accounts for 80% of the country’s total soybean production. Characterization of the stink bug community is essential for development of management programs for these pests. However, the composition of the stink bug community in the region is not well defined. This study aimed to address this gap with a 2-yr, 9-state survey. Specifically, we characterized the relative abundance, richness, and diversity of taxa in this community, and assessed phenological differences in abundance of herbivorous and predatory stink bugs. Overall, the stink bug community was dominated by Euschistus spp. (Hemiptera: Pentatomidae) and Chinavia hilaris (Say) (Hemiptera: Pentatomidae). Euschistus variolarius (Palisot de Beauvois) (Hemiptera: Pentatomidae), C. hilaris and Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) were more abundant in the northwestern, southeastern and eastern parts, respectively, of the North Central Region of the United States. Economically significant infestations of herbivorous species occurred in fields in southern parts of the region. Species richness differed across states, while diversity was the same across the region. Herbivorous and predatory species were more abundant during later soybean growth stages. Our results represent the first regional characterization of the stink bug community in soybean fields and will be fundamental for the development of state- and region-specific management programs for these pests in the North Central Region of the United States.

scholarly journals Epidemics of Soybean Rust (Phakopsora pachyrhizi) in Brazil and Paraguay from 2001 to 2003

Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 675-677 ◽  
Author(s):  
J. T. Yorinori ◽  
W. M. Paiva ◽  
R. D. Frederick ◽  
L. M. Costamilan ◽  
P. F. Bertagnolli ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Sequence Analysis ◽  
Soybean Rust ◽  
Severe Drought ◽  
Phakopsora Pachyrhizi ◽  
Chain Reaction ◽  
Causal Organism ◽  
Mato Grosso ◽  
Polymerase Chain ◽  
The Cost

In 5 March 2001, a severe rust outbreak was recorded at Pitapó, Paraguay, and the causal organism was determined to be Phakopsora pachyrhizi using polymerase chain reaction (PCR) and DNA sequence analysis. In May, rust surveys showed spread throughout most of Paraguay and into western and northern Parana, Brazil. In the 2001-02 season, rust was widespread in Paraguay, but losses were reduced due to severe drought; however, in Brazil it spread to more than 60% of the soybean acreage, causing field losses estimated at 0.1 million metric tons (MMT). In 2003, the disease was observed in more than 90% of the fields in Brazil, and the projected losses in Mato Grosso and Bahia alone are 2.2 MMT (US$487.3 million). Approximately 80% of the soybean acreage in Brazil was sprayed twice with fungicides at the cost of US$544 million. Differences in efficacy have been observed among the commercial strobilurin and triazol fungicides.

scholarly journals Polymerase Chain Reaction Assays for the Detection and Discrimination of the Soybean Rust Pathogens Phakopsora pachyrhizi and P. meibomiae

2002 ◽  
Vol 92 (2) ◽  
pp. 217-227 ◽  
Author(s):  
Reid D. Frederick ◽  
Christine L. Snyder ◽  
Gary L. Peterson ◽  
Morris R. Bonde
Keyword(s):  
Polymerase Chain Reaction ◽  
Nucleotide Sequence ◽  
Real Time ◽  
Sequence Similarity ◽  
Morphological Characteristics ◽  
Its Region ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Chain Reaction ◽  
Polymerase Chain

Soybean rust occurs in Australia and many countries throughout Africa, Asia, and South America. The causal agents of soybean rust are two closely related fungi, Phakopsora pachyrhizi and P. meibomiae, which are differentiated based upon morphological characteristics of the telia. Determination of the nucleotide sequence of the internal transcribed spacer (ITS) region revealed greater than 99% nucleotide sequence similarity among isolates of either P. pachyrhizi or P. meibomiae, but only 80% sequence similarity between the two species. Utilizing differences within the ITS region, four sets of polymerase chain reaction (PCR) primers were designed specifically for P. pachyrhizi and two sets for P. meibomiae. Classical and real-time fluorescent PCR assays were developed to identify and differentiate between P. pachyrhizi and P. meibomiae. Identification of P. pachyrhizi from infected soybean leaves using the real-time PCR assay will allow for more rapid diagnoses.

scholarly journals Molecular characterization of beta-tubulin from Phakopsora pachyrhizi, the causal agent of Asian soybean rust

2010 ◽  
Vol 33 (2) ◽  
pp. 354-358 ◽  
Author(s):  
Talles Eduardo Ferreira Maciel ◽  
Maíra Cristina Menezes Freire ◽  
Álvaro M.R. de Almeida ◽  
Luiz Orlando de Oliveira
Keyword(s):  
Molecular Characterization ◽  
Causal Agent ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Beta Tubulin ◽  
Asian Soybean Rust

Genetic characterization of loggerhead turtle (Caretta caretta) individuals stranded and caught as bycatch from the North-Central Adriatic Sea

2010 ◽  
Vol 31 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Fausto Tinti ◽  
Vincenzo Caputo ◽  
Silvia Franzellitti ◽  
Paola Nisi Cerioni ◽  
Carola Vallini ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Eastern Mediterranean ◽  
Genetic Relationships ◽  
Loggerhead Turtle ◽  
North Central ◽  
Mature Adults ◽  
The North ◽  
Control Region Sequences

AbstractThe North Adriatic Sea is considered a critical feeding and developmental area for Mediterranean loggerhead turtles. In this study, a comparative analysis of mitochondrial DNA control region sequences was carried out on sixty-five loggerhead individuals stranded and caught as bycatch in the Adriatic Sea from 1999 to 2002. We demonstrated the existence of genetic relationships between the North-Central Adriatic (NCA) aggregate and the Central-Eastern Mediterranean rookeries. Short-range and long-range migrations towards the Adriatic Sea were hypothesized by the finding of individuals bearing haplotypes endemic to the nesting populations of Greece and Turkey. The occurrence of individuals belonging to dimensional classes from juveniles to mature adults strongly support both the feeding and developmental role of the NCA.

A SEM Study of Epilithic and Endolithic Algae and Cyanophytes in Coquina Beach Rock of North Central Florida

2000 ◽  
Vol 6 (S2) ◽  
pp. 672-673
Author(s):  
N. C. Love ◽  
K. L. Kelley ◽  
J. S. Davis
Keyword(s):  
Beach Sand ◽  
Eastern Coast ◽  
North Central ◽  
Surf Clam ◽  
Central Florida ◽  
The North ◽  
Beach Rock ◽  
Fouling Organisms ◽  
A Site ◽  
Shell Fragments

The eastern coast of north central Florida is home to a habitat unique in the southeastern United States. Some areas of the north to north-central Florida beaches consist of outcroppings of coquina, a beach rock formed by shell fragments and sand held together by a calcareous cement. The major constituents of coquina are shell fragments of the surf clam Donax variabilis, while fragments of Area sp. and Dinocardium sp. are also generally present. These same shell fragments are also found loose comprising most of the beach “sand” in this area. The coquina serves as a substrate for a variety of attatched seaweeds and fouling organisms. Microalgae and cyanophytes of interest to this study can be classified as either epilithic or endolithic. Epilithic microorganisms inhabit the surface, using the rock primarily as a site of attatchment. The endolithic microorganisms are those algae and cyanophytes that actively bore into the coquina rock's shell fragments.

Characterization of Pythium spp. from Three Ohio Fields for Pathogenicity on Corn and Soybean and Metalaxyl Sensitivity

2004 ◽  
Vol 5 (1) ◽  
pp. 10 ◽  
Author(s):  
A. E. Dorrance ◽  
S. A. Berry ◽  
P. E. Lipps
Keyword(s):  
Seed Treatment ◽  
Soybean Seed ◽  
North Central Region ◽  
Grain Production ◽  
North Central ◽  
Stand Establishment ◽  
The North ◽  
The Us ◽  
Metalaxyl Sensitivity

Pythium spp. were baited with corn and soybean seed from soils collected from three locations in Ohio where soybean and corn stand establishment was a concern. Five species, P. catenulatum, P. irregulare, P. paroecandrum, P. splendens, and P. torulosum, were recovered and a subset of these isolates was then tested for pathogenicity on corn and soybean seed and sensitivity to the seed treatment fungicide metalaxyl. There was a range of both pathogenicity and sensitivity to metalaxyl within and among the Pythium spp. recovered from the three locations. A more thorough evaluation of the Pythium populations that exist in grain production fields in the north central region of the US is needed to facilitate the development and deployment of broader based seed treatment products. Accepted for publication 12 January 2004. Published 2 February 2004.

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