Resistance to bacterial speck disease in tomato occurs when the Pto kinase plant responds expression of avirulence gene avrPto Pseudomonas pathogen. Transient an transgene cells containing elicited a defense response. In yeast two-hybrid system, physically interacted with AvrPto. Alterations AvrPto or that disrupted interaction also abolished resistance plants. The physical and provides explanation gene-for-gene specificity resistance.

In 5 March 2001, a severe rust outbreak was recorded at Pitapó, Paraguay, and the causal organism determined to be Phakopsora pachyrhizi using polymerase chain reaction (PCR) DNA sequence analysis. May, surveys showed spread throughout most of Paraguay into western northern Parana, Brazil. 2001-02 season, widespread in but losses were reduced due drought; however, Brazil it more than 60% soybean acreage, causing field estimated 0.1 million metric tons (MMT). 2003, disease observed 90% fields...

Rapid-cycle real-time polymerase chain reaction (PCR) methods may revolutionize the manner in which plant pathogens are identified and diseases diagnosed. As genomics age progresses more DNA sequence data become available, highly specific primers fluorescent probe sequences can be designed to yield target amplicons unique regions of a pathogen's genome. Portable PCR instruments described here now allowing for diagnostic assays run directly field or at remote locations other than standard...

▪ Abstract Awareness of crop biosecurity and phytosanitation has been heightened since 9/11 the unresolved anthrax releases in October 2001. Crops are highly vulnerable to accidental or deliberate introductions pathogens from outside U.S. borders. Strategic thinking about protection against release a plant pathogen is an urgent priority. Rapid detection will be key success. This review summarizes recent progress development rapid real-time PCR protocols evaluates their effectiveness proposed...

Soybean rust occurs in all major soybean-growing regions of the world including North American mainland. rust, caused by Phakopsora pachyrhizi, is most destructive foliar disease soybean, and yield losses over 50% are common when environmental conditions conducive for development. Heavily infected plants defoliate mature more rapidly than not with rust. P. pachyrhizi has a broad host range can infect many other legumes some native to Australia. A number physiological races fungus have been...

ABSTRACT Few resistance loci to soybean rust (SBR), caused by Phakopsora pachyrhizi Syd., have been genetically mapped and linked molecular markers that can be used for marker assisted selection. New technologies are available single nucleotide polymorphism (SNP) genotyping rapidly map traits controlled such as SBR. Our objective was demonstrate the high‐throughput SNP method known GoldenGate assay perform bulked segregant analysis (BSA) find candidate regions facilitate efficient mapping of...

ABSTRACT Soybean rust (SBR), caused by Phakopsora pachyrhizi , was first discovered in North America 2004 and has the potential to become a major soybean [ Glycine max (L.) Merr.] disease USA. Currently, four SBR resistance genes have been identified but not mapped on genetic linkage map. One of these is Rpp1 gene, which present accession PI 200492 The availability molecular markers associated with will permit marker‐assisted selection expedite incorporation this gene into U.S. cultivars. We...

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi and recently discovered for the first time in continental United States, has been of concern to U.S. agricultural industry more than 30 years. Since little resistance is known, often difficult detect or quantitate, we initiated a project develop better, quantitative, method. The methodology determined average numbers diameters uredinia lesions that developed on leaves inoculated plants 14 days after inoculation. It was used compare...

The Pto kinase confers resistance in tomato to P. syringae pv. strains expressing the AvrPto protein. Physical interaction of and protein plant cell initiates host defense responses. recognition event between these two proteins is very specific; does not interact with other closely related kinases, including Fen kinase, which shares 80% amino acid identity Pto. By using Pto-Fen chimeric site-directed mutagenesis, we found that Thr-204 required for a yeast two-hybrid system specificity...

Soybean rust occurs in Australia and many countries throughout Africa, Asia, South America. The causal agents of soybean are two closely related fungi, Phakopsora pachyrhizi P. meibomiae, which differentiated based upon morphological characteristics the telia. Determination nucleotide sequence internal transcribed spacer (ITS) region revealed greater than 99% similarity among isolates either or but only 80% between species. Utilizing differences within ITS region, four sets polymerase chain...

The efficacy of fungicides in managing soybean rust was evaluated 12 environments South America and southern Africa over three growing seasons from 2002 to 2005. There were differences final severity, defoliation, yield among the treatments at most locations. In locations where not severe, all reduced severity. applications triazole + strobilurin resulted lower severity higher yields compared with other fungicides. provided highest many locations; however, tended be than that also between...

Soybean rust, caused by Phakopsora pachyrhizi (H. Sydow & Sydow), is a destructive soybean [ Glycine max (L.) Merr.] disease and identification of new resistance genes essential for effective rust management. Our research objectives were to map confirm the location gene(s) in PI 594538A using population 98 F 3:4 lines from cross between PI594538A (reddish‐brown [RB] lesions) susceptible cultivar Loda (tan [TAN] lesions). The inoculated with P. isolate ZM01‐1 Zimbabwe. RB mapped on...

Phakopsora pachyrhizi, the causal fungus of soybean rust, was discovered in continental U.S. November 2004. The presence this disease may have an impact on (Glycine max) production, as current commercial varieties are considered to be susceptible, and use one or more applications fungicides will add additional costs production. One objective USDA-ARS research rust is identify germplasm with resistance disease. There over 16,000 accessions USDA Germplasm Collection located at University...

A real-time fluorescent polymerase chain reaction (PCR) detection method for the sudden oak death pathogen Phytophthora ramorum was developed based on mitochondrial DNA sequence with an ABI Prism 7700 (TaqMan) Sequence Detection System. Primers and probes were also detecting P. pseudosyringae, a newly described species that causes symptoms similar to certain hosts. The species-specific primer-probe systems combined in multiplex assay plant system allow present extracted samples serve as...

Soybean rust, caused by the fungus Phakopsora pachyrhizi, was detected in continental United States 2004. Several new sources of resistance to P. pachyrhizi have been identified soybean (Glycine max); however, there is limited information about their when challenged with additional U.S. and international isolates. Resistance 20 (G. max) entries compared after inoculation 10 isolates, representing different geographic temporal origins. included 2 universal susceptible cultivars, 4 rust genes...

ABSTRACT Asian soybean rust (ASR) is an economically significant disease caused by the fungus Phakopsora pachyrhizi. The genes Rpp3 and Rpp?(Hyuuga) confer resistance to specific isolates of pathogen. Both map chromosome 6 (Gm06) (linkage group [LG] C2). We recently identified 12 additional accessions that harbor ASR mapping Gm06, within 5 centimorgans Rpp?(Hyuuga). To further characterize genotypes with on we used a set eight P. pachyrhizi collected from geographically diverse areas...

Rpp4 (Resistance to Phakopsora pachyrhizi 4) confers resistance 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 in mock-inoculated P. pachyrhizi-infected leaves resistant accession PI459025B (Rpp4) susceptible cultivar (Williams 82) across 12-day time course. Unexpectedly, two biphasic responses were identified. In incompatible...

The hrp/wts gene cluster of Pantoea stewartii subsp. is required for pathogenicity on sweet corn and the ability to elicit a hypersensitive response (HR) in tobacco. Site-directed transposon mutagenesis nucleotide sequencing were used identify genes within left 20 kb this cluster. Seventeen open reading frames (ORFs) comprise seven genetic complementation groups. These ORFs share homology with hrp dsp from Erwinia amylovora, chrysanthemi, Pseudomonas syringae pathovars have been designated,...

Five hundred thirty soybean accessions from maturity groups (MG) III through IX were evaluated for resistance to Phakopsora pachyrhizi in a replicated field trial at Centro Regional de Investigación Agrícola Capitán Miranda, Itapúa, Paraguay during the 2005-06 season. Soybean rust severities of individual ranged 0% (resistant) 30.0% (susceptible). In MG and IV, most resistant PI 506863, 567341, 567351B, with less than 1.2%. V, 181456, 398288, 404134B, 507305, 0.3%. VI, 587886, 587880A,...