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Introduction
Publications
Publications (185)
Among the thousands of rust species described, many are known for their devastating effects on their hosts which include major agriculture crops and trees. Hence, for over a century, these basidiomycete pathogenic fungi have been researched and experimented with. However, due to their biotrophic nature, they are challenging organisms to work with a...
Leaf rust, caused by Puccinia triticina Erikss., is globally the most widespread rust of wheat. Populations of P. triticina are highly diverse for virulence, with many different races found annually. The genetic diversity of P. triticina populations has been previously assessed using different types of DNA markers. Genotyping technologies that prov...
Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is a re-emerging disease exemplified by recent epidemics caused by new virulent races. Understanding the sources and origins of genetic variations in the pathogen populations globally can facilitate the development of better strategies in disease management. We analyzed 68 wheat stem rust...
Disease resistance (R) genes from wild relatives could be used to engineer broad-spectrum resistance in domesticated crops. We combined association genetics with R gene enrichment sequencing (AgRenSeq) to exploit pan-genome variation in wild diploid wheat and rapidly clone four stem rust resistance genes. AgRenSeq enables R gene cloning in any crop...
Important races of wheat stem rust in Ecuador
Wheat stem rust is a devastating disease that has incited severe epidemics resulting in extreme yield losses over the past century. Stem rust infection in plots of wheat line UC11075, known to carry the Sr38 resistance gene, was unusual and severe in February 2016 in a nursery at the Instituto Nacional de Investigaciones Agropecuarias Austro statio...
Puccinia graminis
f. sp.tritici(Pgt) causes wheat stem rust, a devastating fungal disease. TheSr35resistance gene confers immunity against this pathogen's most virulent races, including Ug99. We used comparative whole-genome sequencing of chemically mutagenized and naturalPgtisolates to identify a fungal gene namedAvrSr35that is required forSr35avi...
An unusual stem rust infestation occurred in German wheat fields in summer 2013. This study analysed 48 isolates derived from 17 Puccinia graminis f. sp. tritici (Pgt) samples and six races were identified: TKTTF, TKKTF, TKPTF, TKKTP, PKPTF and MMMTF. Infection type and genotypic data confirmed that none of these races belonged to the TTKS (Ug99) r...
Three members of the Puccinia genus, P. triticina (Pt), P. striiformis f.sp. tritici (Pst), and P. graminis f.sp. tritici (Pgt), cause the most common and often most significant foliar diseases of wheat. While similar in biology and life cycle, each species is uniquely adapted and specialized. The genomes of Pt and Pst were sequenced and compared t...
Three members of the Puccinia genus, P. triticina (Pt), P. striiformis f.sp. tritici (Pst), and P. graminis f.sp. tritici (Pgt), cause the most common and often most significant foliar diseases of wheat. While similar in biology and life cycle, each species is uniquely adapted and specialized. The genomes of Pt and Pst were sequenced and compared t...
Psychotria nervosa, commonly called "wild coffee" (Rubiaceae), is an important ethno-medicinal plant in India. In 2010, a new rust disease of P. nervosa was observed in three regions of Mysore District, Karnataka (India), with disease incidence ranging from 58 to 63%.Typical symptoms of the rust disease on wild coffee were prominently visible durin...
Frequent emergence of new variants in the Puccinia graminis f. sp. tritici (Pgt) Ug99 race group in Kenya has made pathogen survey a priority. We analyzed 140 isolates from 78 Pgt samples collected in Kenya between 2008 and 2014 and identified six races, including three not detected prior to 2013. Genotypic analysis of 20 isolates from 2013 and 201...
Psychotria nervosa, commonly called “wild coffee” (Rubiaceae) is an important ethno-medicinal plant in India. In 2010 a new rust disease of P. nervosa was observed in three regions of Mysore District, Karnataka (India) with disease incidence ranging from 58% to 63%.Typical symptoms of the rust disease on wild coffee were prominently visible during...
The recent resurgence of wheat stem rust caused by new virulent races of Puccinia graminis f. sp. tritici (Pgt) poses a threat to food security. These concerns have catalyzed an extensive global effort toward controlling this disease. Substantial research and breeding programs target the identification and introduction of new stem rust resistance (...
The Ug99 race (TTKSK) of wheat stem rust was first detected in Uganda in 1998 (Pretorius et al. 2000) and since then, seven additional variants have been reported: TTKSF, TTKST, TTTSK, TTKSP, PTKSK, PTKST, and TTKSF+ (Pretorius et al. 2012). In this study, 84 stem rust samples from the 2014 surveys of wheat fields in Africa (Kenya, 9; Uganda, 28; R...
The cereal rust fungi are destructive pathogens that affect grain production worldwide. Although the genomic and transcript sequences for three Puccinia species that attack wheat have been released, the functions of large repertories of genes from Puccinia still need to be addressed to understand the infection process of these obligate parasites. H...
MycoBank new deposit for taxon Puccinia mysuruensis S.
A severe stem rust epidemic occurred in southern Ethiopia during November 2013 to January 2014 with yield losses close to 100% on the most widely grown wheat cultivar, 'Digalu'. Sixty-four stem rust samples collected from the regions were analyzed. A meteorological model for airborne spore dispersal was used to identify which regions were most like...
Race Ug99 (TTKSK) of Puccinia graminis f. sp. tritici, detected in Uganda in 1998, has been recognized as a serious threat to food security because it possesses combined virulence to a large number of resistance genes found in current widely grown wheat (Triticum aestivum) varieties and germplasm, leading to its potential for rapid spread and evolu...
Stem (black) rust, caused by Puccinia graminis, has plagued cereal crop production (wheat, barley, rye and oat) since the early days of agriculture. P. graminis is an obligate biotroph with a complex life cycle that includes five spore stages and two hosts. The asexual stage (uredinal) has a broad host range that includes cereals and grasses. P. gr...
Growing population and income are projected to increase global demand for wheat by at least 60% by 2050. Additional wheat production should come from sustainable intensification of existing wheat-inclusive production systems rather than GHG-enhancing land clearing. The largest yield gaps for wheat are in developing countries where smallholder farms...
In 2005, weekly rain samples collected at 124 National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites in the eastern and central United States were screened for Asian soybean rust (ASR; Phakopsora pachyrhizi) urediniospores. Application of a quantitative polymerase chain reaction method detected P. pachyrhizi DNA in the fil...
The classification of brown leaf rust fungi (Puccinia recondite complex and allied species) on wheat (Triticum aestivum), rye (Secale cereale), and other grasses in the family Poaceae has experienced a long history of controversy and uncertainty due to the reduced morphological characteristics available for taxonomy and difficulty of conducting int...
The pathogenicity and identity was studied of a field sample (PcE) of crown rust fungus Puccinia coronata collected in Hungary on wild couch grass (Elymus repens) and of a field sample (Psb) of stripe rust (P. striiformis) collected in the Netherlands on California brome (Bromus carinatus). We focused on the analysis of the host susceptibility of c...
The disease development and population structure of Puccinia graminis f. sp. avenae, which causes stem rust on oats, were studied to investigate if sexual reproduction plays an important role in the epidemiology of the disease. The genetic population structure of P. graminis f. sp. avenae in Sweden was investigated by sampling 10 oat fields in July...
High-quality garlic is an emerging crop grown in Minnesota for local markets, community supported agriculture, and select restaurants. In July 2010, Allium sativum cv. German Extra Hardy Porcelain plants showing foliar symptoms typical of rust infection were brought to the Plant Disease Clinic at the University of Minnesota by a commercial grower f...
In September 2008, Veronica spicata ‘Royal Candles’ plants showing foliar symptoms typical of a rust infection were brought to the Plant Disease Clinic at the University of Minnesota. Plants were grown in a local nursery in Dakota County, Minnesota. A dark brown discoloration was apparent on the upper surface of the leaf with lighter brown pustules...
Background
Wheat leaf rust (Puccinia triticina Eriks; Pt) and stem rust fungi (P. graminis f.sp. tritici; Pgt) are significant economic pathogens having similar host ranges and life cycles, but different alternate hosts. The Pt genome, currently estimated at 135 Mb, is significantly larger than Pgt, at 88 Mb, but the reason for the expansion is unk...
Repeat elements found in three P. triticina BAC clones. BAC sequences were compared to RePBASE, a database containing characterized repeat elements from P. triticina (Pt), P. graminis tritici (Pgt), and P. striiformis tritici (Pst). Repeats are listed by position in the respective Pt BAC clone, DNA strand, and the species specific element. Table S2...
Several fungal pathogens have been identified on ornamental and native stands of switchgrass (Panicum virgatum L.). Diseases of switchgrass, particularly rust, have been largely neglected and are likely to become the major limiting factor to biomass yield and quality, especially when monocultured over a large acreage. Based on teliospore morphology...
Seven races have been described in the Ug99 race group of Puccinia graminis f. sp. tritici (2). Ug99-related races previously recorded in South Africa are TTKSF, TTKSP, and PTKST (4). In December 2010, severe stem rust infection of the winter wheat cv. Matlabas was observed for the first time in South Africa. Race analysis using the 20 North Americ...
Rust fungi are obligate biotrophic pathogens that cause considerable damage on crop plants. Puccinia graminis f. sp. tritici, the causal agent of wheat stem rust, and Melampsora larici-populina, the poplar leaf rust pathogen, have strong deleterious impacts on wheat and poplar wood production, respectively. Filamentous pathogens such as rust fungi...
Analysis of genome architecture used to define the threshold for long FIR genes. (A) Distribution of P. graminis f. sp. tritici and M. larici-populina genes according to the length of their FIRs. Genes were sorted into two-dimensional data bins for each genome and number of genes is shown by a colour code. Crosses indicate median value for the two...
Complete list of tribes with full annotation data and features matching. Microsoft Excel workbook containing (i) the list of proteins included in the tribe analysis with full annotation including effector properties, and (ii) the list of tribes with the number of proteins matching effector properties they contain.
(XLS)
Details of the complete hierarchical cluster tree presented in
Figure 4
.
(TXT)
List of known small-secreted cysteine rich proteins (SCRs) used to define SCR features, with associated references. Microsoft Excel worksheet.
(XLS)
Complete list of PFAM domains and Gene Ontology terms detected in the proteomes of rust fungi and secretome enrichment analysis. Microsoft Excel Workbook containing thirteen worksheets with the complete list of PFAM domain and Gene Ontology terms found in the secretome of rust fungi, enrichment values, P-value of chi-square test for enrichment with...
Typical secreted enzyme PFAM domains enriched in the secretome of rust fungi. Table providing enrichment fold, p-value of a chi-squared test for enrichment in secretome, number of total and secreted proteins and list of tribes containing the PFAM domains.
(DOC)
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Several fungal pathogens have been identified on ornamental and native stands of switchgrass (Panicum virgatum L.). Diseases of switchgrass, particularly rust, have been largely neglected and are likely to become the major limiting factor to biomass yield and quality, especially when monocultured over a large acreage. Based on teliospore morphology...
Isard, S. A., Barnes, C. W., Hambleton, S., Ariatti, A., Russo, J. M., Tenuta, A., Gay, D. A., and Szabo, L. J. 2011. Predicting soybean rust incursions into the North American continental interior using crop monitoring, spore trapping, and aerobiological modeling. Plant Dis. 95:1346-1357. Between 2005 and 2009, millions of U.S. and Canadian soybea...
The barley stem rust resistance gene Reaction to Puccinia graminis 1 (Rpg1), encoding a receptor-like kinase, confers durable resistance to the stem rust pathogen Puccinia graminis f. sp. tritici. The fungal urediniospores form adhesion structures with the leaf epidermal cells within 1 h of inoculation, followed by hyphae and haustorium formation....
Crouch, J. A., and Szabo, L. J. 2011. Real-time PCR detection and discrimination of the southern and common corn rust pathogens Puccinia poly-sora and Puccinia sorghi. Plant Dis. 95:624-632. Over the past several years, southern corn rust (SCR) outbreaks caused by the fungus Puccinia polysora have become increasingly problem-atic for corn growers i...
Rust fungi are some of the most devastating pathogens of crop plants. They are obligate biotrophs, which extract nutrients only from living plant tissues and cannot grow apart from their hosts. Their lifestyle has slowed the dissection of molecular mechanisms underlying host invasion and avoidance or suppression of plant innate immunity. We sequenc...
To obtain an understanding of the relationships of the basidiomycetes, especially those with horizontally partitioned metabasidia, and of the evolution of structural characters, members of nine orders and an additional four genera of simple-septate fungi (Auriculariales sensu lato) were studied using cladistic analysis of light microscopic and ultr...
Puccinia kuehnii and P. melanocephala cause orange and brown rust of sugarcane, respectively. Puccinia kuehnii has been confirmed in Asia, Australia and recently, the Caribbean basin, whereas P. melanocephala is distributed among the majority of sugarcane growing regions. Differentiating these two economically significant pathogens visually is prob...
The life history of Puccinia striiformis remains a mystery because the alternate host has never been identified. Inoculation of grasses using aeciospores from naturally infected Berberis chinensis and B. koreana resulted in infection on Poa pratensis, producing uredinia typical of stripe rust caused by P. striiformis. Analyses using real-time polym...
Transformation procedures have been developed for introducing cloned genes into all major cereals. These procedures are beginning to be used to enhance disease resistance, although progress is slowed by the 8 to 10 months required to obtain seed from the first generation of transformed plants. Genotype dependence, somaclonal variation, and lack of...
In summers of 2005 and 2006, rain was collected weekly at over 100 selected National Atmospheric Deposition Program/National Trends Network sites across the soybean-growing region of the central and eastern United States. Rain samples were screened for Phakopsora pachyrhizi (causal agent of soybean rust) DNA using a nested real-time polymerase chai...
In the area of Triticeae-pathogen interactions, highly parallel profiling of the transcriptome and proteome has provided entry
points to examine host reaction to various pathogens and pests. In particular, the molecular mechanisms underlying gene-for-gene
resistance and basal defense have been explored in the contrasting contexts of host vs. nonhos...
Puccinia graminis f. sp. tritici is the causal agent of stem rust disease in wheat. The rust fungus has caused devastating disease epidemics throughout history and is still posing a potential threat to wheat production in some regions of the world due to the appearance of new races. To develop microsatellite or simple sequence repeat (SSR) markers...
The stem rust resistance gene Sr36 confers a near-immune resistance reaction to many races of Puccinia graminis f. sp. tritici and is highly effective against race TTKSK (syn. Ug99), which possesses unusually broad virulence combinations. Because this gene is widely used in United States soft winter wheat germplasm and cultivars, it has been consid...
The stem rust resistance gene Sr24 is effective against most races of Puccinia graminis f. sp. tritici, including race TTKS (syn. Ug99), and is used widely in commercial wheat cultivars worldwide. In 2006, susceptible infection responses were observed on wheat lines and cultivars carrying Sr24 in a field stem rust screening nursery at Njoro, Kenya....
Spring black stem and leaf spot of alfalfa (Medicago sativa) caused by Phoma medicaginis var. medicaginis is an important disease of alfalfa in temperate regions of the United States, causing yield losses and decreasing forage quality. Isolates of the fungus vary in morphological and cultural characteristics, as well as aggressiveness on alfalfa. T...
Bacterial DNA contamination of rust fungal DNA can be a significant problem for sequencing the rust fungus. Sequence assembly is much more difficult if the sequence contigs are mixed with bacterial sequence. A quantitative real-time polymerase chain reaction (qPCR) assay was developed to quantify bacterial DNA within rust fungal DNA samples and the...
