scholarly journals Assessing the durability, stability, and usability of genetic resistance to a non‐native fungal pathogen in two pine species

2019 ◽  
Vol 2 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Richard A. Sniezko ◽  
Jeremy S. Johnson ◽  
Douglas P. Savin
Keyword(s):  
Fungal Pathogen ◽  
Genetic Resistance ◽  
Pine Species

scholarly journals Resistance to Anthracnose (Colletotrichum lentis, Race 0) in Lens spp. Germplasm

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1799
Author(s):  
Eleonora Barilli ◽  
Juan Moral ◽  
Thaïs Aznar-Fernández ◽  
Diego Rubiales
Keyword(s):  
Fungal Pathogen ◽  
Lens Culinaris ◽  
Severe Disease ◽  
Genetic Resistance ◽  
Germplasm Collection ◽  
Plant Mortality ◽  
Breeding Programs ◽  
Stem Damage ◽  
Moderate Resistance ◽  
Stem Lesions

Anthracnose, caused by the fungal pathogen Colletotrichum lentis, is a severe disease of lentil (Lens culinaris) causing premature defoliation, necrotic stem lesions that lead to plant wilting and death in susceptible varieties. Two races of C. lentis (0 and 1) have been described so far. Race 0 is the most virulent one and limited genetic resistance is available to date. To address this scarcity of resistance, we screened a germplasm collection covering different Lens spp. originating from different countries for C. lentis race 0 resistance. Leaf and stem damage and plant mortality were assessed on seedlings inoculated under controlled conditions. A significant variability was observed among accession. Most of the collection studied was highly susceptible, but some levels of resistance were identified in about 15% of the accessions. The highest levels of resistance were identified in L. ervoides accessions PI572330, PI572334 and PI572338. Moderate resistance was also identified in 10 L. culinaris ssp. culinaris accessions but not in the remaining species studied. Selected accessions showed potential to integrate several breeding programs.

scholarly journals An optimized sporulation method for the wheat fungal pathogen Pyrenophora tritici-repentis

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Silke Jacques ◽  
Leon Lenzo ◽  
Kofi Stevens ◽  
Julie Lawrence ◽  
Kar-Chun Tan
Keyword(s):  
Fungal Pathogen ◽  
Fungal Pathogens ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Genetic Resistance ◽  
Barley Cultivars ◽  
Pyrenophora Tritici Repentis ◽  
Substantial Progress ◽  
Crop Disease ◽  
Advance Research

Abstract Background The necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) causes tan (syn. yellow) spot of wheat and accounts for significant yield losses worldwide. Understanding the molecular mechanisms of this economically important crop disease is crucial to counteract the yield and quality losses of wheat globally. Substantial progress has been made to comprehend the race structure of this phytopathogen based on its production of necrotrophic effectors and genomic resources of Ptr. However, one limitation for studying Ptr in a laboratory environment is the difficulty to isolate high spore numbers from vegetative growth with mycelial contamination common. These limitations reduce the experimental tractability of Ptr. Results Here, we optimized a multitude of parameters and report a sporulation method for Ptr that yields robust, high quality and pure spores. Our methodology encompasses simple and reproducible plugging and harvesting techniques, resulting in spore yields up to 1500 fold more than the current sporulation methods and was tested on multiple isolates and races of Ptr as well as an additional seven modern Australian Ptr isolates. Moreover, this method also increased purity and spore harvest numbers for two closely related fungal pathogens (Pyrenophora teres f. maculata and f. teres) that cause net blotch diseases in barley (Hordeum vulgare), highlighting the usability of this optimized sporulation protocol for the wider research community. Conclusions Large-scale spore infection and virulence assays are essential for the screening of wheat and barley cultivars and combined with the genetic mapping of these populations allows pinpointing and exploiting sources of host genetic resistance. We anticipate that improvements in spore numbers and purity will further advance research to increase our understanding of the pathogenicity mechanisms of these important fungal pathogens.

scholarly journals An Optimized Sporulation Method for the Wheat Fungal Pathogen Pyrenophora Tritici-Repentis

2021 ◽  
Author(s):  
Silke Jacques ◽  
Leon Lenzo ◽  
Kofi Stevens ◽  
Julie Lawrence ◽  
Kar-Chun Tan
Keyword(s):  
Fungal Pathogen ◽  
Fungal Pathogens ◽  
Molecular Mechanisms ◽  
Genetic Resistance ◽  
Barley Cultivars ◽  
Pyrenophora Tritici Repentis ◽  
Substantial Progress ◽  
Crop Disease ◽  
Advance Research ◽  
Host Genetic

Abstract BackgroundThe necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) causes tan (syn. yellow) spot of wheat and accounts for significant yield losses worldwide. Understanding the molecular mechanisms of this economically important crop disease is crucial to counteract the yield and quality losses of wheat globally. Substantial progress has been made to comprehend the race structure of this phytopathogen based on its production of necrotrophic effectors and genomic resources of Ptr. However, one limitation for studying Ptr in a laboratory environment is the difficulty to isolate high spore numbers from vegetative growth with mycelial contamination common. These limitations reduce the experimental tractability of Ptr. ResultsHere, we optimized a multitude of parameters and report a sporulation method for Ptr that yields robust, high quality and pure spores. Our methodology encompasses simple and reproducible plugging and harvesting techniques, resulting in spore yields up to 1,500 fold more than the current sporulation methods and was tested on multiple isolates and races of Ptr as well as an additional seven modern Australian Ptr isolates. Moreover, this method also increased purity and spore harvest numbers for two closely related fungal pathogens (Pyrenophora teres f. maculata and f. teres) that cause net blotch diseases in barley (Hordeum vulgare), highlighting the usability of this optimized sporulation protocol for the wider research community. ConclusionsLarge-scale spore infection and virulence assays are essential for the screening of wheat and barley cultivars and combined with the genetic mapping of these populations allows pinpointing and exploiting sources of host genetic resistance. We anticipate that improvements in spore numbers and purity will further advance research to increase our understanding of the pathogenicity mechanisms of these important fungal pathogens.

scholarly journals Genome Sequence Resource for Pathogen Bipolaris sorokiniana Shoemaker GN1 Causing Spot Blotch of Barley (Hordeum vulgare L.)

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1574-1577
Author(s):  
Yaxiong Meng ◽  
Juncheng Wang ◽  
Bin Bai ◽  
Le Wang ◽  
Lirong Yao ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Genome Sequence ◽  
Fungal Pathogen ◽  
Genetic Resistance ◽  
Bipolaris Sorokiniana ◽  
Spot Blotch ◽  
Hordeum Vulgare L ◽  
Illumina Hiseq ◽  
Highly Virulent ◽  
Specific Virulence

Spot blotch, caused by fungal pathogen Bipolaris sorokiniana Shoemaker, is one of the most frequent diseases affecting barley-growing regions worldwide. In this study, we reported the genome sequence of the highly virulent B. sorokiniana strain GN1 using the Illumina HiSeq 4000 platform. In total, 57 million 150-nucleotide paired-end clean reads were obtained and assembled into 96 scaffolds with an estimated genome size of 34.33 Mb. Furthermore, we identified genes that may be associated with strain-specific virulence and performed phylogenetic analysis of GN1 with five other Bipolaris spp. These results for GN1 will provide important information in understanding its molecular underpinning of pathogenicity and help identify novel sources of genetic resistance for improving disease resistance in barley.

scholarly journals Evaluation of Adapted Wheat Cultivars for Tolerance to Pythium Root Rot

Plant Disease ◽  
2004 ◽  
Vol 88 (9) ◽  
pp. 1027-1032 ◽  
Author(s):  
R. W. Higginbotham ◽  
T. C. Paulitz ◽  
K. G. Campbell ◽  
K. K. Kidwell
Keyword(s):  
Root Rot ◽  
Fungal Pathogen ◽  
Genetic Resistance ◽  
The United States ◽  
Wheat Cultivars ◽  
Pythium Species ◽  
Wheat Genotypes ◽  
Pythium Root Rot ◽  
Ideal Method

Genetic resistance in wheat (Triticum aestivum) against Pythium species would be an efficient means of control of this major root fungal pathogen, but so far no source has been identified. In addition, no long-term, sustainable options for controlling Pythium root rot are available; therefore, identifying and then incorporating genetic resistance into wheat cultivars would create an ideal method of control for this disease. The objective of this study was to examine the level of tolerance to Pythium root rot among a diverse set of wheat germ plasm collected from all major wheat production regions in the United States. Pythium debaryanum isolate 90136 and P. ultimum isolate 90038, previously identified as the most virulent Pythium isolates on wheat, were used to infest pasteurized soil, which was seeded with wheat genotypes and placed in a growth chamber maintained at a constant 16°C with a 12-h photoperiod and ambient humidity. Length of the first leaf and plant height measurements were recorded, and roots were digitally scanned to create computer files that were analyzed using WinRhizo software for length and number of tips. Significant (P < 0.05) differences in plant variables were detected among wheat genotypes in the presence of both Pythium species, and a significant (P < 0.0001) correlation between plant stunting and root loss was detected. Based on both shoot and root measurements, Caledonia, Chinese Spring, MN97695, and OR942504 appear to be highly susceptible to Pythium root rot, whereas genotypes KS93U161, OH708, and Sunco were the most tolerant to this disease.

scholarly journals Quantitative Disease Resistance to White Pine Blister Rust at Southwestern White Pine’s (Pinus strobiformis) Northern Range

2021 ◽  
Vol 4 ◽  
Author(s):  
Jeremy S. Johnson ◽  
Richard A. Sniezko
Keyword(s):  
Disease Resistance ◽  
Major Gene ◽  
Genetic Resistance ◽  
Low Frequency ◽  
The United States ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Quantitative Disease Resistance ◽  
Blister Rust ◽  
Pine Species

White pine blister rust, caused by the non-native, invasive fungal pathogen Cronartium ribicola, is a significant cause of mortality in white pines (Pinus subgenus Strobus) in North America. Along with climate-driven range contraction, mortality from blister rust can seriously impact the abundance and distribution of the nine white pine species native to the United States and Canada. Very little evaluation of this disease in southwestern white pine (Pinus strobiformis) has been previously undertaken, but genetic resistance to the disease has been documented, including major gene resistance (MGR) conferred by a dominant R gene. Data is emerging suggesting that the species also has quantitative disease resistance (QR). Our results suggest QR occurs at low frequency, with perhaps 10% of trees having a moderate level (&gt; 35% survival). We assessed progeny arrays from 40 P. strobiformis families (1873 seedlings), originating from three populations, inoculated with C. ribicola. Subsequently, the seedlings were assessed for signs, symptoms and resulting impact in a common garden trial over a 7.5-year period to determine the types and frequency of resistance in a portion of this species’ range. There was a high incidence of both stem symptoms and mortality in the P. strobiformis families tested, and families ranged in survival from 0 to 84.6%. Three families had &gt; 70% survival, representing perhaps the highest documented QR to date in a North American white pine species. Approximately 29.1% of the 441 surviving seedlings showed no stem symptoms, and of the approximately 70.8% of seedlings surviving with infections only few (24 of 316) had infections of moderate to high severity. QR traits associated with improved survival were primarily related to lower severity of infection, a reduced number of stem symptoms, and an increased number of bark reactions. Despite the high overall susceptibility, the presence of QR appears to be at a frequency and level useful to forest managers involved in restoration and reforestation efforts.

scholarly journals Transcriptional Changes in Mycorrhizal and Nonmycorrhizal Soybean Plants upon Infection with the Fungal Pathogen Macrophomina phaseolina

2018 ◽  
Vol 31 (8) ◽  
pp. 842-855 ◽  
Author(s):  
Nathalie Marquez ◽  
María L. Giachero ◽  
Adrien Gallou ◽  
Humberto J. Debat ◽  
Sylvie Cranenbrouck ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Fungal Pathogen ◽  
Negative Impact ◽  
Genetic Resistance ◽  
Agricultural Practices ◽  
Integrated Approach ◽  
Macrophomina Phaseolina ◽  
Defense Responses ◽  
Transcriptional Changes

Macrophomina phaseolina is a soil-borne fungal pathogen with a wide host range that causes charcoal rot in soybean [Glycine max (L.) Merr.]. Control of the disease is a challenge, due to the absence of genetic resistance and effective chemical control. Alternative or complementary measures are needed, such as the use of biological control agents, in an integrated approach. Several studies have demonstrated the role of arbuscular mycorrhizal fungi (AMF) in enhancing plant resistance or tolerance to biotic stresses, decreasing the symptoms and pressure caused by various pests and diseases, including M. phaseolina in soybean. However, the specific contribution of AMF in the regulation of the plant response to M. phaseolina remains unclear. Therefore, the objective of the present study was to investigate, under strict in-vitro culture conditions, the global transcriptional changes in roots of premycorrhized soybean plantlets challenged by M. phaseolina (+AMF+Mp) as compared with nonmycorrhizal soybean plantlets (−AMF+Mp). MapMan software was used to distinguish transcriptional changes, with special emphasis on those related to plant defense responses. Soybean genes identified as strongly upregulated during infection by the pathogen included pathogenesis-related proteins, disease-resistance proteins, transcription factors, and secondary metabolism–related genes, as well as those encoding for signaling hormones. Remarkably, the +AMF+Mp treatment displayed a lower number of upregulated genes as compared with the −AMF+Mp treatment. AMF seemed to counteract or balance costs upon M. phaseolina infection, which could be associated to a negative impact on biomass and seed production. These detailed insights in soybean-AMF interaction help us to understand the complex underlying mechanisms involved in AMF-mediated biocontrol and support the importance of preserving and stimulating the existing plant-AMF associates, via adequate agricultural practices, to optimize their agro-ecological potential.

Studies on the Fungal Pathogen of Dutch Elm Disease

1981 ◽  
Vol 39 ◽  
pp. 400-401
Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo
Keyword(s):  
Fungal Pathogen ◽  
Fungal Growth ◽  
Polymyxin B ◽  
The United States ◽  
Dutch Elm Disease ◽  
Effective Control ◽  
Sabouraud Agar ◽  
Total Inhibition ◽  
Zones Of Inhibition ◽  
Control Plate

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.

Red Heart Disease in Pines Caused by Porodaedalea (Phellinus) pini in Florida

EDIS ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 3
Author(s):  
Yin-Tse Huang ◽  
Jeffrey Eickwort ◽  
Jiri Hulcr
Keyword(s):  
Heart Disease ◽  
Forest Resources ◽  
Fact Sheet ◽  
Cavity Nesting ◽  
Pine Species

All pine species in Florida are susceptible to red heart disease. The disease can decrease timber value and weaken trees, making them threats to people and property. In forests, however, the same disease can be beneficial to cavity-nesting animals like red-cockaded woodpeckers. This 3-page fact sheet written by Yin-Tse Huang, Jeffrey Eickwort, and Jiri Hulcr and published by the UF/IFAS School of Forest Resources and Conservation describes the disease and provides some tips to manage it in areas where it could cause problems for people.http://edis.ifas.ufl.edu/fr425

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