scholarly journals Silencing of a Wheat Ortholog of Glucan Synthase-Like Gene Reduced Resistance to Blumeria graminis f. sp. tritici

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Cheng ◽  
Zihao Wang ◽  
Yanyan Ren ◽  
Pengfei Jin ◽  
Kangjie Ma ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Infection Type ◽  
Plant Immunity ◽  
Transcript Level ◽  
Blumeria Graminis ◽  
Virus Induced Gene Silencing ◽  
Crop Species ◽  
Glucan Synthase ◽  
Wheat Powdery Mildew ◽  
Wheat Leaves

Wheat powdery mildew, caused by the obligate biotrophic ascomycete fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is a major threat to wheat production worldwide. It is known that Arabidopsis thaliana glucan synthase-like 5 (AtGSL5) improves the resistance of wheat to powdery mildew by increasing its anti-penetration abilities. However, the function of glucan synthase-like (GSL) orthologs in crop species remains largely unknown. In this study, TaGSL22, a novel functional ortholog of AtGSL5, was isolated as the only Bgt-induced GSL gene in wheat. Phylogenetic analysis indicated that TaGSL22 was conserved within the group of Gramineae and showed a closer relationship to GSL orthologs from monocots than to those from dicots. The TaGSL22 transcript was highest in the wheat leaves, followed by stems then roots. TaGSL22 was localized in the cell membrane and cytoplasm of wheat protoplasts, as predicted by transmembrane structure analysis. In addition, expression of TaGSL22 was induced by the plant hormones ethylene (ETH) and salicylic acid (SA), but down-regulated by jasmonate (JA) and abscisic acid (ABA). The transcript level of TaGSL22 was up-regulated in the incompatible interaction between Bgt and wheat, whereas it remained relatively unchanged in the compatible interaction. Knocking down of TaGSL22 by virus-induced gene silencing (VIGS) induced a higher infection type in the wheat–Bgt interaction. The TaGSL22-silenced plants exhibited reduced resistance to Bgt, accompanied by decreased callose accumulation. Our study shows a conserved function of GSL genes in plant immunity associated with penetration resistance, and it indicates that TaGSL22 can be used to improve papilla composition and enhance resistance to wheat powdery mildew.

scholarly journals An important role for secreted esterase in disease establishment of the wheat powdery mildew fungus Blumeria graminis f. sp.tritici

2011 ◽  
Vol 57 (3) ◽  
pp. 211-216 ◽  
Author(s):  
Jie Feng ◽  
Feng Wang ◽  
Geoff R. Hughes ◽  
Susan Kaminskyj ◽  
Yangdou Wei
Keyword(s):  
Powdery Mildew ◽  
Blumeria Graminis ◽  
Powdery Mildew Fungus ◽  
Diisopropyl Fluorophosphate ◽  
Wheat Powdery Mildew ◽  
Leaf Surfaces ◽  
Indigo Blue ◽  
Serine Esterases ◽  
Wheat Leaves

The activity of esterase secreted by conidia of wheat powdery mildew fungus, Blumeria graminis f. sp. tritici, was assayed using indoxyl acetate hydrolysis, which generates indigo blue crystals. Mature, ungerminated, and germinating conidia secrete esterase(s) on artificial media and on plant leaf surfaces. The activity of these esterases was inhibited by diisopropyl fluorophosphate, which is selective for serine esterases. When conidia were inoculated on wheat leaves pretreated with diisopropyl fluorophosphate, both appressorial germ tube differentiation and symptom development were significantly impaired, indicating an important role of secreted serine esterases in wheat powdery mildew disease establishment.

scholarly journals The relative abundance of wheat Rubisco activase isoforms is post-transcriptionally regulated

2021 ◽  
Author(s):  
Juan Alejandro Perdomo ◽  
Peter Buchner ◽  
Elizabete Carmo-Silva
Keyword(s):  
Relative Abundance ◽  
Light Availability ◽  
Transcript Level ◽  
Rubisco Activase ◽  
Small Subunit ◽  
Diel Cycle ◽  
Diurnal Rhythms ◽  
Crop Species ◽  
Β Protein ◽  
Wheat Leaves

AbstractDiurnal rhythms and light availability affect transcription–translation feedback loops that regulate the synthesis of photosynthetic proteins. The CO2-fixing enzyme Rubisco is the most abundant protein in the leaves of major crop species and its activity depends on interaction with the molecular chaperone Rubisco activase (Rca). In Triticum aestivum L. (wheat), three Rca isoforms are present that differ in their regulatory properties. Here, we tested the hypothesis that the relative abundance of the redox-sensitive and redox-insensitive Rca isoforms could be differentially regulated throughout light–dark diel cycle in wheat. While TaRca1-β expression was consistently negligible throughout the day, transcript levels of both TaRca2-β and TaRca2-α were higher and increased at the start of the day, with peak levels occurring at the middle of the photoperiod. Abundance of TaRca-β protein was maximal 1.5 h after the peak in TaRca2-β expression, but the abundance of TaRca-α remained constant during the entire photoperiod. The redox-sensitive TaRca-α isoform was less abundant, representing 85% of the redox-insensitive TaRca-β at the transcript level and 12.5% at the protein level. Expression of Rubisco large and small subunit genes did not show a consistent pattern throughout the diel cycle, but the abundance of Rubisco decreased by up to 20% during the dark period in fully expanded wheat leaves. These results, combined with a lack of correlation between transcript and protein abundance for both Rca isoforms and Rubisco throughout the entire diel cycle, suggest that the abundance of these photosynthetic enzymes is post-transcriptionally regulated.

Changes in sterol composition with ontogeny of Blumeria graminis conidia

2000 ◽  
Vol 78 (10) ◽  
pp. 1288-1293 ◽  
Author(s):  
Jérôme Muchembled ◽  
Anissa Lounès-Hadj Sahraoui ◽  
Anne Grandmougin-Ferjani ◽  
Michel Sancholle
Keyword(s):  
Powdery Mildew ◽  
Plant Pathogen ◽  
Total Sterol ◽  
Sterol Composition ◽  
Blumeria Graminis ◽  
Erysiphe Graminis ◽  
Qualitative And Quantitative ◽  
Wheat Powdery Mildew

The total sterol composition of conidia of the obligate plant pathogen Blumeria (= Erysiphe) graminis f.sp. tritici has been analysed as a function of their ontogeny during sporulation. Two main classes of sterols were characterized: 24-ethylsterols (24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol) and 24-methylsterols (24-methylenecholesterol and episterol). Our results show that sterol composition is greatly modified during ontogeny of B. graminis conidia both at the qualitative and quantitative levels. In particular, 24-methylsterols, e.g., 24-methylenecholesterol and episterol, are the major sterols in old conidia whereas 24-ethylsterols, e.g., 24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol, are the main sterols in young conidia.Key words: Erysiphe, wheat powdery mildew, sterols, ontogeny.

scholarly journals Evaluation of resistance to powdery mildew and identification of resistance genes in wheat cultivars

2020 ◽  
Author(s):  
Xian Xin Wu ◽  
Yue Gao ◽  
Qiang Bian ◽  
Qian Sun ◽  
Xin Yu Ni ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Large Scale ◽  
Durable Resistance ◽  
Cost Effective ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Seedling Resistance ◽  
Initial Inoculum ◽  
Wheat Powdery Mildew

Abstract Background: Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici ( Bgt ), is a serious disease of wheat worldwide that can cause significant yield losses. Growing resistant cultivars is the most cost-effective and eco-soundly strategy to manage the disease. Therefore, a high breeding priority is to identify genes that can be readily used either singly or in combination for effective resistance to powdery mildew and alos in combination with genes for resistance to other diseases. Yunnan Province, with complex and diverse ecological environments and climates, is one of the main wheat growing regions in China. This region provides initial inoculum for starting epidemics of wheat powdery mildew in the region and other regions and thus, plays a key role in the regional and large-scale epidemics of the disease throughout China. The objectives of this study were to evaluate seedling resistance of 69 main wheat cultivars to powdery mildew and to determine the presence of resistance genes Pm3 , Pm8 , Pm13 , Pm16 , and Pm21 in these cultivars using gene specific DNA markers. Results: Evaluation of 69 wheat cultivars with six Bgt isolates showed that only four cultivars were resistant to all tested isolates, indicating that the overall level of powdery mildew resistance of Yunnan wheat cultivars is inadequate. The molecular marker results showed that 27 cultivars likely have at least one of these genes. Six cultivars were found likely to have Pm3 , 18 likely to have Pm8 , 5 likely to have Pm16 , and 3 likely to have Pm21 . No cultivar was found to carry Pm13 . Conclusion: The information on the presence of the Pm resistance genes in Yunnan wheat cultivars can be used in future wheat disease breeding programs. In particular, cultivars carrying Pm21 , which is effective against all Bgt races in China, should be pyramided with other effective genes to developing new cultivars with durable resistance to powdery mildew. Keywords: Blumeria graminis f. sp. tritici , Pm gene, molecular markers, wheat

scholarly journals TaMCA4, a Novel Wheat Metacaspase Gene Functions in Programmed Cell Death Induced by the Fungal Pathogen Puccinia striiformis f. sp. tritici

2012 ◽  
Vol 25 (6) ◽  
pp. 755-764 ◽  
Author(s):  
Xiaodong Wang ◽  
Xiaojie Wang ◽  
Hao Feng ◽  
Chunlei Tang ◽  
Pengfei Bai ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Fungal Pathogen ◽  
Puccinia Striiformis ◽  
Transcript Level ◽  
Structural Features ◽  
Virus Induced Gene Silencing ◽  
Wheat Leaves ◽  
Multicellular Organisms ◽  
Bax Gene

Programmed cell death (PCD) is a physiological process to remove redundant or harmful cells, for the development of multicellular organisms, or for restricting the spread of pathogens (hypersensitive response). Metacaspases are cysteine-dependent proteases which play an essential role in PCD. Triticum aestivum metacaspase 4 (TaMCA4) is a type II metacaspase gene cloned from ‘Suwon11’ wheat, with typical structural features such as peptidase C14 caspase domain and a long linker sequence between the two subunits. Transient expression of TaMCA4 in tobacco leaves failed to induce PCD directly but enhanced cell death triggered by a mouse Bax gene or a candidate effector gene from Puccinia striiformis f. sp. tritici. Enhancement of PCD was also observed in wheat leaves co-bombarded with TaMCA4. When challenged with the avirulent race of P. striiformis f. sp. tritici, the expression level of TaMCA4 in wheat leaves was sharply upregulated, whereas the transcript level was not significantly induced by the virulent race. Moreover, knocking down TaMCA4 expression by virus-induced gene silencing enhanced the susceptibility of Suwon11 to the avirulent race of P. striiformis f. sp. tritici and reduced the necrotic area at infection sites.

scholarly journals Virulence Structure of the Eastern U.S. Wheat Powdery Mildew Population

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1074-1082 ◽  
Author(s):  
Ryan Parks ◽  
Ignazio Carbone ◽  
J. Paul Murphy ◽  
David Marshall ◽  
Christina Cowger
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Geographic Distance ◽  
Restricted Gene Flow ◽  
Eastern United States ◽  
Phenotypic Differences ◽  
Wheat Powdery Mildew ◽  
Detached Leaves ◽  
Geographic Separation ◽  
Wheat Leaves

Little is known about the population structure of wheat powdery mildew in the eastern United States, and the most recent report on virulence in this population involved isolates collected in 1993–94. In the present study, wheat leaves naturally infected with powdery mildew were collected from 10 locations in the southeastern United States in 2003 and 2005 and a collection of 207 isolates was derived from single ascospores. Frequencies of virulence to 16 mildew resistance (Pm) genes were determined by inoculating the isolates individually on replicated plates of detached leaves of differential wheat lines. These virulence frequencies were used to infer local effectiveness of Pm genes, estimate virulence complexity, detect significant associations between pairs of pathogen avirulence loci, and assess whether phenotypic differences between pathogen subpopulations increased with geographic distance. In both years, virulence to Pm3a, Pm3c, Pm5a, and Pm7 was present in more than 90% of sampled isolates and virulence to Pm1a, Pm16, Pm17, and Pm25 was present in fewer than 10% of isolates. In each year, 71 to 88% of all sampled isolates possessed one of a few multilocus virulence phenotypes, although there were significant differences among locations in frequencies of virulence to individual Pm genes. Several significant associations were detected between alleles for avirulence to pairs of Pm genes. Genetic (phenotypic) distance between isolate subpopulations increased significantly (R2 = 0.40, P < 0.001) with increasing geographic separation; possible explanations include different commercial deployment of Pm genes and restricted gene flow in the pathogen population.

scholarly journals Application of Geographic Information Systems to Identify the Oversummering Regions of Blumeria graminis f. sp. tritici in China

Plant Disease ◽  
2013 ◽  
Vol 97 (9) ◽  
pp. 1168-1174 ◽  
Author(s):  
Boning Li ◽  
Xueren Cao ◽  
Lin Chen ◽  
Yilin Zhou ◽  
Xiayu Duan ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Spatial Interpolation ◽  
Operating Characteristic ◽  
Characteristic Curve ◽  
High Elevation ◽  
Blumeria Graminis ◽  
Weather Data ◽  
Average Temperature ◽  
Wheat Powdery Mildew ◽  
The Relationship

Blumeria graminis f. sp. tritici, the pathogen that causes wheat powdery mildew, can oversummer as mycelia or conidia on leaves of volunteer wheat plants in cool mountainous areas in China. In this study, the regions in China where B. graminis f. sp. tritici can oversummer were identified on the basis of the probability that temperature remains below a critical temperature that is lethal to B. graminis f. sp. tritici. Two methods, one describing the relationship between the average temperature (20 to 26°C) in a given continuous 10-day period and wheat powdery mildew severity, the other describing the relationship between the average temperature (26 to 33°C) and the number of lethal days on powdery mildew development, were used to calculate the oversummering probability using weather data for 743 sites across China. Spatial interpolation based on the ordinary kriging method was conducted for the regions without observation. Oversummering probability values were similar for most locations estimated between the two methods. The B. graminis f. sp. tritici oversummering regions in China were identified to be in mountainous or high-elevation areas, including most regions of Yunnan, west and central areas of Guizhou, south and northwest Sichuan, south and east Gansu, south Ningxia, north and west Shaanxi, central-north Shanxi, west Henan and Hubei, and some regions in Qinghai, Tibet, and Xinjiang. When the oversummering sites from this study were compared with observed survey data for some of these sites, about 90% of sites where B. graminis f. sp. tritici oversummering was observed had been found suitable by both methods. The coincidence frequency and the area under the receiver operating characteristic curve for model 2 were higher, albeit only slightly, than those for model 1. Thus, both methods may be used to assist in disease management and further investigation on pathogen oversummering.

scholarly journals Effect of Abscisic Acid on the Susceptibility of Wheat Leaves to Powdery Mildew Blumeria graminis f. sp. tritici

2020 ◽  
pp. 164-172
Author(s):  
Alexander V. Babosha
Keyword(s):  
Abscisic Acid ◽  
Powdery Mildew ◽  
Concentration Dependence ◽  
Blumeria Graminis ◽  
Negative Regulator ◽  
Complex Nature ◽  
Exogenous Aba ◽  
Wide Range ◽  
Immunomodulatory Properties ◽  
Wheat Leaves

Abscisic acid (ABA) plays an important role in the regulation of protective processes under stresses of various nature. In contrast to abiotic stresses, when a plant and a pathogen interact, this phytohormone is in most cases a negative regulator of resistance. However, even with a similar nature of pathogenesis, ABA can produce different effects. For example, ABA treatment in different experiments induced either a decrease or an increase in the susceptibility of cereals to powdery mildew. The aim of this work was to study the immunomodulatory properties of exogenous ABA depending on its concentration in the pathosystem composed of wheat Triticum aestivum L. plants and powdery mildew pathogen Blumeria graminis (DC.) Speer f. sp. tritici (syn. Erysiphe graminis). We studied the change in the number of pathogen colonies on susceptible wheat leaves (Zarya and Tavrichanka varieties) when two-week-old seedlings were treated with various ABA concentrations (0–9 μM) before and immediately after they were infected. When whole plants were used in the experiment, ABA was added to Knop’s solution; in experiments with detached leaves floating in Petri dishes, aqueous solutions of the phytohormone were used. Our results show that the magnitude and direction of the effect of exogenous ABA on the number of colonies of the pathogen depends on its concentration and the time of application relative to the moment of infection. ABA concentration dependence was variable in form: similar concentrations could be inhibitory, resulting in the minimum number of colonies, or stimulating, with the maximum number of colonies. At the same time, the pre-infection use of ABA was more likely to be inhibitory. The non-monotonicity and variation of the form of concentration dependence could probably account for the contradictory literature data on the immunomodulatory properties of ABA. The complex nature of the concentration dependence and the corresponding variation in the immunological state within a fairly wide range seem to ensure the Abscisic acid (ABA) plays an important role in the regulation of protective processes under stresses of various nature. In contrast to abiotic stresses, when a plant and a pathogen interact, this phytohormone is in most cases a negative regulator of resistance. However, even with a similar nature of pathogenesis, ABA can produce different effects. For example, ABA treatment in different experiments induced either a decrease or an increase in the susceptibility of cereals to powdery mildew. The aim of this work was to study the immunomodulatory properties of exogenous ABA depending on its concentration in the pathosystem composed of wheat Triticum aestivum L. plants and powdery mildew pathogen Blumeria graminis (DC.) Speer f. sp. tritici (syn. Erysiphe graminis). We studied the change in the number of pathogen colonies on susceptible wheat leaves (Zarya and Tavrichanka varieties) when two-week-old seedlings were treated with various ABA concentrations (0–9 μM) before and immediately after they were infected. When whole plants were used in the experiment, ABA was added to Knop’s solution; in experiments with detached leaves floating in Petri dishes, aqueous solutions of the phytohormone were used. Our results show that the magnitude and direction of the effect of exogenous ABA on the number of colonies of the pathogen depends on its concentration and the time of application relative to the moment of infection. ABA concentration dependence was variable in form: similar concentrations could be inhibitory, resulting in the minimum number of colonies, or stimulating, with the maximum number of colonies. At the same time, the pre-infection use of ABA was more likely to be inhibitory. The non-monotonicity and variation of the form of concentration dependence could probably account for the contradictory literature data on the immunomodulatory properties of ABA. The complex nature of the concentration dependence and the corresponding variation in the immunological state within a fairly wide range seem to ensure themaintenance of equilibrium in the pathosystem and the chances for survival of both the host plant and the pathogen.

scholarly journals Virulence structure and its genetic diversity analyses of Blumeria graminis f. sp. tritici isolates in China

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xian Xin Wu ◽  
Xiao Feng Xu ◽  
De Xin Ma ◽  
Rong Zhen Chen ◽  
Tian Ya Li ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Powdery Mildew ◽  
Expressed Sequence Tag ◽  
Virulence Gene ◽  
Blumeria Graminis ◽  
Northeastern China ◽  
Gansu Province ◽  
Clear Correlation ◽  
Wheat Powdery Mildew ◽  
Gene Data

Abstract Background Blumeria graminis f. sp. tritici (Bgt), the causal agent of wheat powdery mildew severely affects yield security wheat production in China. Understanding the virulence structure and genetic variations of this pathogen is important for breeding wheat lines resistant to wheat powdery mildew. However, information related to genes controlling resistance remains elusive. This study analyzes the virulence structure and the genetic diversity of pathogenic Bgt populations isolated from northeastern (Liaoning, Heilongjiang) and northwestern (Gansu) China, two representative wheat producing areas, on 37 wheat cultivars each carrying a known powdery mildew resistance (Pm) gene. Results Bgt isolates from northeastern China show higher frequencies of virulence genes than populations from Gansu Province. Many of the known Pm genes failed to provide resistance in this study. However, Pm21 provided 100% resistance to all isolates from all three provinces, obtained during two consecutive years, while Pm13 provided 100% resistance in Gansu. Pm13, Pm16, Pm18, and Pm22 also showed partial resistance in northeastern China, while Pm16, Pm18, Pm22, Pm5 + 6 and Pm2 + 6 +? maintained some resistance in Gansu. Genetic diversity among populations in different regions was detected by cluster analyses using expressed sequence tag-simple sequence repeat (EST-SSR). When the genetic similarity coefficient is relatively high, populations from the same regional origin are mostly clustered into one group while populations from different regions exhibit large genetic differences. Conclusion Pm21 remains the best choice for breeding programs to maintain resistance to Bgt. Only 58% of the isolates tested show a clear correlation between EST-SSR genetic polymorphisms and frequency of virulence gene data.

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