The effect of phytoglobin overexpression on the plant proteome during nonhost response of barley (Hordeum vulgare) to wheat powdery mildew (Blumeria graminis f. sp. tritici)

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.

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

10.21203/rs.3.rs-19487/v1 ◽

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

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

Plant Disease ◽

10.1094/pdis-10-12-0957-re ◽

2013 ◽

Vol 97 (9) ◽

pp. 1168-1174 ◽

Cited By ~ 11

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.

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Identification of novel genetic factors underlying the host-pathogen interaction between barley (Hordeum vulgare L.) and powdery mildew (Blumeria graminis f. sp. hordei)

PLoS ONE ◽

10.1371/journal.pone.0235565 ◽

2020 ◽

Vol 15 (7) ◽

pp. e0235565 ◽

Cited By ~ 1

Author(s):

Maria Pogoda ◽

Fang Liu ◽

Dimitar Douchkov ◽

Armin Djamei ◽

Jochen C. Reif ◽

...

Keyword(s):

Hordeum Vulgare ◽

Powdery Mildew ◽

Genetic Factors ◽

Blumeria Graminis ◽

Hordeum Vulgare L ◽

Host Pathogen Interaction ◽

Host Pathogen

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

BMC Evolutionary Biology ◽

10.1186/s12862-019-1511-3 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 3

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

Canadian Journal of Microbiology ◽

10.1139/w10-120 ◽

2011 ◽

Vol 57 (3) ◽

pp. 211-216 ◽

Cited By ~ 5

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.

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Identity of barley powdery mildew resistances Bw and Ru2

Czech Journal of Genetics and Plant Breeding ◽

10.17221/60/2012-cjgpb ◽

2012 ◽

Vol 48 (No. 4) ◽

pp. 185-188 ◽

Cited By ~ 4

Author(s):

A. Dreiseitl

Keyword(s):

Hordeum Vulgare ◽

Powdery Mildew ◽

Spring Barley ◽

Blumeria Graminis ◽

Winter Barley ◽

Barley Cultivar ◽

Hordeum Vulgare L ◽

Barley Line ◽

Barley Powdery Mildew ◽

The Difference

A large number of resistances to powdery mildew (Blumeria graminis f.sp. hordei) and their combinations are known in barley (Hordeum vulgare L.). A similarity of resistance spectra between cultivars carrying the resistance Bw, designated for the winter barley cultivar Borwina, and the near-isogenic spring barley line P15, which carries the resistance Ru2, derived from the landrace Rupee, was found. The objective of this study was to test the difference between resistances Bw and Ru2. Six cultivars were tested, four with Bw and two with Ru2. Testing with 40 isolates showed identical reaction spectra between both groups. Testing of the cultivar Kompolti 4 (Bw) and line P15 (Ru2) with 300 isolates confirmed this result. Thus, the resistances currently designated Bw and Ru2 can be regarded as identical, and are determined by the gene Ml(Ru2). Both Bw and Ru2 should be designated by the earlier code, Ru2.

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Sensitivity of the U.S. wheat powdery mildew population to QoI fungicides and determination of the complete Blumeria graminis f. sp. tritici cytochrome b gene

Phytopathology ◽

10.1094/phyto-04-21-0132-r ◽

2021 ◽

Author(s):

Christina Cowger ◽

Emily A. Meyers ◽

Rebecca A. Whetten

Keyword(s):

Powdery Mildew ◽

Cytochrome B ◽

Blumeria Graminis ◽

Cytb Gene ◽

Qoi Fungicides ◽

Resistance Factors ◽

Wheat Powdery Mildew ◽

Mitochondrial Cytochrome B ◽

First Time ◽

The U.S

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is managed primarily with cultivar resistance and foliar fungicides. Quinone outside inhibitors (QoIs), which target the mitochondrial cytochrome b (cytb) gene, are one of the two main fungicide classes used on wheat. While European populations of B. graminis f. sp. tritici are widely insensitive to QoIs, largely due to the cytb mutation G143A, the QoI sensitivity of the U.S. B. graminis f. sp. tritici population had never been evaluated despite years of QoI use on U.S. wheat. A total of 381 B. graminis f. sp. tritici isolates from 15 central and eastern U.S. states were screened for sensitivity to QoI fungicides pyraclostrobin and picoxystrobin. A modest range of sensitivities was observed, with maximum resistance factors of 11.2 for pyraclostrobin and 5.3 for picoxystrobin. The F129L, G137R, and G143A cytb mutations were not detected in the U.S. B. graminis f. sp. tritici population, nor were mutations identified in the PEWY loop, a key part of the Qo site. Thus, no genetic basis for the observed quantitative variation in QoI sensitivity of U.S. B. graminis f. sp. tritici was identified. Isolate sporulation was weakly negatively associated with reduced QoI sensitivity, suggesting a fitness cost. In the course of the study, the complete B. graminis f. sp. tritici cytb gene sequence was determined for the first time in the isolate 96224 v. 3.16 reference genome. Contrary to previous reports, the gene has an intron that appears to belong to intron group II, which is unusual in fungi. The study was the first QoI sensitivity screening of a large, geographically diverse set of U.S. B. graminis f. sp. tritici isolates, and while the population as a whole remains relatively sensitive, some quantitative loss of efficacy was observed.

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