Loose Smut Of Wheat Research Articles

QPCR and loop mediated isothermal amplification for rapid detection of Ustilago tritici.

Loose smut of wheat caused by the basidiomycete fungus Ustilago tritici, a seed-borne disease, is difficult to control because of the expanse of wheat planting area and difficulty in pathogen detection. In this study, real-time fluorescence quantitative PCR (qPCR) and loop-mediated isothermal amplification (LAMP) assays are used to rapidly amplify the DNA of U. tritici. Five pairs of primers for qPCR and two series primers for LAMP were designed. Primarily, the specificity of the primer was assessed by using genomic DNA of U. tritici, Fusarium graminearum, Blumeria graminis, Rhizoctonia cerealis, Puccinia striiformis, Bipolaris sorokiniana, and Alternaria solani as templates. Further, the amplification systems were optimized. Finally, the sensitivity of qPCR and LAMP assays were evaluated. The results showed that the primer Y-430 F/R, Y-307 F/R, Y-755 F/R, and Y-139 F/R for qPCR and primers L-139 and L-988 for LAMP could be used for U. tritici detection. In the sensitivity test, the detection limit of qPCR assay was identified as 10 pg μL−1 of genomic DNA, the detection limit for LAMP assay was 100 fg μL−1. We successfully performed qPCR and LAMP assays on wheat loose smut wheat samples. This paper establishes two methods for U. tritici detection, which can be used for diagnosis of wheat loose smut in the laboratory and in the field.

Loose Smut of Wheat (Ustilago tritici) and Its Managements: A Review Article

Among all diseases of wheat, seed-borne diseases such as smuts and bunts are found in every area where the wheat is grown. It is one of quarantine diseases of wheat that reduces the quality of grain seeds. Loose smut of wheat is occurred in cool and moist climate conditions. The successful infection of loose smut can occur after the anthesis. The pathogen remains dormant in the mature seed and germinates with germinating seeds. The mycelium of the fungus grows in the crown node and finally invades the inflorescence tissues. It develops with the seed embryo. It is disseminated by infected seeds and air by short distance. The pathogen has different types of host range especially all species of triticum. It is also pathogenic on Aegilops and rye (secale cereal). Most of the inoculums sources of loose smut are infected wheat seeds and air borne teliospores from smutted heads. In every infected areas of wheat by loose smut, a new race may arise by recombination of pre-existing virulence genes or through mutations. So, different types of management systems such as using of certified seeds treated with protectant fungicides, planting of resistant cultivars is very important. Keywords: Wheat seeds, Loose smut, Ustilago tritici, seed-borne diseases DOI : 10.7176/JBAH/9-8-05 Publication date : April 30 th 2019

Физиологические эффекты действия на растения фунгицидов триазольной природы

The integrated protection of plants from diseases, pests and weeds is an essential element of technologies for their cultivation. Contemporary crop research involves the widespread use of fungicides, which is important not only for increasing plant productivity, but also in order to obtain a high-quality crop. Under conditions of significant spread, diseases such as wheat fusarium head blight, loose smut of wheat and rye, rye spur and others not only reduce the productivity of crops, but also prevent the use of grain crops for human nutrition or animal feed purposes. In addition to plant protection, measures aimed at managing crops are of great importance in cultivation technology. This is ensured by various technological methods, including the use of a variety of chemicals, including stimulants and regulators of plant growth and development. In addition to their main target effect, many pesticides are known to cause additional effects on plants. This is expressed not only in varying degrees of phytotoxic manifestations, but also in stimulating and growth-regulating effects. Knowledge of the direction of these effects will allow for more competent application of chemical plant protection products, as well as for obtaining positive and avoiding negative effects. Many contemporary large companies working in the field of plant protection inform agrarians about possible additional effects of the preparation. In addition to practical application, studying the influence of the physiological effects of preparations helps agriculturalists to understand the formation mechanisms of plant resistance to stress. The review discusses the physiological and biochemical effects of triazole fungicidal preparations on plants. Their retardant effect, ability to increase the content of photosynthetic pigments and sugars, effects on respiration, changes in the composition of fatty acids, increased resistance of plants to temperature stresses, water deficiency, as well as chloride salinity and oxidative stress are also clarified. The review also includes the results of our own research on the effects of tebuconazole and tebuconazole-containing protectants on the mechanisms of cold and frost resistance of cereals.

Characterization of Ustilago segetum tritici causing loose smut of wheat in northwestern India

Loose smut of wheat, caused by Ustilago segetum tritici, occurs in India wherever the crop is grown. Chemical seed treatments used by seed producers and farmers result in a low incidence of the disease. However, the deployment of loose smut resistant cultivars could lead to reduced use of seed treatment chemicals in the wheat crop. Knowledge of the virulence of natural populations of U. segetum tritici is necessary to identify effective host genes for resistance. Since the late 1980s, there have been sporadic reports on the virulence characteristics of the U. segetum tritici population in India, but the current status is unknown. Thirty-five isolates of U. segetum tritici were collected from cultivars grown at various locations in five states of northwestern India from 2008–2011. The collected isolates were characterized for virulence on the standard Canadian differential set developed by Nielsen. The isolates represented 6 races, representing 43% of the 35 isolates, with race T34 being the most common. Two new races, T59 and T60, were identified. Two individual isolates collected from Triticum aestivum representing 2 different races, T1 and T57, originated from geographically diverse regions. Race T1 is from Mansa (210 m above mean sea level) and T57 from Palampur (1220 m above mean sea level). The isolates corresponding to the other races were not restricted to a particular area or wheat type.

Mapping of the loose smut resistance gene Ut6 in wheat (Triticum aestivum L.)

Loose smut of wheat (Triticum aestivum L.) caused by Ustilago tritici (Pers.) Rostr. can cause considerable yield losses in the absence of appropriate management practices. The use of wheat varieties with loose smut resistance is an efficient and effective control technique. However, the development of commercial wheat lines with resistance to loose smut is time- and labour-consuming. DNA markers linked to loose smut resistance gene(s) would assist the development of loose smut resistant genotypes. The genetics of loose smut resistance was studied in an F5‐derived recombinant inbred line (RIL) population of 94 lines from the cross BW278/AC Foremost. The line AC Foremost is resistant and line BW278 is susceptible to U. tritici race T10. Phenotypic assessment revealed that a single gene, designated Ut6, segregated for resistance to race T10 in the RIL population. A modified bulked segregant analysis identified a microsatellite marker linked to Ut6. A linkage map was developed consisting of linked microsatellite loci and the resistance gene. The loose smut resistance gene Ut6 mapped to the long arm of chromosome 5B. Five microsatellite markers mapped within 6.7 cM of Ut6. The microsatellite markers gpw5029 and barc232 flanked Ut6 at distances of 1.3 and 2.8 cM on the distal and proximal sides, respectively. A diverse set of wheat lines was haplotyped for Ut6 using the linked microsatellite markers gpw5029 and barc232. The haplotype analysis suggested that the microsatellite markers associated with Ut6 will be useful for marker-assisted selection of loose smut resistant wheat lines.

Farmer’s seed sources and seed quality: 2. seed health

The study assessed the health quality of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) seed samples collected from formal and informal sector in Ethiopia and Syria. In Ethiopia, several seed-borne fungi were found on wheat samples: Cochliobolus sativum, Fusarium avenaceum, F. graminearum, F. nivale, F. poae and Septoria nodorum. C. sativum was predominant with 84% of samples infected (frequency) and 1.85% mean infection level (rate) followed by F. graminearum with 74% and 1.54%, respectively. Certified seed consistently showed less infection for most seed-borne pathogens. In Syria, 68% and 14%, respectively, of wheat samples were infected with common bunt (Tilletia spp) and loose smut (Ustilago tritici). Mean loose smut infection rate was 0.79%. In barley, 85% of samples were infected with covered smut (Ustilago hordei) and 83% with loose smut (Ustilago nuda). Mean loose smut infection rate was 18%. Wheat seed health was better than of barley in terms of frequency and rate of infection. In Ethiopia, significant difference (P<0.001) in infection levels was detected for most pathogens from different seed sources, but not in Syria. There were significant differences (P<0.001) in mean infection levels across regions and districts for both crops in Ethiopia and Syria. All seed samples infected with loose smut of wheat or barley were in excess of minimum standards for seed certification across West Asia and North Africa, showing fundamental weaknesses in seed health from both formal and informal sources. National seed programs should set realistic standards and introduce routine testing to produce healthy seed.

Eight loci for resistance toUstilago triticirace T11 indicated in 20 wheat lines

Loose smut of wheat is a disease of world wide significance. Resistant cultivars constitute a potentially useful and environmentally benign method of controlling this disease. The genetic basis of resistance in 20 wheat genotypes with resistance to Ustilago tritici race T11 was studied in crosses with the widely grown but susceptible Indian cultivar, PBW 343. These lines were also involved in 10 ‘resistant × resistant’ crosses, to infer diversity for resistance genes in this set. All 30 crosses were developed to the F3 stage. Fifteen parents were inferred to carry dominant genes for resistance to race T11. Ten of these resistant lines (ML 521, W 59, W 1616, W 2484, W 2531, W 5915, W 6202, WL 1786, WL 2956 and WL 3450) had resistance controlled by 2 dominant genes acting in a complementary manner whereas in 4 lines (W 4461, W 5100, W 2615 and WL 3951), there was a single dominant gene and in a single genotype, WL 5907, there were 2 dominant genes with duplicate gene action governing the resistance. In lines W 2139, W 3899, W 4985, W 5450 and W 5792 a single recessive gene conferred resistance. Inheritance in two crosses, one derived from a line possessing a single dominant gene and the other from a line possessing a single recessive gene was re-analyzed and successfully confirmed in F5 generation. The segregation of most of the ‘resistant × resistant’ crosses conformed to the inferences drawn about the parents in the ‘resistant × susceptible’ crosses.

Carboxin tolerant strains of Ustilago nuda and Ustilago tritici in Canada

Seed treatment with systemic fungicides is commonly used to control loose smut of barley, caused by Ustilago nuda, and loose smut of wheat, caused by Ustilago tritici. Historically, the most widely used active ingredient in these fungicides has been carboxin. Isolates of U. nuda that are resistant to carboxin have been reported in France and Italy. Three isolates of U. tritici collected in 1997 and two isolates of U. nuda collected in 1999 in Canada appeared to be insensitive to carboxin when assessed using a teliospore germination assay on carboxin-amended media. In planta, studies were conducted by inoculation of these isolates onto susceptible lines of wheat or barley with treatment or no treatment of the inoculated seed with carboxin at the recommended rate in Canada of 55 g ai carboxin / 100 kg seed or twice the rate (110 g ai carboxin/100 kg seed). When the inoculated seed was subsequently grown to heading, assessment of the percent of smutted spikes on the plants indicated that the three isolates of U. tritici and the two isolates of U. nuda were unaffected by the carboxin seed treatment at 55 g ai carboxin/100 kg seed. However, the incidence of loose smut on their respective hosts by three of these isolates was significantly reduced when the seed was treated at a rate of 110 g ai carboxin/100 kg seed. These results would suggest that these isolates of U. tritici and U. nuda are tolerant to carboxin rather than resistant, because, in general, higher doses of the fungicide in seed treatments reduced host disease incidence caused by these pathogenic isolates. Key words: fungicide resistance, loose smut, barley, wheat, Hordeum vulgare, Triticum aestivum, T. turgidum. Les fongicides systémiques sont couramment utilisés pour protéger les semences contre le charbon nu de l’orge causé par Ustilago nuda et celui du blé causé par Ustilago tritici. Traditionnellement, l’ingrédient actif le plus couramment utilisé dans ces fongicides a été la carboxine. Des isolats d’ U. nuda tolérants à la carboxine ont été signalés en France et en Italie. Trois isolats d’ U. tritici collectés en 1997 et deux d’ U. nuda collectés en 1999, au Canada, ont semblé être insensibles à la carboxine lorsqu’ils ont été évalués au cours d’un biotest de germination de téleutospores dans un milieu gélosé modifié contenant de la carboxine. Des études in planta ont été menées en inoculant avec ces isolats des lignées de blé ou d’orge qui leur étaient réceptives et dont les semences inoculées avaient été traitées ou pas avec de la carboxine à raison de 55 g matière active de carboxine/100 kg de semence, dose recommandée au Canada, ou à deux fois la dose (110 g matière active de carboxine/100 kg de semence). Par la suite, lorsque les semences inoculées atteignirent le stade de l’épi, l’évaluation du taux d’infection des épis par le charbon nu a montré que ni les trois isolats d’ U. tritici ni les deux d’ U. nuda étaient affectés par la carboxine lorsque les semences étaient traitées selon la dose recommandée. Toutefois, l’incidence du charbon nu causé par trois de ces isolats sur leurs hôtes respectifs était de beaucoup réduite lorsque la dose du traitement était doublée. Ces résultats suggéreraient que les isolats d’ U. tritici et d’ U. nuda tolèrent davantage la carboxine qu’ils y sont sensibles parce que, en général, les traitements qui contiennent des doses plus élevées de fongicide contribuent à diminuer l’incidence de la maladie causée par ces isolats pathogènes. Mots-clés : tolérance aux fongicides, charbon nu, orge, blé, Hordeum vulgare, Triticum aestivum, T. turgidum.

Hordeum jubatum and Ely muscanadensisplay no role in the epidemiology of loose smut of wheat in western Canada

Hordeum jubatum and Ely mus<i>canadensis</i>play no role in the epidemiology of loose smut of wheat in western Canada

Seven Races Identified in 15 Field Collections of Loose Smut of Wheat from the People's Republic of China

Seven Races Identified in 15 Field Collections of Loose Smut of Wheat from the People's Republic of China

Races of Loose Smut of Wheat in South Australia.

Races of Loose Smut of Wheat in South Australia.

Seed‐borne Pathogens on Wheat (Particularly Smuts) in Turkey1

The important seed‐borne diseases of wheat in Turkey are common bunt (Tilletia caries and T. foetida), loose smut (Ustilago nuda tritici), dwarf bunt (T. contraversa) and flag smut (Urocystis tritici). Seed treatment against common bunt is widely used in Turkey. The damage is about 10–15 %, sometimes 90 % in some fields where seeds are sown without treatment. About 10 % of wheat fields were infected with bunt during 1972–1974. Seed treatment with carboxin (Vitavax) is recommended against loose smut of wheat in Turkey, but has not yet been used. Some wheat varieties, especially Siirak (1593/51) wheat, are highly susceptible to loose smut. The proportion of smut‐infected heads reached 30–40 % in this variety and about 32 % of wheat fields were infected with loose smut during 1972–1974. The damage was about 6 % in infected fields. Yield losses were at least 35,000 tons. Dwarf bunt is distributed at high altitude (1300–2000 m) in eastern Turkey; 2500 ha of wheat fields are infected with dwarf bunt. The disease causes 1–80 % losses in some fields. The wheat variety Yayla 305 is recommended for infected areas. Flag smut is present in some areas of Turkey, but yield losses are not important. Seed treatment is effective against seed‐borne spores.

Two grasses as common hosts for all species of Ustilago parasitic on wheat, barley, and oats

The grass Agropyron tsukushiense var. transiens is native to Far East Asia, and Hordeum compressum is native to southern South America. They were found to be susceptible to all the races that they were tested to of the following: loose smut of wheat (Ustilago tritici): loose, covered, and false loose smut of barley (U. nuda, U. hordei, and U. nigra); loose and covered smut of oats (U. avenae and U. kolleri); and head smut of grasses (U. bullata). The two grasses are the first known common hosts for these smuts and will be used to study the relationships between these pathogens.

Host range of the smut species Ustilago nuda and Ustilago tritici in the tribe Triticeae

Thirty-seven species of the genera Aegilops, Agropyron, Elymus, Eremopyrum, Haynaldia, Hordeum, Secale, and Taeniatherum in the tribe Triticeae and six species of the genus Lolium in the tribe Festuceae were tested for their reaction to loose smut of barley, Ustilago nuda, and loose smut of wheat, U. tritici. One new host for U. nuda was found: Hordeum violaceum. Fifteen new hosts for U. tritici were found: Aegilops caudata, Ae. ovata, Ae. triuncialis, Agropyron caninum. A. fibrosum, A. scabrifolium, Elymus canadensis, E. dahuricus, E. virginicus. Haynaldia villosa, Hordeum brachyantherum, H. jubatum, H. marinum, Secale silvestre, and Taeniathernm crinitum. Six new hosts for both U. nuda and U. tritici were found and they are the first known common hosts for these fungi: Agropyron scabriglume. A. striatum, A. tsukushiense var. transiens, Hordeum bogdanii, H. brevisubulatum, and H. compressum. On all these hosts, the sori of U. nuda were covered by a thin membrane or peridium whereas the sori of U. tritici were naked. Spores formed on all hosts germinated in the manner typical for the species used for inoculation. The wild barley common in Canada. Hordeum jubatum, differentiated between races of loose smut of wheat, U. tritici. Six species of Lolium were resistant to U. nuda and U. tritici.

Inheritance of virulence of loose smut of wheat, Ustilago tritici, on the differential cultivars Renfrew, Florence × Aurore, Kota, and Little Club

Inheritance of virulence of Ustilago tritici on four cultivars of wheat was studied, using a cross between races T 1 and T 2. Two recessive genes for virulence were identified: Utv1 conditioned virulence on the cultivars Renfrew and Florence × Aurore; Utv2 conditioned virulence on Kota and Little Club.

REACTION OF TRITICALE AND SPRING RYE TO LOOSE SMUT OF WHEAT

Twenty-seven lines of triticale (Triticale hexaploide Lart.) were inoculated with a mixture of races T1 to T5 of loose smut of wheat (Ustilago tritici (Pers.) Rostr.); six lines were susceptible with the level of infection ranging up to 67%. The race virulent on three of the lines was found to be T4, a race characterized by virulence on cultivars of durum wheat (Triticum turgidum L.). Of 119 cultivars of spring rye (Secale cereale L.) that were inoculated with the mixture of races, 68 were infected. The races virulent on five cultivars were found to be T2 on four, and T4 on one. The level of infection ranged up to 37%.

Effect of carboxin on loose smut of wheat

Effect of carboxin on loose smut of wheat

Isolation and culture of monokaryotic haplonts of Ustilago tritici, observations on their physiology, and the taxonomic relationship between U. tritici and U. nuda

Spores of Ustilago tritici were germinated on a medium containing benzoic acid, which induces the formation of dikaryons and inhibits mitosis. After removal of benzoic acid from the medium, mitosis occurred and the four monokaryotic haplonts formed by one spore were isolated by microsurgery. Both mating types grow readily on a minimal medium, in contrast to U. nuda, whose mating type a is proline-deficient. This fundamental physiological difference, supported by previously known morphological differences, was used as evidence to retain U. tritici (loose smut of wheat) and U. nuda (loose smut of barley) as separate species.

Host-Parasite Relations in Loose Smut of Wheat

Host-Parasite Relations in Loose Smut of Wheat

Host-Parasite Relations in Loose Smut of Wheat

Host-Parasite Relations in Loose Smut of Wheat