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Reduced tillage is considered as one of the main tools to save biological diversity; however, it increases pressure of diseases, including wheat leaf blotches. The aim of present study was to clarify the impact of reduced soil tillage on the development of winter wheat leaf blotches in different schemes of crop rotation. The impact of different growing technologies on the severity of winter wheat disease was evaluated in a two-factorial experiment: A - soil tillage system, and B - different combinations of wheat pre-pre-crop and pre-crop (wheat, oilseed rape, barley and faba beans). Diseases were assessed every 10 days approximately and total impact of diseases was evaluated by calculating AUDPC (Area under Diseases Progress Curve). Tan spot, caused by Pyrenophora tritici-repentis was dominated disease over the long period, regardless of meteorological conditions. Development of Septoria leaf blotch was not influenced by neither crop rotation nor soil tillage. The level of tan spot was essentially higher after wheat, regardless of the pre-pre-crop. Reduced soil tillage promoted severity of tan spot. Ploughing mitigated effect of previous crops and differences in tan spot level were insignificant. Despite many positive effects of conservation tillage, increasing of fungicide treatment could be necessary, in conditions, when the tan spot is most devastating and widespread wheat disease. [ABSTRACT FROM AUTHOR]

The ToxA effector is a major virulence gene of Pyrenophora tritici-repentis (Ptr), a necrotrophic fungus and the causal agent of tan spot disease of wheat. ToxA and co-located genes are believed to be the result of a recent horizontally transferred highly conserved 14kb region a major pathogenic event for Ptr. Since this event, monitoring isolates for pathogenic changes has become important to help understand the underlying mechanisms in play. Here we examined ToxA in 100 Ptr isolates from Australia, Europe, North and South America and the Middle East, and uncovered in isolates from Denmark, Germany and New Zealand a new variation, a novel 166 bp insertion element (PtrHp1) which can form a perfectly matched 59 bp inverted repeat hairpin structure located downstream of the ToxA coding sequence in the 3’ UTR exon. A wider examination revealed PtrHp1 elements to be distributed throughout the genome. Analysis of genomes from Australia and North America had 50–112 perfect copies that often overlap other genes. The hairpin element appears to be unique to Ptr and the lack of ancient origins in other species suggests that PtrHp1 emerged after Ptr speciation. Furthermore, the ToxA UTR insertion site is identical for different isolates, which suggests a single insertion event occurred after the ToxA horizontal transfer. In vitro and in planta-detached leaf assays found that the PtrHp1 element insertion had no effect on ToxA expression. However, variation in the expression of ToxA was detected between the Ptr isolates from different demographic locations, which appears to be unrelated to the presence of the element. We envision that this discovery may contribute towards future understanding of the possible role of hairpin elements in Ptr. [ABSTRACT FROM AUTHOR]

Monosporascus cannonballus and M. eutypoides are the causative agents of melons' root rot and vine decline, with little knowledge about their mechanisms of infection. M. cannonballus secretome was isolated and subdivided into two fractions based on molecular weight (smaller and larger than 10 kDa), and further separated via high voltage paper electrophoresis and SDS-PAGE, respectively. Large cell-free filtrates of the fungus were found to contain biologically active proteins that were further characterized via mass spectrometry and revealed to be α-1,2-mannosidase and serine protease. Meanwhile, biochemical analyses of low molecular weight compounds were suggestive to be similar to marasmines. Both fractions were capable of inducing phytotoxicity, once infiltrated into the melon leaves. This is the first report of phytotoxic compounds isolated from M. cannonballus contributing to disease induction in melon plants. [ABSTRACT FROM AUTHOR]

Background: Pyrenophora tritici-repentis (Ptr) is a necrotrophic fungal pathogen that causes the major wheat disease, tan spot. We set out to provide essential genomics-based resources in order to better understand the pathogenicity mechanisms of this important pathogen. Results: Here, we present eight new Ptr isolate genomes, assembled and annotated; representing races 1, 2 and 5, and a new race. We report a high quality Ptr reference genome, sequenced by PacBio technology with Illumina paired-end data support and optical mapping. An estimated 98% of the genome coverage was mapped to 10 chromosomal groups, using a two-enzyme hybrid approach. The final reference genome was 40.9 Mb and contained a total of 13,797 annotated genes, supported by transcriptomic and proteogenomics data sets. Conclusions: Whole genome comparative analysis revealed major chromosomal segmental rearrangements and fusions, highlighting intraspecific genome plasticity in this species. Furthermore, the Ptr race classification was not supported at the whole genome level, as phylogenetic analysis did not cluster the ToxA producing isolates. This expansion of available Ptr genomics resources will directly facilitate research aimed at controlling tan spot disease. [ABSTRACT FROM AUTHOR]

Tan spot caused by the necrotroph pathogen Pyrenophora tritici-repentis (Died.) Drechs. [anamorph Drechslera tritici-repentis ) (Died.) Shoem] causes reductions in yield and grain quality of wheat ( Triticum aestivum L.) by affecting the photosynthetically active area of the crop which could affect grain protein content (GPC) and breadmaking parameters. Nitrogen (N) fertilization is required for achieving high yields and quality in wheat but can exert a profound effect on disease development and fungicide efficacy. The active ingredient fluxapyroxad, belonging to the carboxamides chemical group, not only control fungal pathogens and reduce disease progression but also, might increase green leaf area duration of the crop. We evaluated the effect of fungicide applications containing a carboxamide, in a mixture with triazole and strobilurin (TSC), above a double-mixture (triazole and strobilurin) (TS) under three N rates, on tan spot severity, healthy area duration (HAD), flag leaf healthy area duration (FLHAD) and grain yield. We also assessed its impact on GPC, wet gluten content, loaf volume and dough rheological parameters in wheat. Two field experiments were conducted during 2014 and 2015 in a split-split plot design with three fungicide treatments as main plots and three N fertilization rates as sub-plots using a susceptible cultivar (Baguette 11, Nidera). Treatment TSC significantly reduced the area under disease progress curve (AUDPC) and this was associated with increased HAD and FLHAD resulting in higher yields when compared to the TS treatment and the untreated control. The AUDPC values were lower with higher N rates in the untreated plots. The GPC and wet gluten content increased in untreated plots under 0 kg N ha −1 and 70 kg N ha −1 rate and was reduced following fungicide applications, however, this was reverted with the maximum N rate (140 kg N ha −1 ). Increases in GPC and wet gluten content in the untreated plots did not improve loaf volume and breadmaking parameters of wheat which only enhanced following fungicide application and N fertilization. [ABSTRACT FROM AUTHOR]

The ascomycete Pyrenophora tritici-repentis ( Ptr ) is an important fungal pathogen worldwide that causes tan spot of wheat. The fungus is self-fertile because each isolate contains both mating type ( MAT ) idiomorphs. In this work, we developed knockouts of the MAT genes in Ptr and tested fertility of the knockout strains and outcrossing between the knockout strains carrying the opposite mating type. The fungal strains with deletions of either MAT1-1 - 1 or MAT1-2 - 1 did not form mature pseudothecia making them functionally heterothallic. The cross between the heterothallic strains of the same isolate (86–124) was fully fertile with the only difference compared to the homothallic wild type strain being the slightly lower percentage of pseudothecium formation. However, the cross between 86–124 (race 2, ToxA -containing isolate) and DW5 (race 5, ToxB -containing isolate) was partially fertile and had fewer mature pseudothecia. Furthermore, most mature asci produced only two or four instead of eight functional ascospores. A collection of ascospores from this cross was obtained and genotyped for the presence of the ToxA , ToxB and MAT genes as well as simple sequence repeat markers. The segregation of these genes and markers and recombination of different allele types at these loci was observed. This work clearly demonstrates that the fungus requires both MAT genes for sexual production and can undergo outcrossing and sexual recombination. It also establishes a new and practical way for further characterizing fungal virulence in Ptr through the development of segregating fungal populations and subsequent genetic analysis. [ABSTRACT FROM AUTHOR]

Key message: Tan spot susceptibility is conferred by multiple interactions of necrotrophic effector and host sensitivity genes. Abstract: Tan spot of wheat, caused by Pyrenophora tritici-repentis, is an important disease in almost all wheat-growing areas of the world. The disease system is known to involve at least three fungal-produced necrotrophic effectors (NEs) that interact with the corresponding host sensitivity ( S) genes in an inverse gene-for-gene manner to induce disease. However, it is unknown if the effects of these NE- S gene interactions contribute additively to the development of tan spot. In this work, we conducted disease evaluations using different races and quantitative trait loci (QTL) analysis in a wheat recombinant inbred line (RIL) population derived from a cross between two susceptible genotypes, LMPG-6 and PI 626573. The two parental lines each harbored a single known NE sensitivity gene with LMPG-6 having the Ptr ToxC sensitivity gene Tsc1 and PI 626573 having the Ptr ToxA sensitivity gene Tsn1. Transgressive segregation was observed in the population for all races. QTL mapping revealed that both loci ( Tsn1 and Tsc1) were significantly associated with susceptibility to race 1 isolates, which produce both Ptr ToxA and Ptr ToxC, and the two genes contributed additively to tan spot susceptibility. For isolates of races 2 and 3, which produce only Ptr ToxA and Ptr ToxC, only Tsn1 and Tsc1 were associated with tan spot susceptibility, respectively. This work clearly demonstrates that tan spot susceptibility in this population is due primarily to two NE- S interactions. Breeders should remove both sensitivity genes from wheat lines to obtain high levels of tan spot resistance. [ABSTRACT FROM AUTHOR]

Tan spot or yellow (leaf) spot disease of wheat (Triticum spp.) is caused by Pyrenophora tritici-repentis, a necrotrophic fungal pathogen that is widespread throughout the main wheat-growing regions in the world. This disease is currently the single most economically important crop disease in Australia. In this study, a real-time quantitative polymerase chain reaction (qPCR) assay was developed as a diagnostic tool to detect the pathogen on wheat foliar tissue. A multicopy locus (PtrMulti) present in the P. tritici-repentis genome was assessed for its suitability as a qPCR probe. The primer pair PtrMulti_F/R that targets the region was evaluated with respect to species specificity and sensitivity. A PtrMulti S YBR qPCR assay was developed and proved to be suitable for the identification and relative quantification of P. tritici-repentis with a detection limit of DNA levels at <0.1 pg. Variation of the PtrMulti copy number between the geographical representatives of P. tritici-repentis strains examined was minimal, with the range of 63 to 85 copies per genome. For naturally infected wheat field samples, the incidence of P. tritici-repentis DNA on leaves quantified by qPCR varied up to 1,000-fold difference in the concentration, with a higher incidence of DNA occurring on the lower canopy for most of the growth stages examined. At the early growth stages, qPCR assay was able to detect P. tritici-repentis DNA on the younger leaves in the absence of visible tan spot lesions. These results demonstrate the potential of PtrMulti probe to be used for early detection and rapid screening of tan spot disease on wheal plants. [ABSTRACT FROM AUTHOR]

Objectives: The fungus Pyrenophora tritici-repentis is a major pathogen of wheat worldwide, causing the leaf spotting disease tan spot. To best inform approaches for plant genetic resistance, an understanding of the biology and pathogenicity mechanisms of this fungal pathogen is essential. Here, intracellular and extracellular proteins of P. triticirepentis were extracted, and peptides analysed via high-resolution mass spectrometry. Our objective was to generate a useful proteomics resource for P. tritici-repentis. A survey of proteins secreted by the pathogen into culture filtrate is especially useful, as these are likely to come in direct contact with the wheat host and may play important roles in infection/pathogenicity. The peptide data presented herein, has also been used to successfully verify and refine in silico predicted P. tritici-repentis gene annotations, through the validation of alternative splicing and reading frame shifts. Data description: The data sets presented consist of peptide spectra of the extracellular and intracellular proteomes of three P. tritici-repentis isolates. Peptide matches to translated transcripts of the North American reference isolate Pt- 1C-BFP are also provided. [ABSTRACT FROM AUTHOR]

Pyrenophora tritici-repentis (Ptr) is a destructive fungal pathogen of wheat worldwide. In addition to wheat, Ptr has been isolated from various other hosts in the family Poaceae, yet the nature of its interaction with those hosts is unknown. The Ptr-barley relationship was explored and the existence of a specific interaction between Ptr and barley is described for the first time; symptom development on several barley genotypes was evaluated in bioassays and by toxin infiltration into barley leaves. Ptr ToxB-producing isolates of the fungus were able to cause significant damage when inoculated onto certain barley genotypes, and Ptr ToxB was able to induce chlorosis in a highly selective manner when infiltrated into those same genotypes. Ptr-barley specificity is subtle and can break with slight changes in temperature after infection. To understand the infection process in barley, a cytological analysis and in planta fungal biomass estimation using quantitative PCR were performed. The fungus penetrates through the host epidermal cells and advances to colonize the mesophyll layer intercellularly, with the infection process on barley closely resembling that on wheat. Here, evidence is provided for a specific interaction between barley and Ptr, expanding understanding of Ptr host specificity and breaking the assumption that the highest level of specificity seen with Ptr is restricted to particular genotypes of the wheat host. [ABSTRACT FROM AUTHOR]

Yellow spot (caused by Pyrenophora tritici-repentis) is a major foliar disease in wheat (Triticum aestivum) that has become more serious in recent years, possibly because of climate change. A major quantitative trait locus (QTL) located on the short arm of wheat chromosome 2B explaining 30-40% of the phenotypic variance has been identified as responsible for resistance to Australian yellow spot isolates, which reportedly produce mostly the ToxA effector. The closest marker linked to this QTL was a DArT marker not easy to use in large-scale selections, whereas the closest PCR-based marker available (2.7 cM) was too far away for reliably tagging the locus in wheat breeding. We therefore undertook studies to develop more closely linked and user-friendly markers for this major QTL. Forty-one new markers either synthesised from DArT markers or identified from the GrainGene database were assessed. From these, we developed a new PCR-based marker (Rfsts1), located 0.3 cM away from the major QTL. This is the first suitable marker for marker-assisted selection for yellow spot resistance in Australian wheat-breeding programs. [ABSTRACT FROM AUTHOR]

Wheat is one of the most important cultivated cereals worldwide. In Uruguay, the area increased from 153.000 ha to 453.000 ha between 2004 and 2012, nowadays representing 80% of the total winter crops area. As the high area of the crop, is common planting wheat in a field with wheat as previous winter crop (“wheat after wheat”). This practice leads to a high inoculum pressure of necrotrophic pathogens which guarantees disease inoculation mainly of Pyrenophora tritici-repentis (tan spot—TS) and Zymoseptoria tritici (septoria leaf blotch—SLB). There is strong evidence that integrated crop management practices such as nitrogen (N) fertilization, genetic resistance to leaf diseases and fungicides could mitigate yield losses associated with monoculture. However, the impacts of integrated technologies based on actual field data have not been reported before. We based our study in an on-farm wheat yield and management database to assess the previous winter crop effect on wheat yield under no-till systems. This database corresponds to a set of farmers grouped in CREA (Consorcio Regional de Experimentación Agrícola). A complete database of 1292 no-till wheat fields was analyzed. The effect of previous winter crop on yield and the impact of different technologies were estimated based on two approaches: (i) yield quartile analysis and (ii) yield frontier analysis. The crop rotation had a significant impact on yield. The practice of growing “wheat after wheat” was associated with a yield loss of ca 500 kg ha −1 . The selection of a diseases resistant cultivar under “wheat after wheat” fields increases yields in ≈700 kg ha −1 . The percentage of fields with an efficiency higher than 80% improved from 49 to 77% when a resistant cultivar to TS and SLB was selected, and when N fertilizer was applied earlier and in higher rates. Unexpectedly, only 18% of the “wheat after wheat” fields are applying these two technologies in scenarios under high inoculum pressure. This study, based in on-farm data, highlights the relevance of integrated disease management, and remarks the potential of this approach to minimize the interference of foliar diseases in fields with high inoculum pressure of stubble-borne pathogens. [ABSTRACT FROM AUTHOR]

The necrotrophic fungal pathogen Pyrenophora tritici-repentis causes tan spot, a major disease of wheat, throughout the world. The proteinaceous effector ToxA is responsible for foliar necrosis on ToxA-sensitive wheat genotypes. The single copy ToxA gene was deleted from a wild-type race 1 P. tritici-repentis isolate via homologous recombination of a knockout construct. Expression of the ToxA transcript was found to be absent in transformants ( toxa), as was ToxA protein production in fungal culture filtrates. Plant bioassays were conducted to test transformant pathogenicity. The toxa strains were unable to induce necrosis on ToxA-sensitive wheat genotypes. To our knowledge, this is the first demonstration of a targeted gene knockout in P. tritici-repentis. The ability to undertake gene deletions will facilitate the characterization of other pathogenicity effectors of this economically significant necrotroph. [ABSTRACT FROM AUTHOR]

Tan spot is a destructive foliar disease of wheat caused by the fungal pathogen Pyrenophora tritici-repentis. Recently, tan spot has become a serious problem in the northern parts of Iran, where it causes severe yield losses. The objective of this study was to identify the physiological races of P. tritici-repentis in Iran, and to test isolates from this country for the presence of the toxin-encoding genes ToxA and ToxB. In total, 184 isolates were collected from two provinces, Golestan and Mazandaran, near the Caspian Sea. The virulence of 48 of these isolates was evaluated on four differential wheat genotypes. Race 1 was predominant and represented 90% of the tested isolates, while the remaining 10% were classified as race 2. No other races were identified. ToxA- and ToxB-specific primers were used in a PCR-based analysis to detect the presence of these genes in the Iranian isolates. The ToxA gene was amplified from all of the isolates evaluated, while no amplicon was obtained from any of the isolates with the ToxB-specific primers. The presence of ToxA and absence of ToxB is consistent with the race designation of the isolates. The ToxA sequence from 10 isolates selected, based on geographical origin, was found to be identical, and also shared 100% identity with other ToxA sequences from P. tritici-repentis in GenBank. This is the first study of the race structure of P. tritici-repentis in Iran. [ABSTRACT FROM AUTHOR]

Abstract: Tan spot, caused by Pyrenophora tritici-repentis, is an important foliar disease of wheat. In the present study, a gene named glucanase gene (GLU1) encoding a putative exo-1,3-β-glucanase was cloned from a race five isolate of P. tritici-repentis. Transcription profile analysis of the GLU1 gene showed a carbon source control of the accumulation of transcript, which is strongly induced in minimal medium but depressed in rich medium. A time-course study of the infection process of the wild-type isolate on a susceptible wheat genotype revealed that the transcript level of GLU1 increased more than 8000-fold 8 h after inoculation. To study its potential function in pathogenicity, GLU1 was silenced via a sense and antisense mediated silencing mechanism. One transformant named C1 showed significantly reduced growth and sporulation relative to the wild-type. Cytological analysis of the infection revealed that C1 produced significantly lower numbers of germ tubes and appressoria than the wild-type strain on susceptible wheat leaves. This strain, as well as another two transformants, caused significantly less disease symptoms relative to the wild-type after inoculation onto a susceptible wheat genotype. These results indicate that GLU1 contributes to the development and virulence of P. tritici-repentis. [Copyright &y& Elsevier]

Tan spot is one of the main diseases of wheat in Brazil reducing grain yield up to 80%. Although the lesion expansion is an important component of the epidemics, there are few studies on its control by curative sprays of fungicide. To know how different fungicides may control lesion expansion and to improve disease management, four assays were carried out at the Universidade de Passo Fundo (UPF) in 2011. All assays were organized as randomized blocks, with four replicates, inside a growth chamber with control of light and temperature. In two assays a triazole (propiconazole) and a strobylurin (azoxystrobin) fungicides, as well as their mixture, were sprayed from one to 12 day intervals after inoculation of the wheat cultivars 'Fundacep Horizonte' and 'Quartzo'. Based upon measurements of the lesion size, the strobylurin did not reduce the rate of lesion growth (0.176 to 0.180 mm².day-1) in comparison to the non-sprayed control (0.175 to 0.184 mm².day-1), whereas the triazole (0.080 mm².day-1) and the fungicide mix (0.060 to 0.080 mm².day-1) did it if sprayed within 10 or 12 days after inoculation. In two other assays, commercial fungicides (epoxiconazole, propiconazole, tebuconazole, azoxystrobin, pyraclostrobin, cyproconazole + azoxystrobin, epoxiconazole + pyraclostrobin, protioconazole + trifloxystrobin and tebuconazole + trifloxystrobin) were sprayed onto plants at three, five and eight days after inoculation. Spraying of the fungicides epoxiconazole, propiconazole, and protioconazole + trifloxystrobin at fi ve days reduced the rate of lesion expansion (0.07 to 0.14 mm².day-1) over the control non-sprayed plants (0.29 mm².day-1). Fungicide applications eight days had no effect on the rate of progress of lesions. The final lesion size was smaller (3.76 to 5.89 mm²) on plants sprayed with tebuconazole + trifloxystrobin, protioconazole + trifloxystrobin, tebuconazol, epoxiconazole + pyraclostrobin, and propiconazole, but higher (8.46 to 11.70 mm²) for cyproconazole + azoxystrobin, azoxystrobin, epoxiconazole, and pyraclostrobin, which did not differ from the non-sprayed control. These results show how diffi cult is to limit tan spot increase after disease establishment and indicate that is management requires the adoption of preventive control strategies. [ABSTRACT FROM AUTHOR]

Tan spot, caused by Pyrenophora triticirepentis, is an important disease of wheat (Triticum aestivum L.) worldwide. Pathogenic races of P. tritici-repentis have been identified on the basis of their ability to induce tan necrosis and/or chlorosis symptoms on differential wheat genotypes. A group of isolates of P. triticirepentis collected from Arkansas did not fit into the current race classification system because they lack the ToxA gene. In this study, 535 spring wheat accessions were inoculated with a representative novel isolate (AR CrossB10) of P. tritici-repentis from Arkansas. An association mapping approach and 832 polymorphic diversity array technology markers were used to identify quantitative trait loci (QTL) associated with resistance to the isolate AR CrossB10. Two models (QK1 and QK2) with the least mean square difference were selected among nine linear regression models tested, and 11 QTL involved in resistance to AR CrossB10 were identified, which are located on chromosomes 1A, 1D, 2B, 2D, 6A, and 7A. The results suggest that multiple disease resistance genes also are clustered around a few of the significant markers and will be useful for wheat breeding programs and for search of candidate genes. [ABSTRACT FROM AUTHOR]

Tan spot of wheat caused by Drechslera tritici-repentis was identified for the first time in the Grand-Duchy of Luxembourg (GDL) in 1999 on the basis of morphological characters. In order to optimize disease control measures in this country, tillage methods, cultivar resistance, and fungicide effects were investigated during 1999-2009 in four sites. Over this period, only three years (i.e. 1999, 2000, and 2009) with epidemic outbreak were recorded. Field experiments showed a significant difference in disease severity between sites (P < 0.001), cultivars (P < 0.0001) and years (P < 0.001). In years with epidemic outbreaks, the interaction of cultivars with non-inversion tillage, intensive winter wheat production, and favorable weather conditions caused an early outbreak of the disease and a significant severity at growth stage 83 (early dough). Non-inversion tillage was found to be a major factor increasing tan spot severity compared with conventional tillage. Furthermore, the analysis revealed that disease severity was related to the cultivar's susceptibility. For cultivars with similar phenology, disease severity beetween the most and the least susceptible cultivars differed by a factor of two tofour. The study also showed that nofungicide (mix of triazoles and strobilurins) effect was observed in the epidemic years, except in 2000. [ABSTRACT FROM AUTHOR]

Wheat tan spot produced by Drechslera tritici repentis (Died.) Shoemaker fungus is a foliar disease spread in many areas of the world where wheat is cultivated; having great economic importance due to loses that can be produced at great attack intensities. This pathogen is present in Romania by about 15 years. In Banat region was first reported in 2007, with the suspicion that the fungus was present already before in wheat crops. The harvest loses produced by this pathogen are in direct relationship with the inoculum amount, the resistance of the cultivated variety, with the climatic conditions and with the wheat plants phenophase at the moment of the infections. In 2011 there have been monitored 13 winter wheat varieties, respectively 11 varieties of common wheat (Apache, Kalango, Azimut, Soissons, Renan, Karolinum, Esperia, Bilancia, Centauro, Sagittario and Alcione) and 2 varieties of durum wheat (Normanno and Maestrale). The climatic conditions from the spring of 2011 have influenced positively the pathogeny of Drechslera tritici repentis (Died.) Shoemaker fungus. The virulence of the pathogen was comprised between 45% and 75%. The most sensitive variety from the trial was Apache (control), where the attack intensity was 75%. The attack severity in the Italian varieties was between 48.33% (Esperia) and 66.66% (Normanno and Centauro). The lowest virulence from the trial was registered in the variety Kalango (I% = 45%). Due to the favourable climatic conditions, the infection has been spread to the flag leaf too. The flag leaf was affected in proportion of 15% (Maestrale and Bilancia varieties) and 33.33% (variety Apache). At the moment when the infection reaches the flag leaf the grains are susceptible to the infection. The evolution of Drechslera tritici repentis (Died.) Shoemaker fungus was assessed by the use of AUDPC (area under the disease progress curve). The greatest values of AUDPC have been registered in the varieties Centauro (1370.56), Renan (1359.84), Apache (1333.28), Normanno (1306.56), and the lowest values in the varieties Kalango (917.28), Azimut (954.56) and Esperia (959.84). The values of AUDPC are strongly correlated with the values of intensity registered in the trial field. [ABSTRACT FROM AUTHOR]

Wheat sharp eyespot (WSE) caused by Rhizoctonia cerealis is one of the most important diseases on wheat in China. In this study, a pair of PCR primers was designed based on the sequence of a DNA region amplified by the microsatellite primer M13. The primer pair amplified a 272 bp fragment from all R. cerealis isolates collected from wheat stems at different locations in different years, but not from any other fungal species tested. A real-time PCR assay using this primer pair was developed to detect early and suspected infection of R. cerealis on wheat stems in the field. The real-time PCR assay established here could help verifying the presence of R. cerealis in stem-base diseased wheat plants, thus assisting growers in choosing the proper fungicides. [ABSTRACT FROM AUTHOR]