Powdery mildew resistance of barley in Southern Dagestan

Background.The most effective way of protecting crops from diseases and pests is the breeding and cultivation of resistant varieties. The hydrothermal regime in the southern plains of Dagest an favors damage to barley plant s by the causative agent of powdery mildew. The high level of disease progress observed annually helps to reliably assess the resistance of collection accessions to the pathogen.Materials and methods.The research material included 1361 barley accessions (570 improved cultivars and 791 landraces) of different ecogeographic origin and growth habit. Field experiments were launched concurrently with winter sowing. Powdery mildew resistance was scored during the heading period and in the milk ripeness phase using a point scale. Each accession was assessed for at least three years.Results and conclusions.The results of a long-term study disclosed a significant intraspecific variability of barley collection accessions in their resistance to powdery mildew. A significant part of the studied barley accessions (63.1%) appeared susceptible to the pathogen. The occurrence frequency of disease-resistant accessions was 11.0%, while those with medium resistance reached 25.9%. Among the landraces, four resistant accessions from the Abyssinian, West Asian and Mediterranean centers of crop origin were identified. Seventeen barley varieties resistant to powdery mildew (predominantly originated from Western Europe) are recommended for use in breeding for immunity.

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Evaluation of Powdery Mildew Resistance in Hydrangea macrophylla

Journal of Environmental Horticulture ◽

10.24266/0738-2898-29.2.60 ◽

2011 ◽

Vol 29 (2) ◽

pp. 60-64 ◽

Cited By ~ 4

Author(s):

Mark T. Windham ◽

Sandra M. Reed ◽

Margaret T. Mmbaga ◽

Alan S. Windham ◽

Yonghao Li ◽

...

Keyword(s):

Powdery Mildew ◽

Powdery Mildew Resistance ◽

Late Summer ◽

Sources Of Resistance ◽

Mildew Resistance ◽

Potted Plants ◽

Hydrangea Macrophylla ◽

Erysiphe Polygoni ◽

High Level ◽

Moderately Resistant

Abstract Powdery mildew, Erysiphe polygoni DC, can be a significant problem on Hydrangea macrophylla (Thunb.) Ser. in the landscape in late summer to fall and during greenhouse propagation or production of potted plants. Because very little information related to sources of resistance is available, 90 H. macrophylla cultivars were evaluated for resistance to powdery mildew over a 3-year period. This included 69 H. macrophylla ssp. macrophylla and 18 H. macrophylla ssp. serrata (Thunb.) Makino cultivars, along with three cultivars that are hybrids between the two subspecies. Significant differences among cultivars to powdery mildew were found in all three study years. Three cultivars, ‘Amagi Amacha’, ‘Shirofuji’ and ‘Veitchii’, were among the most resistant each year. ‘Diadem’, ‘Komachi’, and ‘Omacha’ were highly resistant in 2006 and 2008, but only moderately resistant in 2007. ‘Komachi’ and ‘Shirofuji’ were considered unsuitable for breeding purposes as they do not appear to produce fertile flowers. ‘Veitchii’ was the only member of H. macrophylla ssp. macrophylla with a high level of powdery mildew resistance; while all other resistant cultivars were members of H. macrophylla ssp. serrata, not all members of this subspecies are resistant. Results of this study will be useful in breeding powdery mildew resistant H. macrophylla.

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Field Experiments with DH-Lines in Barley with ML-o Powdery Mildew Resistance

The Impact of Biotechnology on Agriculture - Current Plant Science and Biotechnology in Agriculture ◽

10.1007/978-94-009-0587-0_8 ◽

1990 ◽

pp. 99-104

Author(s):

Åsmund Bjørnstad

Keyword(s):

Powdery Mildew ◽

Field Experiments ◽

Powdery Mildew Resistance ◽

Mildew Resistance ◽

Dh Lines

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Accumulation of a Protein Associated with Plant Defense in Powdery Mildew Resistant Dogwood (Cornus florida)

Journal of Environmental Horticulture ◽

10.24266/0738-2898-24.2.115 ◽

2006 ◽

Vol 24 (2) ◽

pp. 115-118

Author(s):

M.T. Mmbaga ◽

F.J. Avila ◽

E.F. Howard ◽

E.L. Myles

Keyword(s):

Powdery Mildew ◽

Plant Defense ◽

Powdery Mildew Resistance ◽

Cornus Florida ◽

Defense Proteins ◽

Mildew Resistance ◽

Flowering Dogwood ◽

Plant Defense Proteins ◽

Powdery Mildew Pathogen ◽

High Level

Abstract This study was conducted to better understand the nature of powdery mildew resistance in flowering dogwood (Cornus florida L.) and in particular to determine if inducible plant defense proteins are associated with powdery mildew resistance. Results from this study showed an accumulation of a new protein in resistant plants, but not in susceptible plants that were challenged with powdery mildew pathogen (Erysiphe (Sect. Microsphaera) pulchra). The protein accumulated in a high level in the resistant selections at 48 hr after inoculation with the pathogen and that was consistent with the production of pathogenesis related (PR) proteins. The protein was characterized as having an isoelectric point of 7.5 ± 0.5 and molecular weight of 18 ± 2 KD. Partial sequence analysis of this protein revealed homology with PR-10 protein associated with drought resistance in potato and was analogous to other proteins related to resistance in other crops. Repeated analysis showed similar results and suggested that a biochemical mode of resistance involving plant defense proteins may be associated with powdery mildew resistance in flowering dogwood.

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Inheritance of Powdery Mildew Resistance in Sugar Beet Derived from Beta vulgaris subsp. maritima

Plant Disease ◽

10.1094/pdis.2001.85.6.627 ◽

2001 ◽

Vol 85 (6) ◽

pp. 627-631 ◽

Cited By ~ 25

Author(s):

R. T. Lewellen ◽

J. K. Schrandt

Keyword(s):

Powdery Mildew ◽

Sugar Beet ◽

Beta Vulgaris ◽

Powdery Mildew Resistance ◽

Major Gene ◽

Mildew Resistance ◽

Breeding Lines ◽

Erysiphe Polygoni ◽

Moderate Resistance ◽

High Level

Powdery mildew of sugar beet (Beta vulgaris), caused by Erysiphe polygoni, was introduced into North American in 1974. Since then, chemical control has been needed. Moderate resistance of a slow-mildewing type is known and has been used commercially. High resistance was identified recently in B. vulgaris subsp. maritima accessions WB97 and WB242 and has been backcrossed into sugar beet breeding lines. These enhanced lines were used as sources of powdery mildew resistance to determine the inheritance of resistance. Analyses of segregating testcross families showed that resistance from both sources is inherited as a single, dominant, major gene. The gene symbol Pm is proposed for the resistant allele. The allelism of the resistance from the two wild beet sources was not determined. Pm conditions a high level of resistance, but disease developed on matured leaves late in the season. This late development of mildew on lines and the slow-mildewing trait in susceptible, recurrent lines tended to obfuscate discrete disease ratings.

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Physiological Changes in Barley mlo-11 Powdery Mildew Resistance Conditioned by Tandem Repeat Copy Number

International Journal of Molecular Sciences ◽

10.3390/ijms21228769 ◽

2020 ◽

Vol 21 (22) ◽

pp. 8769

Author(s):

Cynthia Ge ◽

Paula Moolhuijzen ◽

Lee Hickey ◽

Elzette Wentzel ◽

Weiwei Deng ◽

...

Keyword(s):

Powdery Mildew ◽

Copy Number ◽

Powdery Mildew Resistance ◽

Binding Motif ◽

Small Interfering Rnas ◽

Mildew Resistance ◽

Barley Powdery Mildew ◽

Highly Expressed Genes ◽

Normal Gene ◽

High Level

Wild barley accessions have evolved broad-spectrum defence against barley powdery mildew through recessive mlo mutations. However, the mlo defence response is associated with deleterious phenotypes with a cost to yield and fertility, with implications for natural fitness and agricultural productivity. This research elucidates the mechanism behind a novel mlo allele, designated mlo-11(cnv2), which has a milder phenotype compared to standard mlo-11. Bisulphite sequencing and histone ChIP-seq analyses using near-isogenic lines showed pronounced repression of the Mlo promoter in standard mlo-11 compared to mlo-11(cnv2), with repression governed by 24 nt heterochromatic small interfering RNAs. The mlo-11(cnv2) allele appears to largely reduce the physiological effects of mlo while still endorsing a high level of powdery mildew resistance. RNA sequencing showed that this is achieved through only partly restricted expression of Mlo, allowing adequate temporal induction of defence genes during infection and expression close to wild-type Mlo levels in the absence of infection. The two mlo-11 alleles showed copy number proportionate oxidase and peroxidase expression levels during infection, but lower amino acid and aromatic compound biosynthesis compared to the null allele mlo-5. Examination of highly expressed genes revealed a common WRKY W-box binding motif (consensus ACCCGGGACTAAAGG) and a transcription factor more highly expressed in mlo-11 resistance. In conclusion, mlo-11(cnv2) appears to significantly mitigate the trade-off between mlo defence and normal gene expression.

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Transgenic Endochitinase Producing Grapevine for the Improvement of Resistance to Powdery Mildew (Uncinula necator)

10.32747/1994.7568766.bard ◽

1994 ◽

Author(s):

Avichai Perl ◽

Bruce I. Reisch ◽

Ofra Lotan

Keyword(s):

Transgenic Plants ◽

Powdery Mildew ◽

Trichoderma Harzianum ◽

Field Experiments ◽

Powdery Mildew Resistance ◽

Constitutive Expression ◽

Cultural Control ◽

Economic Losses ◽

Uncinula Necator ◽

Mildew Resistance

The original objectives are listed below: 1. Design vectors for constitutive expression of endochitinase from Trichoderma harzianum strain P1. Design vectors with signal peptides to target gene expression. 2. Extend transformation/regeneration technology to other cultivars of importance in the U.S. and Israel. 3. Transform cultivars with the endochitinase constructs developed as part of objective 1. A. Characterize foliar powdery mildew resistance in transgenic plants. Background of the topic Conventional breeding of grapevines is a slow and imprecise process. The long generation cycle, large space requirements and poor understanding of grapevine genetics prevent rapid progress. There remains great need to improve existing important cultivars without the loss of identity that follows from hybridization. Powdery mildew (Uncinula necator) is the most important fungal pathogen of grapevines, causing economic losses around the world. Genetic control of powdery mildew would reduce the requirement for chemical or cultural control of the disease. Yet, since the trait is under polygenic control, it is difficult to manipulate through hybridization and breeding. Also, because grapevines are heterozygous and vegetatively propagated cultivar identity is lost in the breeding process. Therefore, there is great need for techniques to produce transgenic versions of established cultivars with heterologous genes conferring disease resistance. Such a gene is now available for control of powdery mildew of grapevines. The protein coded by the Endochitinase gene, derived from Trichoderma harzianum, is very effective in suppressing U. necator growth. The goal of this proposal is to develop transgenic grapevines with this antifungal gene, and to test the effect of this gene on resistance to powdery mildew. Conclusions, achievements and implications Gene transfer technology for grape was developed using commercial cultivars for both wine and table grapes. It paved the way for a new tool in grapevine genetic studies enabling the alteration of specific important traits while maintaining the essential features of existing elite cultivars. Regeneration and transformation technologies were developed and are currently at an advanced stage for USA wine and Israeli seedless cultivars, representing the cutting edge of grape genetic engineering studies worldwide. Transgenic plants produced are tested for powdery mildew resistance in greenhouse and field experiments at both locations. It is our ultimate goal to develop transgenic grapes which will be more efficient and economical for growers to produce, while also providing consumers with familiar products grown with reduced chemical inputs.

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