scholarly journals High Temperature Enhances the Resistance of Cultivated African Rice, Oryza glaberrima, to Bacterial Blight

Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 380-387 ◽  
Author(s):  
Gerbert Sylvestre Dossa ◽  
Ricardo Oliva ◽  
Edgar Maiss ◽  
Casiana Vera Cruz ◽  
Kerstin Wydra
Keyword(s):  
High Temperature ◽  
Resistance Genes ◽  
Broad Spectrum ◽  
Host Resistance ◽  
Bacterial Blight ◽  
The Philippines ◽  
Oryza Glaberrima ◽  
Pathogen Invasion ◽  
Broad Spectrum Resistance ◽  
Wide Range

Rice bacterial blight (BB) is caused by Xanthomonas oryzae pv. oryzae and is responsible for substantial yield loss worldwide. Host resistance remains the most feasible control measure. However, pathogen variability leads to the failure of certain resistance genes to control the disease, and climate change with high amplitudes of heat predisposes the host plant to pathogen invasion. Due to pressure in natural selection, landrace species often carry a wide range of unique traits conferring tolerance of stress. Therefore, exploring their genetic background for host resistance could enable the identification of broad-spectrum resistance to combined abiotic and biotic stresses. Nineteen Oryza glaberrima accessions and O. sativa rice variety SUPA were evaluated for BB resistance under high temperature (35 and 31°C day and night, respectively) using 14 X. oryzae pv. oryzae strains originated from the Philippines. Under normal temperature, most of the accessions showed resistance to 9 strains (64.3%) and accession TOG6007 showed broad-spectrum resistance to 12 strains (85.7%). Under high temperature, most accessions showed a reduction in BB disease, whereas, accession TOG5620 showed disease reduction from all the X. oryzae pv. oryzae strains under high temperature. Molecular characterization using gene-based and linked markers for BB resistance genes Xa4, xa5, Xa7, xa13, and Xa21 revealed the susceptible alleles of Xa4, xa5, xa13, and Xa21 in O. glaberrima. However, no allele of Xa7 was detected among O. glaberrima accessions. Our results suggest that O. glaberrima accessions contain a BB resistance different from the Xa gene type. Genome-wide association mapping could be used to identify quantitative trait loci that are associated with BB resistance or combined BB resistance and high-temperature tolerance.

scholarly journals Addicted? Reduced host resistance in populations with defensive symbionts

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160778 ◽  
Author(s):  
Julien Martinez ◽  
Rodrigo Cogni ◽  
Chuan Cao ◽  
Sophie Smith ◽  
Christopher J. R. Illingworth ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Insect Resistance ◽  
Resistance Genes ◽  
Host Resistance ◽  
Major Effect ◽  
Insect Host ◽  
Insect Genome ◽  
Resistant Allele ◽  
Wide Range ◽  
Evolution Of Resistance

Heritable symbionts that protect their hosts from pathogens have been described in a wide range of insect species. By reducing the incidence or severity of infection, these symbionts have the potential to reduce the strength of selection on genes in the insect genome that increase resistance. Therefore, the presence of such symbionts may slow down the evolution of resistance. Here we investigated this idea by exposing Drosophila melanogaster populations to infection with the pathogenic Drosophila C virus (DCV) in the presence or absence of Wolbachia , a heritable symbiont of arthropods that confers protection against viruses. After nine generations of selection, we found that resistance to DCV had increased in all populations. However, in the presence of Wolbachia the resistant allele of pastrel —a gene that has a major effect on resistance to DCV—was at a lower frequency than in the symbiont-free populations. This finding suggests that defensive symbionts have the potential to hamper the evolution of insect resistance genes, potentially leading to a state of evolutionary addiction where the genetically susceptible insect host mostly relies on its symbiont to fight pathogens.

Pathogenic variation of powdery mildew of barley in Western Australia

1992 ◽  
Vol 43 (1) ◽  
pp. 79 ◽  
Author(s):  
KC Chan ◽  
WJR Boyd
Keyword(s):  
Natural Selection ◽  
Powdery Mildew ◽  
Western Australia ◽  
Resistance Genes ◽  
Host Resistance ◽  
High Frequency ◽  
Natural Field ◽  
Barley Cultivars ◽  
Pathogenic Variation

The identity and estimated frequency of genes for virulence in natural field populations of Endsiphe grarninis f.sp. hordei is reported in Western Australia. Fifteen genes were identified, five of which occurred at relatively high frequency. Only two of those identified (Vk and Vg) can be accounted for on the basis of natural selection due to the presence of corresponding resistance genes in commercial barley cultivars. Implications for breeding for host resistance in Western Australia are discussed.

scholarly journals Virulence Dynamics and Regional Structuring of Puccinia striiformis f. sp. tritici in France Between 1984 and 2009

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Claude de Vallavieille-Pope ◽  
Sajid Ali ◽  
Marc Leconte ◽  
Jérôme Enjalbert ◽  
Marc Delos ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Host Resistance ◽  
Evolutionary Biology ◽  
Puccinia Striiformis ◽  
Regional Level ◽  
The North ◽  
Pathogen Populations ◽  
Successive Acquisition ◽  
Selection Of

Understanding of long-term virulence dynamics of pathogen populations in response to host resistance gene deployment is of major importance for disease management and evolutionary biology. We monitored the virulence dynamics of Puccinia striiformis f. sp. tritici, the causal agent of wheat stripe rust, over 25 years in France. Virulence dynamics was explained by estimates of area associated with resistance genes carried by farmers' cultivars. The epidemics assessed through disease severity significantly correlated with the number of P. striiformis f. sp. tritici isolates collected each year, used to describe virulence dynamics. In the south, the dominance of the Mediterranean pathotype 6E16 and the cultivation of a susceptible cultivar were associated with an epidemic from 1997 to 1999. In the north, five epidemics occurred due to successive acquisition of virulence to the resistance genes Yr7, Yr6, Yr9, Yr17, and Yr32, either by acquisition of the virulence in the previous dominant pathotype or by incursion or selection of one or two new pathotypes. Frequency of pathotypes with Vr7 and Vr6 declined with the reduction in the cultivation of corresponding Yr gene cultivars, whereas the virulence Vr9 persisted longer than the cultivation of Yr9 cultivars. Although the first pathotypes carrying Vr9 decreased, this virulence persisted in other pathotypes even in the absence of Yr9 cultivars. At the regional level, Yr9 cultivars in the north caused a shift from high Vr6 frequency to high Vr9 frequency whereas, in the central region, where Yr9 cultivars were rare, Vr6 remained prevalent.

scholarly journals Advances in Plant−Nematode Interactions with Emphasis on the Notorious Nematode Genus Meloidogyne

2019 ◽  
Vol 109 (12) ◽  
pp. 1988-1996 ◽  
Author(s):  
Isgouhi Kaloshian ◽  
Marcella Teixeira
Keyword(s):  
Resistance Genes ◽  
Host Resistance ◽  
Parasitic Nematodes ◽  
Agricultural Systems ◽  
Plant Parasitic Nematodes ◽  
Molecular Pattern ◽  
Plant Nematode ◽  
Durable Host Resistance ◽  
Ubiquitous Presence ◽  
Plant Parasitic

Plant infections by plant-parasitic nematodes (PPNs) continue to be one of the major limitations in agricultural systems. Root-knot nematodes (RKNs), belonging to the genus Meloidogyne, are one of the most important groups of PPNs worldwide. Their wide host range combined with ubiquitous presence, continues to provide challenges for their control and breeding for resistance. Although resistance to RKNs has been identified, incorporation of these resistances into crops and durability of the resistance remains challenging. In addition, progress in cloning of RKN resistance genes has been dismal. Recent identification of pattern-triggered immunity in roots against nematodes, an ascaroside as a nematode-associated molecular pattern (NAMP) and the discovery of a NAMP plant receptor, provide tools and opportunities to develop durable host resistance against nematodes including RKNs.

scholarly journals TLR2 and TLR4 agonists stimulate unique repertoires of host resistance genes in murine macrophages: interferon-β-dependent signaling in TLR4-mediated responses

2003 ◽  
Vol 9 (3) ◽  
pp. 169-175 ◽  
Author(s):  
Vladimir Toshchakov ◽  
Bryan W. Jones ◽  
Arnd Lentschat ◽  
Aristobolo Silva ◽  
Pin-Yu Perera ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Host Resistance ◽  
Interferon Β ◽  
Murine Macrophages

scholarly journals New Pathotype Nomenclature for Better Characterisation the Virulence and Diversity of Blumeria graminis f.sp. avenae Populations

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1852
Author(s):  
Sylwia Okoń ◽  
Magdalena Cieplak ◽  
Adam Kuzdraliński ◽  
Tomasz Ociepa
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Host Resistance ◽  
Powdery Mildew Resistance ◽  
Blumeria Graminis ◽  
Sources Of Resistance ◽  
Mildew Resistance ◽  
Differential Set ◽  
Letter Code ◽  
First Time

Fungal cereal pathogens, including Blumeria graminis f.sp. avenae, have the ability to adapt to specific conditions, which in turn leads to overcoming host resistance. An important aspect is the standardized way of characterizing the races and pathotypes of the pathogen. In the presented work, for the first time it was proposed to use a unified letter code that allows describing the pathotypes of B. graminis f.sp. avenae. The set of 14 oat genotypes were used as a differential set. This set included genotypes having so far described powdery mildew resistance genes Pm1–Pm11, and two genotypes (A. sterilis and A. strigosa) with effective sources of resistance to Bga. Based on the analysis of 160 Bga isolates collected in 2016–2019 from 4 locations in Poland, the most numerous was the TBBB pathotype, represented by 30% of the tested isolates. It was present in all analyzed populations. Subsequently, 8.1% and 6.3% of the isolates represented the TBCB and RBBB pathotypes, respectively.

Sign in / Sign up

Export Citation Format

Share Document