scholarly journals A Single Gene Cluster Controls Incompatibility and Partial Resistance to Various Melampsora larici-populina Races in Hybrid Poplars

1998 ◽  
Vol 88 (2) ◽  
pp. 156-163 ◽  
Author(s):  
F. Lefèvre ◽  
M. C. Goué-Mourier ◽  
P. Faivre-Rampant ◽  
M. Villar
Keyword(s):  
Gene Cluster ◽  
Partial Resistance ◽  
Random Amplified Polymorphic Dna ◽  
Single Gene ◽  
Field Resistance ◽  
Clonal Variation ◽  
Multiple Alleles ◽  
Hybrid Poplars ◽  
Genetic Background Effect ◽  
Trait Locus

Complete cosegregation for race-specific incompatibility with three Melampsora larici-populina rust races was observed in five F1 hybrid progenies of Populus, with different patterns among the various progenies. A single gene cluster could explain these segregations: one locus with multiple alleles or two tightly linked loci controlling complete resistance to E1 and E3, and two tightly linked loci for E2. The random amplified polymorphic DNA marker OPM03/04_480 was linked to that cluster in all families (<1 cM). This marker accounted for more than 70% of the genetic variation for field resistance in each family (heritability ≈ 0.40). The same marker accounted for up to 64% of the clonal variation for growth in the nursery under natural inoculum pressure; the weak tolerance to rust of F1 interspecific hybrids was attributed to a genetic background effect. Partial resistance was split into epidemiological components (heritability ranged from 0.35 to 0.87). Genotypic correlations among resistance traits for the different races were high (0.73 to 0.90). However, correlations among different resistance components for a single race were not all significant. A major quantitative trait locus for all components of partial resistance to E2 was associated to the cluster controlling incompatibility to E1 and E3 and marked by OPM03/04_480 (R2from 48 to 68%).

Hazelnut Pollination

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 555d-555
Author(s):  
J.L. Olsen ◽  
S.A. Mehlenbacher ◽  
A.N. Azarenko
Keyword(s):  
Single Gene ◽  
Pistillate Flower ◽  
Temperature Dependent ◽  
Multiple Alleles ◽  
Anisogramma Anomala ◽  
Molecular Aspects ◽  
Management Recommendations ◽  
Pollen Shed ◽  
Resistant Genotypes ◽  
Pollination And Fertilization

Hazelnuts are wind-pollinated, monoecious, mostly dichogamous, and self-incompatible of the sporophytic type. About 90% of the cultivars studied are protandrous. Anthesis of the pistillate flower is temperature-dependent and occurs from December through February, with its peak in January. Stigmatic surfaces may remain receptive for up to 3 months. Four to 5 months separate pollination and fertilization of the ovule, which usually occurs between mid-May and the end of June in Oregon. A 10% pollinizer density has been the standard, with a recommended distance of <20 m between the main cultivar and the nearest pollinizer. Two or three different pollinizer varieties with different times of pollen shed are recommended. The Oregon hazelnut industry is presently combating the fungal disease, Eastern Filbert Blight, Anisogramma anomala. Part of the current management recommendations are to reduce the susceptible pollinizer varieties to a density of around 5%, and then gradually replace those left with immune or more-resistant genotypes. Recent research by S.A. Mehlenbacher refined methods of using fluorescense microscopy to quickly determine genotype compatibility. The self-incompatiblity is controlled by a single gene with multiple alleles. The biochemical, physiological, and molecular aspects of sporophytic self-incompatiblity are being research by A.N. Azarenko.

scholarly journals High-resolution analysis of cis -acting regulatory networks at the α-globin locus

2013 ◽  
Vol 368 (1620) ◽  
pp. 20120361 ◽  
Author(s):  
Jim R. Hughes ◽  
Karen M. Lower ◽  
Ian Dunham ◽  
Stephen Taylor ◽  
Marco De Gobbi ◽  
...  
Keyword(s):  
High Resolution ◽  
Gene Cluster ◽  
Regulatory Networks ◽  
Single Gene ◽  
Regulatory Elements ◽  
Circular Chromosome ◽  
Chromosome Conformation ◽  
Cis Acting ◽  
High Resolution Analysis ◽  
Resolution Analysis

We have combined the circular chromosome conformation capture protocol with high-throughput, genome-wide sequence analysis to characterize the cis -acting regulatory network at a single locus. In contrast to methods which identify large interacting regions (10–1000 kb), the 4C approach provides a comprehensive, high-resolution analysis of a specific locus with the aim of defining, in detail, the cis -regulatory elements controlling a single gene or gene cluster. Using the human α-globin locus as a model, we detected all known local and long-range interactions with this gene cluster. In addition, we identified two interactions with genes located 300 kb (NME4) and 625 kb (FAM173a) from the α-globin cluster.

Genetic dissection of partial resistance to race 6 of Venturia inaequalis in apple

Genome ◽  
2003 ◽  
Vol 46 (2) ◽  
pp. 224-234 ◽  
Author(s):  
C E Durel ◽  
L Parisi ◽  
F Laurens ◽  
W E Van de Weg ◽  
R Liebhard ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Malus Domestica ◽  
Quantitative Trait ◽  
Partial Resistance ◽  
Venturia Inaequalis ◽  
Genetic Dissection ◽  
Resistance Breakdown ◽  
Trait Locus ◽  
New Races ◽  
Genomic Regions

Scab, caused by the fungus Venturia inaequalis, is one of the most important diseases of apple (Malus × domestica). The major resistance gene, Vf, has been widely used in apple breeding programs, but two new races of the fungus (races 6 and 7) are able to overcome this gene. A mapped F1 progeny derived from a cross between the cultivars Prima and Fiesta has been inoculated with two monoconidial strains of race 6. These strains originated from sporulating leaves of 'Prima' and a descendant of 'Prima' that were grown in an orchard in northern Germany. 'Prima' carries the Vf resistance gene, whereas 'Fiesta' lacks Vf. A large variation in resistance and (or) susceptibility was observed among the individuals of the progeny. Several quantitative trait loci (QTLs) for resistance were identified that mapped on four genomic regions. One of them was located in the very close vicinity of the Vf resistance gene on linkage group LG-1 of the 'Prima' genetic map. This QTL is isolate specific because it was only detected with one of the two isolates. Two out of the three other genomic regions were identified with both isolates (LG-11 and LG-17). On LG-11, a QTL effect was detected in both parents. The genetic dissection of this QTL indicated a favourable intra-locus interaction between some parental alleles.Key words: Malus × domestica, partial resistance, Venturia inaequalis, resistance breakdown, quantitative trait locus.

scholarly journals Resistance to Downy Mildew in Lettuce ‘La Brillante’ is Conferred by Dm50 Gene and Multiple QTL

2015 ◽  
Vol 105 (9) ◽  
pp. 1220-1228 ◽  
Author(s):  
Ivan Simko ◽  
Oswaldo E. Ochoa ◽  
Mathieu A. Pel ◽  
Cayla Tsuchida ◽  
Carolina Font i Forcada ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Field Experiments ◽  
Field Resistance ◽  
Phenotypic Variance ◽  
Lactuca Sativa L ◽  
Trait Locus ◽  
Group 2 ◽  
High Level ◽  
Harvest Maturity ◽  
Multiple Field

Many cultivars of lettuce (Lactuca sativa L.) are susceptible to downy mildew, a nearly globally ubiquitous disease caused by Bremia lactucae. We previously determined that Batavia type cultivar ‘La Brillante’ has a high level of field resistance to the disease in California. Testing of a mapping population developed from a cross between ‘Salinas 88’ and La Brillante in multiple field and laboratory experiments revealed that at least five loci conferred resistance in La Brillante. The presence of a new dominant resistance gene (designated Dm50) that confers complete resistance to specific isolates was detected in laboratory tests of seedlings inoculated with multiple diverse isolates. Dm50 is located in the major resistance cluster on linkage group 2 that contains at least eight major, dominant Dm genes conferring resistance to downy mildew. However, this Dm gene is ineffective against the isolates of B. lactucae prevalent in the field in California and the Netherlands. A quantitative trait locus (QTL) located at the Dm50 chromosomal region (qDM2.2) was detected, though, when the amount of disease was evaluated a month before plants reached harvest maturity. Four additional QTL for resistance to B. lactucae were identified on linkage groups 4 (qDM4.1 and qDM4.2), 7 (qDM7.1), and 9 (qDM9.2). The largest effect was associated with qDM7.1 (up to 32.9% of the total phenotypic variance) that determined resistance in multiple field experiments. Markers identified in the present study will facilitate introduction of these resistance loci into commercial cultivars of lettuce.

scholarly journals The RPi-mcd1 Locus from Solanum microdontum Involved in Resistance to Phytophthora infestans, Causing a Delay in Infection, Maps on Potato Chromosome 4 in a Cluster of NBS-LRR Genes

2008 ◽  
Vol 21 (7) ◽  
pp. 909-918 ◽  
Author(s):  
M. Y. Adillah Tan ◽  
Ronald C. B. Hutten ◽  
Carolina Celis ◽  
Tae-Ho Park ◽  
Rients E. Niks ◽  
...  
Keyword(s):  
Late Blight ◽  
Late Blight Resistance ◽  
Field Resistance ◽  
R Gene ◽  
Chromosome 4 ◽  
Solanum Microdontum ◽  
Plant Maturity ◽  
Trait Locus ◽  
Plant Pathogen Interactions ◽  
Resistance Data

The distinction between field resistance and resistance based on resistance (R) genes has been proven valid for many plant–pathogen interactions. This distinction does not seem to be valid for the interaction between potato and late blight. In this study, a locus involved in late blight resistance, derived from Solanum microdontum, provides additional evidence for this lack of distinction. The resistance is associated with a hypersensitive response and results in a delay of infection of approximately 1 to 2 weeks. Both a quantitative as well as a qualitative genetic approach were used, based on data from a field assay. Quantitative trait locus (QTL) analysis identified a QTL on chromosome 4 after correction of the resistance data for plant maturity. A qualitative genetic analysis resulted in the positioning of this locus on the short arm of chromosome 4 in between amplified fragment length polymorphism marker pCTmACG_310 and cleaved amplified polymorphic sequence markers TG339 and T0703. This position coincides with a conserved Phytophthora R gene cluster which includes R2, R2-like, RPi-blb3, and RPi-abpt. This implies that RPi-mcd1 is the fifth R gene of this nucleotide-binding site leucine-rich repeat cluster. The implications of our results on R-gene-based and field resistance are discussed.

scholarly journals Biosynthesis of 2′-Chloropentostatin and 2′-Amino-2′-Deoxyadenosine Highlights a Single Gene Cluster Responsible for Two Independent Pathways in Actinomadura sp. Strain ATCC 39365

2017 ◽  
Vol 83 (10) ◽  
Author(s):  
Yaojie Gao ◽  
Gudan Xu ◽  
Pan Wu ◽  
Jin Liu ◽  
You-sheng Cai ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Single Gene ◽  
Combinatorial Biosynthesis ◽  
Pathway Engineering ◽  
Enzymatic Reactions ◽  
Strain Atcc ◽  
Nudix Hydrolase ◽  
Nucleoside Antibiotics ◽  
Chemical Structures ◽  
Hydrolysis Of

ABSTRACT 2′-Chloropentostatin (2′-Cl PTN, 2′-chloro-2′-deoxycoformycin) and 2′-amino-2′-deoxyadenosine (2′-amino dA) are two adenosine-derived nucleoside antibiotics coproduced by Actinomadura sp. strain ATCC 39365. 2′-Cl PTN is a potent adenosine deaminase (ADA) inhibitor featuring an intriguing 1,3-diazepine ring, as well as a chlorination at C-2′ of ribose, and 2′-amino dA is an adenosine analog showing bioactivity against RNA-type virus infection. However, the biosynthetic logic of them has remained poorly understood. Here, we report the identification of a single gene cluster (ada) essential for the biosynthesis of 2′-Cl PTN and 2′-amino dA. Further systematic genetic investigations suggest that 2′-Cl PTN and 2′-amino dA are biosynthesized by independent pathways. Moreover, we provide evidence that a predicted cation/H+ antiporter, AdaE, is involved in the chlorination step during 2′-Cl PTN biosynthesis. Notably, we demonstrate that 2′-amino dA biosynthesis is initiated by a Nudix hydrolase, AdaJ, catalyzing the hydrolysis of ATP. Finally, we reveal that the host ADA (designated ADA1), capable of converting adenosine/2′-amino dA to inosine/2′-amino dI, is not very sensitive to the powerful ADA inhibitor pentostatin. These findings provide a basis for the further rational pathway engineering of 2′-Cl PTN and 2′-amino dA production. IMPORTANCE 2′-Cl PTN/PTN and 2′-amino dA have captivated the great interests of scientists, owing to their unusual chemical structures and remarkable bioactivities. However, the precise logic for their biosynthesis has been elusive for decades. Actually, the identification and elucidation of their biosynthetic pathways not only enrich the biochemical repertoire of novel enzymatic reactions but may also lay solid foundations for the pathway engineering and combinatorial biosynthesis of this family of purine nucleoside antibiotics to generate novel hybrid analogs with improved features.

scholarly journals Genetic Analysis of Phytophthora Root Rot Race-specific Resistance in Chile Pepper

2008 ◽  
Vol 133 (6) ◽  
pp. 825-829 ◽  
Author(s):  
Ariadna Monroy-Barbosa ◽  
Paul W. Bosland
Keyword(s):  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Single Gene ◽  
Phytophthora Capsici ◽  
Segregation Ratio ◽  
Descent Method ◽  
Chile Pepper ◽  
Phytophthora Root Rot ◽  
Multiple Alleles ◽  
Seven Generations

Phytophthora capsici Leon., causal agent of phytophthora root rot, is one of the most devastating pathogens attacking chile pepper (Capsicum annuum L.) plants. Many studies have tried to better understand phytophthora resistance, but the genetic behavior is not completely understood. To determine if phytophthora root rot resistance in chile pepper is controlled by multiple alleles at a few loci, or multiple genes at different loci, five recombinant inbred lines (RILs) were evaluated. The resistant accession, Criollo de Morelos-334, and the susceptible cultivar, Early Jalapeno, were hybridized to develop multiple RILs. After seven generations of selfing using the single seed descent method, four RILs were selected based on their phenotypic response to inoculation by five P. capsici isolates. The RILs were hybridized to each other to obtain F1 and F2 populations. The F2 populations were inoculated with single and a pair of races of P. capsici. When the F2 populations were inoculated with a single race, ratios of three resistant:one susceptible were obtained in the majority of the populations, indicating the action of an independent single gene. When the F2 populations were inoculated with a combination of two races, segregation ratios of 15 resistant:one susceptible were observed in two populations out of the four populations. The presence of susceptible individuals in all of the F2 population indicates that the resistant genes for the different P. capsici races are located at different loci. However, the rejection of the segregation ratio in one of the F2 population under a single race inoculation and in two of the F2 populations challenged with a combination of two races suggest a linkage phenomenon between some of the R genes. None of the RILs evaluated in this study displayed allelism for phytophthora root rot resistance.

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