Race ofCronartium ribicolaVirulent to Major Gene Resistance in Sugar Pine

Plant Disease ◽  
1981 ◽  
Vol 65 (7) ◽  
pp. 604 ◽  
Author(s):  
B. B. Kinloch
Keyword(s):  
Major Gene ◽  
Major Gene Resistance ◽  
Sugar Pine

scholarly journals Evidence of Cytoplasmic Inheritance of Virulence in Cronartium ribicola to Major Gene Resistance in Sugar Pine

1999 ◽  
Vol 89 (3) ◽  
pp. 192-196 ◽  
Author(s):  
Bohun B. Kinloch ◽  
Gayle E. Dupper
Keyword(s):  
Infection Type ◽  
Major Gene ◽  
Nuclear Gene ◽  
Cronartium Ribicola ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Mendelian Segregation ◽  
Blister Rust ◽  
Major Gene Resistance ◽  
Sugar Pine

Tests for Mendelian segregation of virulence and avirulence in Cronartium ribicola, causal agent of white pine blister rust, to a major gene (R) for resistance in sugar pine were made using haploid basidiospore progenies from single diploid telia as inoculum on resistant genotypes. The telia were sampled from a small deme in the Siskyou Mountains of northern California, where a few mature sugar pines known to be Rr genotypes had become infected after withstanding the chronic blister rust epidemic for several decades and where intermediate frequencies of virulence in the ambient basidiospore population were subsequently measured. Infection type on inoculated seedlings with R was qualitative: all progenies of 81 single telia tested over 3 different years were either virulent (compatible) or avirulent (inducing hypersensitive necrosis), never a mixture of both reactions. The complete absence of heterozygotes in the telia population is strong evidence that virulence is not controlled by a nuclear gene. The data are consistent with earlier tests showing that basidiospore inoculum derived from aeciospores isolated from infected Rr trees produced mostly (>90%) virulent reactions on R— seedlings. The evidence indicates that transmission of virulence is uniparental via the cytoplasm of aeciospores. Exchange of spermatia between haploid thalli does not appear to be involved.

Restricted distribution of a virulent race of the white pine blister rust pathogen in the western United States

1987 ◽  
Vol 17 (5) ◽  
pp. 448-451 ◽  
Author(s):  
Bohun B. Kinloch Jr. ◽  
Gayle E. Dupper
Keyword(s):  
United States ◽  
Major Gene ◽  
Resistance Mechanisms ◽  
Western United States ◽  
White Pine Blister Rust ◽  
Blister Rust ◽  
Rate Of Spread ◽  
Major Gene Resistance ◽  
Sugar Pine ◽  
Resistant Genotypes

A race of Cronartiumribicola virulent to a major gene for resistance to blister rust in sugar pine appears to be limited to the site where first discovered on resistant genotypes in 1978. It was not detected in inocula surveyed extensively throughout a large part of the range of blister rust in the western United States and detected only rarely in inocula surrounding the discovery site. Nor was it found attacking resistant genotypes in other test plantings either nearby or remote from this site. Rate of spread of the virulent race from the discovery site was too slow to be measured during 6 years of observation. These results imply that major gene resistance may be usable for at least one rotation of improved planting stock, while other resistance mechanisms are being developed.

scholarly journals Influence of Host Resistance on the Genetic Structure of the White Pine Blister Rust Fungus in the Western United States

2008 ◽  
Vol 98 (4) ◽  
pp. 413-420 ◽  
Author(s):  
B. A. Richardson ◽  
N. B. Klopfenstein ◽  
P. J. Zambino ◽  
G. I. McDonald ◽  
B. W. Geils ◽  
...  
Keyword(s):  
United States ◽  
Genetic Structure ◽  
North America ◽  
Major Gene ◽  
Western United States ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Blister Rust ◽  
Major Gene Resistance ◽  
Sugar Pine

Cronartium ribicola, the causal agent of white pine blister rust, has been devastating to five-needled white pines in North America since its introduction nearly a century ago. However, dynamic and complex interactions occur among C. ribicola, five-needled white pines, and the environment. To examine potential evolutionary influences on genetic structure and diversity of C. ribicola in western United States, population genetic analyses of C. ribicola were conducted using amplified fragment length polymorphism (AFLP) molecular markers. The fungus was sampled at six sites. Collections for two of the six sites were from separate plantings of resistant-selected western white pine and sugar pine. Heterozygosity based on polymorphic loci among populations ranged from 0.28 to 0.40, with resistant-selected plantations at the extremes. Genetic differentiation was also highest between these two populations. Principal coordinates analysis and Bayesian assignment placed most isolates that are putative carriers of virulence to major-gene resistance into a discernable cluster, while other isolates showed no clustering by site or host species. These results indicate that C. ribicola in western North America is not genetically uniform, despite its presumed single site of introduction and relatively brief residence. Moreover, major-gene resistance appears to have imposed strong selection on the rust, resulting in reduced genetic diversity. In contrast, no evidence of selection was observed in C. ribicola from hosts that exhibit only multigenic resistance.

Cotyledon test for major gene resistance to white pine blister rust in sugar pine

1980 ◽  
Vol 58 (17) ◽  
pp. 1912-1914 ◽  
Author(s):  
Bohun B. Kinloch Jr. ◽  
Mardi Comstock
Keyword(s):  
Major Gene ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Blister Rust ◽  
Pine Seedlings ◽  
Major Gene Resistance ◽  
Sugar Pine ◽  
Time Required ◽  
Resistant Genotypes

Major gene resistance (hypersensitivity) to white pine blister rust can be detected on cotyledons of inoculated sugar pine seedlings shortly after germination. The cotyledon test reduces the time required for evaluating resistant genotypes from a few years to a few weeks.

scholarly journals Root Rot of Juniperus and Microbiota by Phytophthora lateralis in Oregon Horticultural Nurseries

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1500-1506
Author(s):  
Ebba K. Peterson ◽  
Franziska Rupp ◽  
Joyce Eberhart ◽  
Jennifer L. Parke
Keyword(s):  
Root Rot ◽  
Internal Transcribed Spacer ◽  
Major Gene ◽  
Resistance Breeding ◽  
Its2 Region ◽  
Phytophthora Spp ◽  
Major Gene Resistance ◽  
Phytophthora Lateralis ◽  
Chamaecyparis Lawsoniana ◽  
Port Orford Cedar

Widespread symptoms of root rot and mortality on Juniperus communis and Microbiota decussata were observed in two horticultural nurseries in Oregon, leading to the isolation of a Phytophthora sp. from diseased roots. Based on morphology and sequencing the internal transcribed spacer ITS1-5.8S-ITS2 region, isolates were identified as the invasive pathogen Phytophthora lateralis, causal agent of Port-Orford-cedar (POC; Chamaecyparis lawsoniana) root disease. Additional sequencing of the cytochrome c oxidase subunit 1 and 2 genes identified all isolates as belonging to the PNW lineage. Utilizing recovered isolates plus a POC-wildlands isolate and susceptible POC as controls, we completed Koch’s postulates on potted Juniperus and Microbiota plants. Nursery isolates were more aggressive than the forest isolate, which was used in the POC resistance breeding program. Increased aggressiveness was confirmed using a branch stem dip assay with four POC clones that differed in resistance, although no isolate completely overcame major-gene resistance. Isolates were sensitive to mefenoxam, a fungicide commonly used to suppress Phytophthora spp. growth in commercial nurseries. Although POC resistance is durable against these more aggressive nursery isolates, the expanded host range of P. lateralis challenges POC conservation through the continued movement of P. lateralis by the nursery industry.

scholarly journals Inhibition of Resistance Gene-Mediated Defense in Rice by Xanthomonas oryzae pv. oryzicola

2006 ◽  
Vol 19 (3) ◽  
pp. 240-249 ◽  
Author(s):  
Seiko Makino ◽  
Akiko Sugio ◽  
Frank White ◽  
Adam J. Bogdanove
Keyword(s):  
Bacterial Blight ◽  
Major Gene ◽  
Rice Cultivar ◽  
Hypersensitive Reaction ◽  
Xanthomonas Oryzae ◽  
R Gene ◽  
R Genes ◽  
Apparent Lack ◽  
Type Iii ◽  
Major Gene Resistance

Xanthomonas oryzae pv. oryzae and the closely related X. oryzae pv. oryzicola cause bacterial blight and bacterial leaf streak of rice, respectively. Although many rice resistance (R) genes and some corresponding avirulence (avr) genes have been characterized for bacterial blight, no endogenous avr/R gene interactions have been identified for leaf streak. Genes avrXa7 and avrXa10 from X. oryzae pv. oryzae failed to elicit the plant defense-associated hypersensitive reaction (HR) and failed to prevent development of leaf streak in rice cultivars with the corresponding R genes after introduction into X. oryzae pv. oryzicola despite the ability of this pathovar to deliver an AvrXa10:Cya fusion protein into rice cells. Furthermore, coinoculation of X. oryzae pv. oryzicola inhibited the HR of rice cultivar IRBB10 to X. oryzae pv. oryzae carrying avrXa10. Inhibition was quantitative and dependent on the type III secretion system of X. oryzae pv. oryzicola. The results suggest that one or more X. oryzae pv. oryzicola type III effectors interfere with avr/R gene-mediated recognition or signaling and subsequent defense response in the host. Inhibition of R gene-mediated defense by X. oryzae pv. oryzicola may explain, in part, the apparent lack of major gene resistance to leaf streak.

scholarly journals Genetic resistance to white pine blister rust in limber pine (Pinus flexilis): major gene resistance in a northern population

2016 ◽  
Vol 46 (9) ◽  
pp. 1173-1178 ◽  
Author(s):  
Richard A. Sniezko ◽  
Robert Danchok ◽  
Douglas P. Savin ◽  
Jun-Jun Liu ◽  
Angelia Kegley
Keyword(s):  
Major Gene ◽  
Genetic Resistance ◽  
The United States ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Pinus Flexilis ◽  
Limber Pine ◽  
Blister Rust ◽  
Major Gene Resistance ◽  
The Status

Limber pine, Pinus flexilis E. James, a wide-ranging tree species in western North America, is highly susceptible to white pine blister rust (WPBR), caused by the non-native fungal pathogen Cronartium ribicola J.C. Fisch. The Canadian populations in particular have been heavily impacted, and in 2014, limber pine was designated endangered in Canada by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Little is known about genetic resistance to WPBR in limber pine, but major gene resistance (MGR) has been characterized in some populations in the United States. This study examines resistance in seedling families from 13 parent trees from British Columbia, Alberta, and Oregon, representing the northern- and northwestern-most populations. Most families were susceptible, with 100% of the seedlings cankered, but one family from Alberta segregated 1:1 for cankered and canker free. This is the first report of (a) MGR in Canada of any of the four species of five-needle pines native to Canada and (b) any resistance in limber pine in Canadian populations and is the northernmost known incidence of putative R-gene resistance in a natural stand of any five-needle pine species. Many of the Canadian selections were from stands with high incidence of WPBR infection, and their high susceptibility in this trial suggests that further infection and mortality is likely in the Canadian populations.

scholarly journals Pyramiding Quantitative Resistance with a Major Resistance Gene in Apple: From Ephemeral to Enduring Effectiveness in Controlling Scab

Plant Disease ◽  
2018 ◽  
Vol 102 (11) ◽  
pp. 2220-2223 ◽  
Author(s):  
Pauline Lasserre-Zuber ◽  
Valérie Caffier ◽  
René Stievenard ◽  
Arnaud Lemarquand ◽  
Bruno Le Cam ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Plant Disease ◽  
Quantitative Resistance ◽  
Major Gene ◽  
Genetic Resistance ◽  
Control Plant ◽  
Resistance Factors ◽  
Major Gene Resistance ◽  
Major Resistance Gene ◽  
Over Time

Genetic resistance is a useful strategy to control plant disease, but its effectiveness may be reduced over time due to the emergence of pathogens able to circumvent the defenses of the plant. However, the pyramiding of different resistance factors in the same plant can improve the effectiveness and durability of the resistance. To investigate the potential for this approach in apple to control scab disease we surveyed scab incidence in two experimental orchards located at a distance of more than 300 km planted with apple genotypes carrying quantitative resistance and major gene resistance alone or in combination. Our results showed that the effectiveness of pyramiding in controlling scab was dependent on the site and could not be completely explained by the effectiveness level of the resistances alone.

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