Risk of white pine blister rust to limber pine in Colorado and Wyoming, USA

Limber pine (Pinus flexilis E. James) is under threat from white pine blister rust (WPBR), mountain pine beetle, drought, and fire suppression across its range in western North America. In 2003–2004, we established 85 plots to assess the mortality and incidence of WPBR on limber pine, and remeasured them in 2009. Infection was evident in 74% of the plots in 2003–2004 and 88% of the plots in 2009. The proportion of dead trees increased from 32% in 2003–2004 to 35% in 2009. The percentage of live trees infected increased from 33% in 2003–2004 to 43% in 2009. Mean live limber pine basal area in 2009 ranged from 0.03 to 77.8 m2/ha per plot. Twenty (24%) of the plots had no seedlings in the first measurement, but only 15% in the second measurement. Seedling infection was low (8% in 2003–2004 and 4% in 2009). In 12 plots that were measured three times, mortality increased from 30% of all trees in 1996 to 50% in 2003, then decreased to 46% in 2009. Infection decreased from 73% of live trees in 1996 to 46% in 2003, then increased to 66% in 2009. High mortality and infection levels suggest that the long-term persistence of many limber pine populations in the southern part of the study area are in jeopardy, and continued monitoring is needed to assist with management decisions.

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First Report of White Pine Blister Rust in Colorado

Plant Disease ◽

10.1094/pdis.2000.84.5.595d ◽

2000 ◽

Vol 84 (5) ◽

pp. 595-595 ◽

Cited By ~ 18

Author(s):

D. W. Johnson ◽

W. R. Jacobi

Keyword(s):

White Pine Blister Rust ◽

White Pine ◽

Pinus Flexilis ◽

Limber Pine ◽

Blister Rust ◽

Continental Divide ◽

Northern Colorado ◽

Fort Collins ◽

Park Road ◽

Ribes Spp

In June 1999, a survey was conducted north and west of Redfeather Lakes, CO (≈64 km northwest of Fort Collins) to determine the extent of white pine blister rust, caused by Cronartium ribicola. To date the disease has not been reported in Colorado on any of the known hosts. The survey was initiated after the disease was reported on limber pine, Pinus flexilis, in 1998. A total of 65 sections were traveled by driving passable roads within three townships in Larimer County in northern Colorado. Infected limber pines were observed in nine sections. Incidence of infected trees ranged from 3 to 50% of trees sampled. A minimum of 10 trees was sampled at each location. Where trees were more abundant, 40 trees were sampled. The highest incidence of blister rust was observed near the Colorado and Wyoming state line along Cherokee Park Road. Both main stem and branch cankers were observed. Cankers appeared to be 3 to 5 years old. Mortality of entire trees was not observed. Ribes spp. were observed in the vicinity of infected limber pines. However, no infection was noted on these alternate rust hosts. Infected trees were observed 18 km south of the Colorado and Wyoming state line. The southward spread of the disease into northern Colorado from infection sites in Wyoming appears to have proceeded slowly since reports of the disease in southern Wyoming during the 1970s (1). Blister rust has the potential to spread throughout the range of white pines in Colorado, which includes scattered populations of both limber and bristlecone pines, P. aristata, located along the Continental Divide from Wyoming to the Colorado and New Mexico state line. References: (1) D. B. Brown. Plant Dis. Rep. 62:905, 1978.

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

Canadian Journal of Forest Research ◽

10.1139/cjfr-2016-0128 ◽

2016 ◽

Vol 46 (9) ◽

pp. 1173-1178 ◽

Cited By ~ 6

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.

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White Pine Blister Rust Resistance in Limber Pine: Evidence for a Major Gene

Phytopathology ◽

10.1094/phyto-04-13-0092-r ◽

2014 ◽

Vol 104 (2) ◽

pp. 163-173 ◽

Cited By ~ 25

Author(s):

A. W. Schoettle ◽

R. A. Sniezko ◽

A. Kegley ◽

K. S. Burns

Keyword(s):

Major Gene ◽

Management Strategies ◽

Genetic Resistance ◽

Stress Factors ◽

R Gene ◽

White Pine Blister Rust ◽

White Pine ◽

Individual Tree ◽

Limber Pine ◽

Blister Rust

Limber pine (Pinus flexilis) is being threatened by the lethal disease white pine blister rust caused by the non-native pathogen Cronartium ribicola. The types and frequencies of genetic resistance to the rust will likely determine the potential success of restoration or proactive measures. These first extensive inoculation trials using individual tree seed collections from >100 limber pine trees confirm that genetic segregation of a stem symptom-free trait to blister rust is consistent with inheritance by a single dominant resistance (R) gene, and the resistance allele appears to be distinct from the R allele in western white pine. Following previous conventions, we are naming the R gene for limber pine “Cr4.” The frequency of the Cr4 allele across healthy and recently invaded populations in the Southern Rocky Mountains was unexpectedly high (5.0%, ranging from 0 to 13.9%). Cr4 is in equilibrium, suggesting that it is not a product of a recent mutation and may have other adaptive significance within the species, possibly related to other abiotic or biotic stress factors. The identification of Cr4 in native populations of limber pine early in the invasion progress in this region provides useful information for predicting near-term impacts and structuring long-term management strategies.

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Limber Pine Regeneration and White Pine Blister Rust in the Central and Southern Rocky Mountains

Forest Science ◽

10.5849/forsci.16-052 ◽

2017 ◽

Vol 63 (2) ◽

pp. 151-164 ◽

Cited By ~ 4

Author(s):

Christy M. Cleaver ◽

William R. Jacobi ◽

Kelly S. Burns ◽

Robert E. Means

Keyword(s):

Rocky Mountains ◽

White Pine Blister Rust ◽

White Pine ◽

Southern Rocky Mountains ◽

Limber Pine ◽

Blister Rust ◽

Pine Regeneration

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First Report of White Pine Blister Rust on Rocky Mountain Bristlecone Pine

Plant Disease ◽

10.1094/pdis.2004.88.3.311a ◽

2004 ◽

Vol 88 (3) ◽

pp. 311-311 ◽

Cited By ~ 23

Author(s):

J. T. Blodgett ◽

K. F. Sullivan

Keyword(s):

Great Basin ◽

Sand Dunes ◽

Rocky Mountain ◽

White Pine Blister Rust ◽

White Pine ◽

First Report ◽

Limber Pine ◽

Blister Rust ◽

Bristlecone Pine ◽

Pinus Aristata

White pine blister rust caused by Cronartium ribicola was introduced into North America in the early 20th century and is spreading throughout the range of five-needle pines. In northern Colorado, this pathogen was first observed in 1998 on limber pine (Pinus flexilis) (1). It has not been reported on Rocky Mountain or Great Basin bristlecone pine (Pinus aristata and P. longaeva, respectively) in nature. However, Rocky Mountain bristlecone pine is susceptible to the disease when artificially inoculated (2). In October 2003, a Rocky Mountain bristlecone pine was found infected with C. ribicola in the Great Sand Dunes National Monument, Alamosa County, Colorado. Seven branch cankers were observed on the tree. Cankers ranged in length from 15 to 41 cm and were estimated to be approximately 5 to 7 years old. Distinct C. ribicola branch symptoms were observed, including flagging, spindle-shaped swellings, and 6 mm long aecial scars. A branch was deposited at the Colorado State Herbarium. Microscopic examination of spores within remnant aecial blisters revealed aeciospores characteristic of C. ribicola (yellow-orange, ellipsoid, verrucose, and 19 × 25 μm). Cankers were only observed on one bristlecone pine. However, most limber pines in the area were infected with C. ribicola, including a limber pine less than 1 m from the infected bristlecone pine. To our knowledge, this is the first report that shows Rocky Mountain bristlecone pine can become infected naturally, and the pathogen is further south in Colorado on limber pine than previously reported. These observations suggest the need for a more complete investigation of this disease on bristlecone pines. References: (1) D. W. Johnson and W. R. Jacobi. Plant Dis. 84:595, 2000. (2) B. R. Stephan, Allg. Forst Z. 28:695, 1985.

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A method for estimating white pine blister rust canker age on limber pine in the central Rocky Mountains

Forest Pathology ◽

10.1111/j.1439-0329.2008.00575.x ◽

2009 ◽

Vol 39 (3) ◽

pp. 177-191 ◽

Cited By ~ 7

Author(s):

Holly S. J. Kearns ◽

William R. Jacobi ◽

Brian W. Geils

Keyword(s):

Rocky Mountains ◽

White Pine Blister Rust ◽

White Pine ◽

Limber Pine ◽

Blister Rust ◽

Central Rocky Mountains

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Comparative association mapping reveals conservation of major gene resistance to white pine blister rust in southwestern white pine (Pinus strobiformis) and limber pine (P. flexilis)

Phytopathology ◽

10.1094/phyto-09-21-0382-r ◽

2021 ◽

Author(s):

Jun-Jun Liu ◽

Anna W Schoettle ◽

Richard Sniezko ◽

Kristen M Waring ◽

Holly Williams ◽

...

Keyword(s):

Molecular Mechanisms ◽

Quantitative Resistance ◽

Major Gene ◽

Snp Markers ◽

Genomic Diversity ◽

White Pine Blister Rust ◽

White Pine ◽

Limber Pine ◽

Blister Rust ◽

Major Gene Resistance

All native North American white pines are highly susceptible to white pine blister rust (WPBR) caused by Cronartium ribicola. Understanding genomic diversity and molecular mechanisms underlying genetic resistance to WPBR remains one of the great challenges in improvement of white pines. To compare major gene resistance (MGR) present in two species, southwestern white pine (Pinus strobiformis) Cr3 and limber pine (P. flexilis) Cr4, we performed association analyses of Cr3-controlled resistant traits using SNP assays designed with Cr4-linked polymorphic genes. We found that ~ 70% of P. flexilis SNPs were transferable to P. strobiformis. Furthermore, several Cr4-linked SNPs were significantly associated with the Cr3-controlled traits in P. strobiformis families. The most significantly associated SNP (M326511_1126R) almost co-localized with Cr4 on the Pinus consensus linkage group 8 (LG-8), suggesting that Cr3 and Cr4 might be the same R locus, or have localizations very close to each other in the syntenic region of the P. strobiformis and P. flexilis genomes. M326511_1126R was identified as a non-synonymous SNP, causing amino acid change (Val376Ile) in a putative pectin acetylesterase (PAE), with coding sequences identical between the two species. Moreover, top Cr3-associated SNPs were further developed as TaqMan genotyping assays, suggesting their usefulness as marker-assisted selection (MAS) tools to distinguish genotypes between quantitative resistance (QR) and MGR. This work demonstrates the successful transferability of SNP markers between two closely related white pine species in the hybrid zone, and the possibility for deployment of MAS tools to facilitate long-term WPBR management in P. strobiformis breeding and conservation.

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The distribution and incidence of white pine blister rust in central and southeastern Wyoming and northern Colorado

Canadian Journal of Forest Research ◽

10.1139/x06-231 ◽

2007 ◽

Vol 37 (2) ◽

pp. 462-472 ◽

Cited By ~ 25

Author(s):

Holly S.J. Kearns ◽

William R. Jacobi

Keyword(s):

Current Level ◽

Slope Position ◽

White Pine Blister Rust ◽

White Pine ◽

Pinus Flexilis ◽

Limber Pine ◽

Blister Rust ◽

The Past ◽

Northern Colorado ◽

Diameter Classes

A survey of limber pine ( Pinus flexilis James) to determine the geographic distribution, incidence, and severity of white pine blister rust (WPBR) throughout 13 study areas in central and southeastern Wyoming and northern Colorado was conducted from 2002 to 2004. The majority (81.1%) of the 18 719 surveyed limber pines >1.37 m tall were classified as healthy, 13.5% were declining or dying from various causes, and 5.4% were dead. WPBR was present on 278 (55%) of the 504 survey plots. Incidence of the disease ranged from 0% to 100% and averaged 15.5% over all the plots and 28.0% on the infested plots. Likelihood of infection by WPBR was significantly greater for limber pines in larger diameter classes. Incidence was negatively correlated with elevation and positively correlated with geographic position, with more northerly and easterly plots having higher incidences of WPBR. Incidence varied by slope position and did not vary by aspect, slope configuration, or degree of canopy closure. The current level of infestation in central and southeastern Wyoming and northern Colorado has been attained within the past two to four decades. With time, the pathogen may spread to currently uninfested white pine populations and intensify throughout its current distribution impacting valuable ecosystems.

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