scholarly journals Molecular and Morphological Evidence for Interspecific Hybridization Between Cronartium ribicola and C. comandrae on Pinus flexilis in Southwestern Alberta

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1552-1552 ◽  
Author(s):  
D. L. Joly ◽  
D. W. Langor ◽  
R. C. Hamelin

In May 2003, a survey was conducted in southwestern Alberta, east of the Rocky Mountains, to determine the extent of the spread and genetic diversity of white pine blister rust, which is caused by Cronartium ribicola J.C. Fisch. Aeciospores were sampled from white pine blister rust cankers in three infected limber pine (Pinus flexilis James) stands separated from one another by 100 to 215 km. DNA genotypes were determined for 12 codominant PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) loci representing genes derived from an EST library. At each site sampled, some aecia displayed DNA genotypes that were heterozygous at all loci and possessed novel alleles (GenBank Accession Nos. DQ009533-DQ009611). At Waterton Lakes, Kananaskis County, and Porcupine Hills, 29%, 11%, and 3% of sampled aecia and 38%, 33%, and 10% of sampled trees, respectively, possessed these unusual profiles. In May 2004, similar genetic profiles were found at two of these sites, Waterton Lakes and Kananaskis County, at 17 and 25% of sampled aecia (25% of sampled trees). In each of these aecia, genotyping and sequence analysis revealed this pattern was due to the presence of one C. ribicola and one C. comandrae Peck. allele at each of the 12 loci. Scanning electron microscopy (SEM) revealed aeciospore morphology that was intermediate between C. ribicola and C. comandrae. Aeciospores were longer (16 to 20 × 25 to 40 μm) than the expected range for C. ribicola (18 to 20 × 22 to 31 μm) (3). They were also fusiform, obovoid or short-to-long ellipsoid, but not pyriform-acuminate as in C. comandrae, and without a true conspicuous smooth spot as in C. ribicola. This provides evidence for interspecific hybridization between C. ribicola and C. comandrae, the causal agent of comandra blister rust. We hypothesize that the presence of nearby C. comandrae-infected lodgepole pine (P. contorta Dougl.) could have led to spermatization of C. ribicola receptive hyphae by C. comandrae pycniospores, resulting in the formation of hybrid aecia. An important question is whether these hybrids have a different host range that could potentially extend its geographic range in areas where the telial host, Ribes spp. L., is not abundant. The hybrid rust Melampsora × columbiana Newcombe was shown to exhibit virulence against certain hybrid poplar clones that had previously been reported as resistant against both parental rusts (M. medusae Thuem. and M. occidentalis Jacks) and abundant pathogenic variation has been observed (2). Furthermore, the ability to colonize unexpected hosts could provide fitness advantages over parental species, as was observed in Phytophthora spp. pathogenic on alder (1). Host range and virulence assays should be conducted to assess the potential impact of this hybrid. References: (1) C. M. Brasier et al. Proc. Natl. Acad. Sci. USA 96:5878, 1999. (2) G. Newcombe et al. Phytopathology 91:981, 2001. (3) W. G. Ziller. The Tree Rusts of Western Canada. Can. For Serv. No. 1329. Pacific Forestry Center, Victoria, BC, 1974.

1996 ◽  
Vol 72 (6) ◽  
pp. 637-638 ◽  
Author(s):  
Jean A. Bérubé

White pine seedlings were treated with triadimefon two weeks prior to natural inoculation with Cronartium ribicola and were observed for two growth seasons. During the second growth season in the greenhouse the incidence of blister rust symptoms was 70.8% for the untreated controls, whereas only 3.8% of the treated seedlings showed symptoms of blister rust. Triadimefon offers effective protection against white pine blister rust infection and would enable the production of bare root seedlings in areas prone to blister rust infection.


PLoS ONE ◽  
2016 ◽  
Vol 11 (5) ◽  
pp. e0154267 ◽  
Author(s):  
Jun-Jun Liu ◽  
Danelle Chan ◽  
Yu Xiang ◽  
Holly Williams ◽  
Xiao-Rui Li ◽  
...  

BMC Genomics ◽  
2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Jun-Jun Liu ◽  
Anna W. Schoettle ◽  
Richard A. Sniezko ◽  
Rona N. Sturrock ◽  
Arezoo Zamany ◽  
...  

2013 ◽  
Vol 43 (10) ◽  
pp. 919-928 ◽  
Author(s):  
Cyndi M. Smith ◽  
David W. Langor ◽  
Colin Myrholm ◽  
Jim Weber ◽  
Cameron Gillies ◽  
...  

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.


2000 ◽  
Vol 10 (3) ◽  
pp. 567-569 ◽  
Author(s):  
Stanislaw Pluta ◽  
Agata Broniarek-Niemiec

Field resistance to white pine blister rust (WPBR) (Cronartium ribicola J. C. Fischer) was investigated on 53 black currant (Ribes nigrum L.) genotypes (cultivars and breeding selections) in 1998 and 1999. Uredia did not form on the black currant `Titania' and 17 advanced selections during field evaluations made at the Experimental Orchard at Dabrowice, near Skierniewice, Poland.


Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 595-595 ◽  
Author(s):  
D. W. Johnson ◽  
W. R. Jacobi

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.


2016 ◽  
Vol 46 (9) ◽  
pp. 1173-1178 ◽  
Author(s):  
Richard A. Sniezko ◽  
Robert Danchok ◽  
Douglas P. Savin ◽  
Jun-Jun Liu ◽  
Angelia Kegley

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.


2007 ◽  
Vol 85 (3) ◽  
pp. 299-306 ◽  
Author(s):  
Bryce A. Richardson ◽  
Paul J. Zambino ◽  
Ned B. Klopfenstein ◽  
Geral I. McDonald ◽  
Lori M. Carris

The white-pine blister rust fungus, Cronartium ribicola Fisch. in Rabenh., continues to spread in North America, utilizing various aecial (primary) and telial (alternate) hosts, some of which have only recently been discovered. This introduced pathogen has been characterized as having low genetic diversity in North America, yet it has demonstrated a capacity to invade diverse environments. The recent discovery of this rust fungus on the telial host Pedicularis racemosa Dougl. ex Benth., raises questions of whether this host association represents a recent acquisition by C. ribicola or a long-standing host association that was overlooked. Here we explore two questions: (i) is host specialization detectable at a local scale and (ii) is the capacity to infect Pedicularis racemosa local or widespread? Genetic analysis of C. ribicola isolates from different aecial and telial hosts provided no evidence for genetic differentiation and showed similar levels of expected heterozygosity within a geographic population. An inoculation test showed that diverse C. ribicola sources from across North America had the capacity to infect Pedicularis racemosa. These results support a hypothesis that ability to infect Pedicularis racemosa is common in C. ribicola from North America. Utilization of Pedicularis racemosa by C. ribicola may be dependent on the co-occurrence of this host, inoculum, and favorable environments.


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