Early symptom development in lodgepole pine seedlings infected with Endocronartium harknessii

1990 ◽  
Vol 68 (2) ◽  
pp. 270-277 ◽  
Author(s):  
Eric A. Allen ◽  
P. V. Blenis ◽  
Y. Hiratsuka
Keyword(s):  
Pinus Contorta ◽  
Rust Fungus ◽  
Infected Tissue ◽  
Cortical Cells ◽  
Subsequent Formation ◽  
Early Symptom ◽  
Pine Seedlings ◽  
Endocronartium Harknessii ◽  
Periderm Formation ◽  
Lignin Deposition

Six-week-old Pinus contorta seedlings were inoculated with spores of the western gall rust fungus Endocronartium harknessii. Of 660 seedlings inoculated, 174 showed early symptoms and were sampled for histological observation in the 7 weeks following inoculation. Pigmentation of epidermal cells was the first externally visible response to infection, generally occurring 14–28 days after inoculation. Developing symptoms were extremely variable, ranging from little or no visible response to severe necrosis. The appearance of external symptoms was largely due to changes occurring in underlying infected cortical cells such as the production of phenolic compounds, necrophylactic periderm, or necrotic tissue. Intercellular lignin deposition was observed in infected tissue and was thought to be associated with necrophylactic periderm formation. Suppression of normal exophylactic periderm development was evident in virtually all infected tissue zones. Infection of the vascular cambium occurred as early as 21 days after inoculation and resulted in the subsequent formation of distorted xylem tracheids typical of gall tissue.

Histological evidence of resistance to Endocronartium harknessii in Pinus contorta var. latifolia

1990 ◽  
Vol 68 (8) ◽  
pp. 1728-1737 ◽  
Author(s):  
E. A. Allen ◽  
P. V. Blenis ◽  
Y. Hiratsuka
Keyword(s):  
Pinus Contorta ◽  
Secondary Xylem ◽  
Rust Fungus ◽  
Cortical Lesions ◽  
Gall Formation ◽  
Cortical Cells ◽  
Endocronartium Harknessii ◽  
Infected Cells ◽  
Initial Resistance ◽  
Resistance To Infection

Resistance to the western gall rust fungus, Endocronartium harknessii, was observed in 3-, 10-, 20-, and 33-month-old greenhouse-grown seedlings of lodgepole pine (Pinus contorta var. latifolia). Three sites of resistance were identified: epidermal, cortical, and cambial. In cases of epidermal resistance, penetration of the epidermis occurred, but infection was prevented by an apparent hypersensitive response. Cortical resistance occurred where infected cells in the cortex were successfully isolated by necrophylactic periderm and the infected tissue was exfoliated with the rhytidome. In cambial resistance, infections progressed to the vascular cambium where infected cells and cambial initials were inactivated. This resulted in abnormal secondary xylem development, characterized by a zone of pathological tissue extending from the pith to the epidermis. In a number of infected seedlings, cambial function was restored and infected lesions were overgrown. Live mycelium was often maintained in cortical lesions and in some cases reinvaded healthy cortical cells. These latent-type infections resulted in the initiation of gall formation up to 1 year after initial resistance to infection occurred. Key words: tree improvement, western gall rust, pine stem rust.

Early symptoms and resistance of lodgepole pine seedlings inoculated with western gall rust

1992 ◽  
Vol 70 (6) ◽  
pp. 1274-1278 ◽  
Author(s):  
H. O. Kojwang ◽  
B. J. van der Kamp
Keyword(s):  
Pinus Contorta ◽  
Rust Fungus ◽  
Good Prediction ◽  
Gall Formation ◽  
Inoculum Concentration ◽  
Early Symptoms ◽  
Pine Seedlings ◽  
Endocronartium Harknessii ◽  
One Year ◽  
Two Stages

One-year-old seedlings in 10 open-pollinated Pinus contorta families were inoculated with spores of the rust fungus Endocronartium harknessii at two stages of seedling maturity and two levels of inoculum concentration. The early symptoms (general red stain, red flecks, red streaks) that appeared on the seedlings were recorded 2, 4, and 8 weeks after inoculation, while the number of galls was recorded 1 year after inoculation. The frequency of general red stain and red flecks varied significantly among families. Resistance of families as percent of seedlings producing galls also varied significantly. The frequency of early symptoms was only poorly correlated with family resistance. Also, the occurrence of early symptoms on individual seedlings did not give a good prediction of gall formation on them. These results suggest that early symptoms cannot accurately identify resistant families or individuals. Key words: Endocronartium harknessii, Pinus contorta, symptoms, resistance.

Susceptibility of Pinus contorta - Pinus banksiana complex to Endocronartium harknessii: host-pathogen interactions

1999 ◽  
Vol 77 (7) ◽  
pp. 1035-1043 ◽  
Author(s):  
Rong-Cai Yang ◽  
Zhihong Ye ◽  
Yasu Hiratsuka
Keyword(s):  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Rust Fungus ◽  
Jack Pine ◽  
Natural Hybridization ◽  
Host Group ◽  
Group Interactions ◽  
Endocronartium Harknessii ◽  
Rust Susceptibility

Lodgepole (Pinus contorta Dougl. ex Lound.) and jack (Pinus banksiana Lamb.) pines occur sympatrically and hybridize in central and northwestern Alberta, providing opportunities for studying unique ecological and evolutionary interactions. We conducted a greenhouse inoculation experiment to investigate interactions between 40 populations of lodgepole and jack pines and their putative hybrids across this hybrid zone and two sources of the western gall rust fungus, Endocronartium harknessii (J.P. Moore) Y. Hiratsuka, one from lodgepole pine and the other from jack pine. Rust susceptibility and height were assessed when the seedlings were 6 months and 1 year old. Lodgepole pine and the hybrids were significantly more susceptible to the rust infection than jack pine. Jack pine grew significantly faster than the hybrids and lodgepole pine. In addition, the seedlings infected with spores from lodgepole pine grew significantly slower than those with spores from jack pine. While the overall rust scores indicated that spores from lodgepole pine was more virulent to the hosts than those from jack pine, both spore sources were better adapted to their own host species, causing significant spore source × host group interactions. However, such host specificity in the western gall rust is far from stabilized (equilibrium) because of continued gene exchanges among the two parental species and their hybrids.Key words: Pinus contorta - Pinus banksiana complex, western gall rust, natural hybridization, coevolutionary genetics.

Random amplified polymorphic DNA variability among geographic isolates of western gall rust fungus in Canada

2001 ◽  
Vol 31 (8) ◽  
pp. 1304-1311 ◽  
Author(s):  
Changxi Li ◽  
Francis C Yeh ◽  
Yasu Hiratsuka
Keyword(s):  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Random Amplified Polymorphic Dna ◽  
Rust Fungus ◽  
Jack Pine ◽  
Fungal Isolates ◽  
Rapd Pattern ◽  
Endocronartium Harknessii ◽  
East West

Geographic variability among western gall rust (WGR) fungus (Endocronartium harknessii (J.P. Moore) Y. Hiratsuka) was studied by random amplified polymorphic DNA (RAPD). Samples were taken from lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) host at four locations in British Columbia and Alberta and from jack pine (Pinus banksiana Lamb.) host at nine locations in Alberta, Saskatchewan, Manitoba, and Ontario. Of 90 random oligonucleotide primers screened, 9 were chosen for analysis. These nine primers consistently amplified 41 sharp and reproducible RAPDs (fragments) of the WGR fungal isolates over several independent runs. Eighteen of the 41 RAPDs were polymorphic (showing the presence of both marker and null phenotypes), of which 15 could discriminate WGR isolates of lodgepole pine hosts from jack pine ones. Of these 15 RAPDs, five were unique to isolates of lodgepole and five to jack pine. The remaining five RAPDs were significantly heterogeneous in the RAPD frequency between WGR isolates of the two host origins. The RAPD pattern of WGR isolates from lodgepole pine was uniform. However, isolates from jack pine differed significantly in the frequency of four RAPDs among locations, with an east-west trend of decreasing similarity in RAPD. Analysis of molecular variance apportioned 76.3, 14.4, and 9.3% of the total RAPD variability to differences among hosts, to differences among locations within hosts, and to differences within locations, respectively. The large differentiation between WGR fungal isolates sampled in lodgepole pine and jack pine hosts might suggest that selective pressure for host specificity in sampled populations was strong.

Histopathology of Albugo tragopogonis on stems and petioles of sunflower

1999 ◽  
Vol 77 (1) ◽  
pp. 175-178
Author(s):  
H Krüger ◽  
A Viljoen ◽  
P S Van Wyk
Keyword(s):  
Cell Division ◽  
Key Words ◽  
Helianthus Annuus ◽  
Systemic Infection ◽  
Infected Tissue ◽  
Tissue Integrity ◽  
Callose Formation ◽  
Stem Lesions ◽  
Lignin Deposition

Stem lesions in sunflower caused by Albugo tragopogonis (Pers.) S.F. Gray developed individually from primary infections and did not result from a systemic infection. Cell division and callose formation were not observed, but weak lignin deposition occurred in infected tissues. Hyphae occurred intercellularly in stems in the cortex, cambium, vascular rays, and pith. In petioles parenchymatous tissue was heavily colonized in contrast to lightly colonized collenchymatous hypodermis. The middle lamellae of cells in infected tissue were dissolved, and cells degenerated and eventually collapsed. Stem infections lead to deterioration of tissue integrity, weakening of stems, and finally to lodging of stems (breaking over).Key words: Albugo tragopogonis, Helianthus annuus, histopathology, stem lodging.

Soil nitrogen and lodgepole pine seedling responses to five years of legume cover

1998 ◽  
Vol 74 (4) ◽  
pp. 578-582 ◽  
Author(s):  
J. M. Kranabetter ◽  
R. Trowbridge
Keyword(s):  
Soil Nitrogen ◽  
Forest Floor ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Seeding Density ◽  
Total N ◽  
Pine Seedlings ◽  
Key Words Nitrogen Fixation ◽  
Multiple Species ◽  
Key Words Nitrogen

Legumes were tested for their ability to increase soil N content and improve growth of lodgepole pine (Pinus contorta Dougl. ex Loud.) seedlings in west-central British Columbia. A trial with alsike clover at varying densities were tested at one site, while three legume species (alsike clover, birdsfoot trefoil, and white clover) were tested on a second site. After five years of legume cover, mineralizable N mass of the forest floor were 0.5 to 4.5 times those of controls. Total N of the forest floor more than doubled in the seeding density study compared with controls, but was insignificant in the multiple species study. Despite observed increases in soil nitrogen, lodgepole pine growth was not enhanced by the legume treatments. Factors such as N immobilization, root distribution, low S levels, and competition for B may have limited the response of lodgepole pine seedlings to additions of biologically fixed-N. Key words: nitrogen-fixation, legumes, lodgepole pine, soil nitrogen

Lodgepole pine provenances differ in chemical defense capacities against foliage and stem diseases

2010 ◽  
Vol 40 (12) ◽  
pp. 2333-2344 ◽  
Author(s):  
Christopher M. Wallis ◽  
Richard W. Reich ◽  
Kathy J. Lewis ◽  
Dezene P.W. Huber
Keyword(s):  
Secondary Metabolites ◽  
Pinus Contorta ◽  
Dominant Species ◽  
Lodgepole Pine ◽  
Quantitative Resistance ◽  
Foliar Diseases ◽  
Seed Sources ◽  
Endocronartium Harknessii ◽  
Foliar Concentrations ◽  
Foliar Pathogens

Maximization of lodgepole pine ( Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson) growth in a future climate with increased pest activity requires an understanding of the natural variability of quantitative resistance to disease. Foliar and bark secondary metabolites from different lodgepole pine provenances (populations) were quantified and correlated with severity of foliar diseases caused by Lophodermella spp. ( Lophodermella concolor (Dearn.) Darker or Lophodermella montivaga Petre.) or Elytroderma deformans (Wier) Darker and bark diseases caused by Elytroderma or Endocronartium harknessii (J.P. Moore) Y. Hiratsuka. Greater foliar concentrations of lignin, tannins, and some phenolics were associated with increased resistance to single or multiple foliar pathogens. Bark secondary metabolites levels were generally unassociated with resistance to bark diseases. Provenances appearing to originate in ecosystems where lodgepole pine are not the dominant species generally were more susceptible to foliar diseases and had less foliar defense-associated compounds than trees from areas where pines were the dominant species, yet clear trends proved to be elusive. Regardless, pine provenances with greater foliar levels of identified defense-associated compounds should be preferred seed sources for replanting forests in areas in which foliar disease is expected to be increasingly prevalent.

Symptoms in slash pine seedlings following inoculation with the cone rust fungus Cronartium strobilinum

2001 ◽  
Vol 31 (6) ◽  
pp. 345-352 ◽  
Author(s):  
A. N. Shukla ◽  
R. A. Schmidt ◽  
T. Miller
Keyword(s):  
Rust Fungus ◽  
Slash Pine ◽  
Pine Seedlings

Biotrophic associations between lodgepole pine seedlings and postfire ascomycetes (Pezizales) in monoxenic culture

1986 ◽  
Vol 64 (11) ◽  
pp. 2719-2725 ◽  
Author(s):  
Keith N. Egger ◽  
J. W. Paden
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Root Surface ◽  
Mycorrhizal Symbiosis ◽  
Vascular Cylinder ◽  
Limited Capacity ◽  
Monoxenic Culture ◽  
Pine Seedlings ◽  
Sphaerosporella Brunnea ◽  
Pathogenic Infection

Twenty-two species of postfire ascomycetes belonging to the order Pezizales were screened for biotrophic interactions with roots of lodgepole pine (Pinus contorta Dougl.). Biotrophic associations ranged from pathogenicity to mycorrhizal symbiosis, but most species tested did not show any affinity for roots. Pyropyxis rubra (Peck) Egger and Rhizina undulata Fr. were aggressive pathogens that infected the vascular cylinder and killed the seedlings. Tricharina praecox (Karst.) Dennis var. intermedia Egger, Yang & Korf also had some ability to infect the vascular cylinder, but usually did not kill the seedlings. Geopyxis carbonaria (A. & S.) Sacc. and Trichophaea hemisphaerioides (Mont.) Graddon invaded the cortex, forming complex intracellular structures, but did not penetrate the vascular cylinder. They may form mutualistic associations under certain conditions. The only confirmed mutualistic species was Sphaerosporella brunnea (A. & S.) Svrcek & Kubicka, which formed ectendomycorrhizae. Anthracobia maurilabra (Cooke) Boud. and A. tristis (Bomm., Rouss. & Sacc.) Boud. appear to be primarily root-surface inhabitants with limited capacity to infect cortical tissues through breaks in the epidermis. Gyromitra infula (Schaef.) Quél. penetrated the epidermis but was unable to overcome host defences against pathogenic infection.

Predicting survival of lodgepole pine stands infected with western gall rust

2006 ◽  
Vol 36 (4) ◽  
pp. 878-885 ◽  
Author(s):  
J M Wolken ◽  
P V Blenis ◽  
I Duncan
Keyword(s):  
Pinus Contorta ◽  
Management Strategy ◽  
Tree Mortality ◽  
Lodgepole Pine ◽  
Main Stem ◽  
Iteratively Reweighted Least Squares ◽  
Risk Of Mortality ◽  
Endocronartium Harknessii ◽  
Stem Gall ◽  
Pine Stands

The probability of lodgepole pine (Pinus contorta Dougl. ex Loud.) having main-stem galls caused by western gall rust, Endocronartium harknessii (J.P. Moore) Y. Hiratsuka, surviving to rotation is unknown. To evaluate survival, 400 galled trees with at least one stem gall and 400 trees without stem galls were measured in 1992 in two precommercially thinned stands approximately 20 years old. The survival of trees was assessed in 2003. Nonlinear regression using iteratively reweighted least squares was employed to estimate the survival of galled trees as a function of the proportion of the main stem encircled by galls. Galls encircling >79% and >91% of the stem in the two stands increased the risk of mortality relative to non-galled trees, with the risk increasing steeply with percent gall encirclement; smaller stem galls did not cause tree mortality. The 11-year pattern of survival of galled trees was similar for infections that occurred on the main stem and those that had reached the stem from a nearby branch infection. Based on an earlier model of gall expansion, 38%–43% of stem-galled trees would be expected to survive until age 80. Scribing of stem galls to prevent their expansion does not appear to be a feasible management strategy.

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