Later events in suppression of Fusarium root rot of red pine seedlings by the ectomycorrhizal fungus Paxillus involutus

1991 ◽  
Vol 69 (6) ◽  
pp. 1372-1383 ◽  
Author(s):  
M. L. Farquhar ◽  
R. L. Peterson
Keyword(s):  
Pinus Resinosa ◽  
Ectomycorrhizal Fungus ◽  
Red Pine ◽  
Disease Suppression ◽  
Host Cells ◽  
Paxillus Involutus ◽  
Free System ◽  
Primary Roots ◽  
Pine Seedlings ◽  
Rooting Medium

Colonization of primary roots of red pine (Pinus resinosa Ait.) seedlings by two isolates of the fungal pathogen Fusarium oxysporum Schlecht. emend Snyd. & Hans. f.sp. pini in a sterile, soil-free system and a nonsterile rooting medium was suppressed for 2 months if the roots were exposed to the ectomycorrhizal fungus Paxillus involutus (Batsch.) Fr. for 1 week before being inoculated with the pathogen. Roots of protected seedlings harboured only a few hyphae of the pathogen. These were either vacuolated or filled with slightly electron-dense substances and did not penetrate host cells. In contrast, roots of seedlings not inoculated by P. involutus were extensively colonized by F. oxysporum, and host tissue vacuolation and disorganization occurred. Papillae, consisting of either small protuberances or elongate projections, were infrequently formed in response to infection. Chlamydospores of F. oxysporum that formed in the sterile system had numerous lipid deposits and amorphous thick walls but few mitochondria and little endoplasmic reticulum. Key words: biological control, ectomycorrhiza, Fusarium, Pinus resinosa, disease suppression.

Disease suppression by the ectomycorrhizal fungus Paxillus involutus: contribution of oxalic acid

1989 ◽  
Vol 67 (9) ◽  
pp. 2726-2730 ◽  
Author(s):  
Luc C. Duchesne ◽  
Brian E. Ellis ◽  
R. L. Peterson
Keyword(s):  
Oxalic Acid ◽  
Root Rot ◽  
High Performance ◽  
Root Exudate ◽  
Gel Filtration ◽  
Pinus Resinosa ◽  
Fold Increase ◽  
Ectomycorrhizal Fungus ◽  
Disease Suppression ◽  
Paxillus Involutus

Seedlings of Pinus resinosa Ait. grown in test tubes were inoculated with the ectomycorrhizal fungus Paxillus involutus Fr. Oxalic acid was identified as one of the ethanol-soluble fungistatic and (or) fungitoxic components of the rhizosphere after fractionation by high performance liquid chromatography, paper chromatography, and gel filtration. Simultaneous inoculation of P. resinosa seedlings with authentic oxalic acid and a spore suspension of Fusarium oxysporum f.sp. pini protected the seedlings against Fusarium root rot and decreased the sporulation of F. oxysporum in the rhizosphere when compared with controls lacking oxalic acid. Quantitation of oxalic acid showed a five fold increase in production by Pax. involutus in tubes containing P. resinosa seedlings when compared with tubes lacking seedlings. The synthesis of oxalic acid by Pax. involutus is, therefore, stimulated by P. resinosa root exudate.

Effects of Hebeloma arenosa on growth and survival of container-grown red pine seedlings (Pinus resinosa)

1991 ◽  
Vol 21 (10) ◽  
pp. 1459-1465 ◽  
Author(s):  
J. S. MacFall ◽  
S. A. Slack
Keyword(s):  
Seedling Survival ◽  
Pinus Resinosa ◽  
Ectomycorrhizal Fungus ◽  
Commercial Production ◽  
Red Pine ◽  
Shoot Height ◽  
Growth And Survival ◽  
Fungal Inoculum ◽  
Pine Seedlings ◽  
Production Conditions

The ability of the ectomycorrhizal fungus Hebelomaarenosa Burdsall, MacFall & Albers to enhance growth and survival of container-grown red pine seedlings (Pinusresinosa Ait.) was investigated. Shoot height of H. arenosa inoculated seedlings was 28% greater than noninoculated seedlings when grown without fertilizer applications. Eight-week-old seedlings transplanted into a Ball mix (a mixture of peat, bark, and perlite) containing up to a 1:64 dilution of fungal inoculum had significantly greater root dry weights and root/shoot ratios than noninoculated seedlings when grown for an additional 14 weeks. Under experimental greenhouse conditions, root and shoot dry weights of container-grown red pine seedlings that had been directly seeded into Ball mix containing up to a 1:256 dilution of fungal inoculum were significantly greater than weights measured for noninoculated seedlings. Root and shoot dry weights of container-grown seedlings seeded directly into a 1:5 dilution of H. arenosa inoculum and Ball mix and then grown under commercial production conditions were greater than comparable weights of noninoculated seedlings. Hebelomaarenosa inoculation significantly increased seedling survival following outplanting, but did not increase seedling growth. Hebelomaarenosa did not colonize roots growing from the root plug into the surrounding soil.

Early effects of the ectomycorrhizal fungus Paxillus involutus on the root rot organism Fusarium associated with Pinus resinosa

1990 ◽  
Vol 68 (7) ◽  
pp. 1589-1596 ◽  
Author(s):  
M. L. Farquhar ◽  
R. L. Peterson
Keyword(s):  
Pinus Resinosa ◽  
Ectomycorrhizal Fungus ◽  
Test Tube ◽  
Disease Suppression ◽  
Wall Material ◽  
Paxillus Involutus ◽  
Calcofluor White ◽  
Cytoplasmic Inclusions ◽  
Early Effects ◽  
Root Tissues

Infection of Pinus resinosa Ait. seedlings in a sterile test tube culture system by Fusarium oxysporum f.sp. pini Schlecht. emend. Snyd. & Hans., which was determined microscopically by the presence of the fungus within root tissues, was significantly reduced within the first 6 days of infection after prior inoculation with the ectomycorrhizal fungus Paxillus involutus (Batsch) Fr. Hyphae and conidia of the pathogen were swollen and filled with osmiophilic material when P. involutus was also present in the rhizosphere of P. resinosa seedlings. Germination of F. oxysporum conidia was suppressed when they were placed in holes in P. involutus cultures on modified Melin Norkrans medium in Petri plates but was restored with removal of conidia from plates. Suppressed, ungerminated conidia had thick cell walls and large cytoplasmic inclusions. Staining using Calcofluor White M2R New revealed changes in the binding properties of septal wall material. Key words: Paxillus, Fusarium, ectomycorrhiza, disease suppression, anatomy.

Interaction between the ectomycorrhizal fungus Paxillus involutus and Pinus resinosa induces resistance to Fusarium oxysporum

1988 ◽  
Vol 66 (3) ◽  
pp. 558-562 ◽  
Author(s):  
Luc C. Duchesne ◽  
R. L. Peterson ◽  
Brian E. Ellis
Keyword(s):  
Fusarium Oxysporum ◽  
Seedling Survival ◽  
Pathogenic Fungus ◽  
Pinus Resinosa ◽  
Ectomycorrhizal Fungus ◽  
Antibiotic Activity ◽  
Disease Suppression ◽  
Paxillus Involutus ◽  
Subsequent Infection ◽  
Fivefold Increase

Inoculation of Pinus resinosa Ait. seedlings with the ectomycorrhizal fungus Paxillus involutus Fr. resulted in a 47% increase in resistance to subsequent infection by the root pathogenic fungus Fusarium oxysporum f.sp. pini as compared with control seedlings. This increase in seedling survival was associated with a sixfold decrease in the sporulation of F. oxysporum in the rhizosphere of seedlings inoculated with Pax. involutus when compared with the rhizosphere of control seedlings. Extraction and bioassay of the seedling rhizosphere and seedling tissues indicated that inoculation with Pax. involutus led to a fivefold increase in antibiotic activity in the rhizosphere of the seedlings treated with Pax. involutus. Most or all of the fungitoxicity was localized in the rhizosphere. Disease suppression by Pax. involutus in P. resinosa is, therefore, associated with an increase of fungitoxic chemicals in the rhizosphere of seedlings.

Effects of Hebeloma arenosa and phosphorus fertility on root acid phosphatase activity of red pine (Pinus resinosa) seedlings

1991 ◽  
Vol 69 (2) ◽  
pp. 380-383 ◽  
Author(s):  
Janet MacFall ◽  
Steven A. Slack ◽  
Jaya Iyer
Keyword(s):  
Enzyme Activity ◽  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Fungal Growth ◽  
Pinus Resinosa ◽  
Ectomycorrhizal Fungus ◽  
Red Pine ◽  
Nitrophenyl Phosphate

The ectomycorrhizal fungus Hebeloma arenosa Burdsall, MacFall & Albers was assayed for surface-accessible acid phosphatase activity in vitro on roots of red pine (Pinus resinosa Ait.) seedlings. Hebeloma arenosa was grown in defined liquid media containing 0, 17, 34, 68, or 136 mg/L phosphorus for 4 weeks. When assayed for acid phosphatase activity with p-nitrophenyl phosphate, 7.3 μmol of orthophosphate were released per gram dry weight of fungal tissue. There was no effect of added P on enzyme activity, excluding the treatment with no added P in which there was negligible fungal growth. Red pine seedlings were grown in Sparta loamy fine sand amended with 0, 17, 34, 68, or 136 mg/kg P as superphosphate, with and without H. arenosa inoculum. Mycorrhizal roots had greater enzyme activity than nonmycorrhizal roots of seedlings grown in similarly P-amended soil. This was determined by the following three assays: orthophosphate release from two salts of myoinosital hexaphosphate (Na and KMg) and from p-nitrophenyl phosphate. It is suggested that greater acid phosphatase activity by roots mycorrhizal with H. arenosa is one mechanism for improved P nutrition through the formation of a pool of P released from sources unavailable for direct intake.

scholarly journals Resistance of Pinus banksiana to the European race of Gremmeniella abietina

2005 ◽  
Vol 81 (2) ◽  
pp. 49-55 ◽  
Author(s):  
G. Laflamme ◽  
R. Blais
Keyword(s):  
Distinctive Feature ◽  
Pinus Banksiana ◽  
Pinus Resinosa ◽  
Jack Pine ◽  
Red Pine ◽  
The North ◽  
Pine Seedlings ◽  
Pine Trees ◽  
European Race ◽  
Low Incidence

In the early 1980s, more than 90% of mortality caused by Gremmeniella abietina, European race, was recorded in red pine (Pinus resinosa) plantations 200 km northwest of Montreal, Quebec, Canada. Surrounding jack pines (Pinus banksiana) did not appear to be affected. Consequently, foresters began to plant the affected areas with jack pine seedlings. In 1988, plots of 100 jack pines were established in three of the four selected plantations. As reference, red pine seedlings were planted in 1989 under similar conditions in the fourth plantation. Observations were carried out annually from 1989 to 1992. Mortality of red pine seedlings reached 70% in 1992 while all jack pines on the three experimental sites were free of the disease except for a tip blight, a distinctive feature allowing race identification in the field. The North American race symptoms were present at a very low incidence, but began to increase on site I in 1992. More than 10 years after planting, the jack pine trees still show resistance to the European race of G. abietina while all the red pines died.

Effects of Hebeloma arenosa and phosphorus fertility on growth of red pine (Pinus resinosa) seedlings

1991 ◽  
Vol 69 (2) ◽  
pp. 372-379 ◽  
Author(s):  
Janet MacFall ◽  
Steven A. Slack ◽  
Jaya Iyer
Keyword(s):  
Growth Promotion ◽  
Pinus Resinosa ◽  
Fine Sand ◽  
Red Pine ◽  
Fertility Treatment ◽  
Fungal Colonization ◽  
Growth Enhancement ◽  
Tissue Concentrations ◽  
Unamended Soil ◽  
Pine Seedlings

Red pine seedlings (Pinus resinosa Ait.) were grown in a pasteurized Sparta loamy fine sand (8–12 ppm P) amended with five levels (0, 17, 34, 68, or 136 mg/kg P) of added superphosphate. Trees for each fertility treatment were grown in containers for 19 weeks with and without addition of Hebeloma arenosa inoculum to soil. In P-unamended soil, all inoculated trees formed abundant mycorrhizae and had 12 times the root and 8 times the shoot dry weights of nonmycorrhizal trees. Degree of fungal colonization and growth enhancement decreased with increased P additions to soil. In soil with the highest level of added P, mycorrhizal colonization and growth promotion effects were not observed. Seedling tissue concentrations of P and K were increased with fungal colonization. Iron was preferentially accumulated in the roots of mycorrhizal trees, with reduced translocation to shoots. In P-unamended soil, nonmycorrhizal plants had greater concentrations of Cu, B, Na, and Co compared with either mycorrhizal seedlings or plants grown in P-amended soil. Key words: ectomycorrhizae, roots, plant nutrition.

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