Genetic Models of Host–pathogen Gene Interaction Based on Inoculation of Loblolly Pine Seedlings with the Fusiform Rust Fungus

New Forests ◽  
2006 ◽  
Vol 31 (2) ◽  
pp. 245-252 ◽  
Author(s):  
Hua Li ◽  
Henry Amerson ◽  
Bailian Li
Keyword(s):  
Loblolly Pine ◽  
Rust Fungus ◽  
Gene Interaction ◽  
Genetic Models ◽  
Fusiform Rust ◽  
Pine Seedlings ◽  
Host Pathogen

scholarly journals Genetic Interaction of the Fusiform Rust Fungus with Resistance Gene Fr1 in Loblolly Pine

2005 ◽  
Vol 95 (4) ◽  
pp. 376-380 ◽  
Author(s):  
Thomas L. Kubisiak ◽  
Henry V. Amerson ◽  
C. Dana Nelson
Keyword(s):  
Loblolly Pine ◽  
Genetic Interaction ◽  
Rust Fungus ◽  
Gene Interaction ◽  
Multiple Infections ◽  
Fusiform Rust ◽  
Competition Study ◽  
Physical Mixing ◽  
Inoculation Procedure ◽  
Avr Genes

We propose a method for defining DNA markers linked to Cronartium quercuum f. sp. fusiforme avirulence (Avr) genes. However, before this method can be successfully employed, a spore competition study was needed to determine the genetic composition of single pycnial drops and multiple drops on single galls when using the standard inoculation procedure, whether virulent (avr1) basidiospores ever predispose some resistant (Fr1/fr1) trees to infection by avirulent (Avr1) basidiospores, and whether avr1 and Avr1 basidiospores equally infect susceptible (fr1/fr1) trees. Results of this study suggest that multiple infections within a single gall are common using the concentrated basidiospore system, resulting on average in >4 infection events per tree. Due to multiple infections within a single gall, an individual pycnial drop cannot be assumed to consist of spores from only a single haploid pycnium. Roughly 57% of the drops harvested were found to consist of more than one haploid genotype, most likely due to the physical mixing of spores from genetically different pycnia. Most importantly, although multiple infections do occur in the formation of a single gall, there is no evidence to suggest that the genetics of the proposed gene-for-gene interaction are compromised. Only avr1 basidiospores were observed to cause infection on Fr1/fr1 trees, whereas both avr1 and Avr1 basidiospores were observed to cause infection on fr1/fr1 trees, albeit not at equal frequencies.

Indirect selection and clonal propagation of loblolly pine seedlings enhance resistance to fusiform rust

1989 ◽  
Vol 19 (4) ◽  
pp. 534-537 ◽  
Author(s):  
G. S. Foster ◽  
R. L. Anderson
Keyword(s):  
Loblolly Pine ◽  
Rust Resistance ◽  
Clonal Propagation ◽  
Indirect Selection ◽  
Artificial Inoculation ◽  
Fusiform Rust ◽  
Rooted Cutting ◽  
Pine Seedlings ◽  
Susceptible Control ◽  
High Degree

A population of loblolly pine (Pinustaeda L.) seedlings without fusiform rust (Cronartiumquercuum (Berk.) Miyabe ex Shirai f.sp. fusiforme) galls was developed by controlled-cross matings of parent trees with known rust resistance, and subsequent screening of the seedling offspring through artificial inoculation. The seedlings without rust galls then entered a vegetative propagation system using rooted cuttings. A second round of rust testing by artificial inoculation, using a random sample of 20 clones from the program, revealed a high degree of rust resistance (4% galled) compared with that of seedlings from either a resistant control seedlot (50% galled) or a susceptible control seedlot (81% galled). This apparently high degree of rust resistance may be due to genetic effects, rooted cutting morphology, or both.

scholarly journals Eight-Year Field Performance of Pine Seedlings after Mycorrhizae Were Triadimefon-Inhibited in the Nursery

1996 ◽  
Vol 20 (1) ◽  
pp. 42-44
Author(s):  
W. A. Carey ◽  
W. D. Kelley
Keyword(s):  
Loblolly Pine ◽  
Field Performance ◽  
Fusiform Rust ◽  
Pine Seedlings ◽  
Mycorrhizal Development

Abstract Loblolly pine seedlings were not sprayed with a fungicide or were sprayed with triadimefon (Bayleton®) at 6 oz ai/ac or with twice or four times that rate to differentially suppress mycorrhizal development. Seedlings were planted at three sites and evaluated in the eighth year after outplanting. Fusiform rust incidence and tree heights and diameters differed significantly between nursery sources and among outplanting sites, but not between triadimefon treatments. Survival did not differ between sites, nursery sources or triadimefon treatments. South. J. Appl. For. 20(1):42-44.

Influence of Fertilization and Ectomycorrhizae on Loblolly Pine Growth and Susceptibility to Fusiform Rust

1983 ◽  
Vol 7 (2) ◽  
pp. 101-103 ◽  
Author(s):  
H. R. Powers ◽  
S. J. Rowan
Keyword(s):  
Loblolly Pine ◽  
Cultural Practices ◽  
Mycorrhizal Fungus ◽  
Height Growth ◽  
Pisolithus Tinctorius ◽  
Fusiform Rust ◽  
Infected Tree ◽  
Pine Seedlings ◽  
Susceptible Control ◽  
Rust Severity

Abstract The application of fertilizer and the mycorrhizal fungus, Pisolithus tinctorius, did not increase the height growth of loblolly pine seedlings during their first four years of growth. Fertilization, however, did increase the overall number of fusiform rust galls per infected tree. This increase was highly significant on the susceptible control seedlings, but was not significant on resistant Livingston Parish seedlings. This indicates that cultural practices such as fertilization can be applied to rust-resistant seedlings, such as the Livingston Parish seed source, without significantly increasing rust severity.

Cyproconazole for Control of Fusiform Rust on Loblolly Pine Seedlings

1994 ◽  
Vol 18 (3) ◽  
pp. 101-104 ◽  
Author(s):  
W. A. Carey ◽  
W. D. Kelley
Keyword(s):  
Seedling Growth ◽  
Loblolly Pine ◽  
Seed Treatment ◽  
Foliar Spray ◽  
Seed Treatments ◽  
Fusiform Rust ◽  
Foliar Sprays ◽  
Pine Seedlings ◽  
Mycorrhizal Development

Abstract The efficacy of cyproconazole seed treatments and foliar sprays for control of fusiform rust on loblolly pine seedlings was evaluated in greenhouse and nursery trials. At the nursery, the percentage of untreated seedlings that were galled at lifting was high (54%). No seedlings receiving cyproconazole at the lowest dosage foliar spray (4 sprays at 123.25 g ai/ha/application ) without the seed treatment, and only 0.1% of seedlings receiving only the seed treatment (1.25 g ai/kg seed), were galled Laboratory inoculations indicated that seed treatments with cyproconazole at 1.25 and 2.5 g ai/kg seed were effective for at least 20 and 30 days, respectively, and that foliar sprays of 185.0 or 246.5 g ai/ha were effective for 14 but not 21 days. Eleven months after sowing, mycorrhizal development in the nursery was similar among seedlings receiving approximately equal dosages of either cyproconazole or triadimefon. Seedling growth was not significantly different between control seedlings and those receiving the various dosages of cyproconazole. South J. Appl. For. 18(3): 101-104.

Predicting Severity of Fusiform Rust in Young Loblolly and Slash Pine Stands in Florida, Georgia, and the Carolinas

1986 ◽  
Vol 10 (1) ◽  
pp. 38-41 ◽  
Author(s):  
Robert L. Anderson ◽  
Noel D. Cost ◽  
Joe P. McClure ◽  
George Ryan
Keyword(s):  
Loblolly Pine ◽  
Geographic Location ◽  
Slash Pine ◽  
Fusiform Rust ◽  
Rust Infection ◽  
Know How ◽  
Resource Managers ◽  
Pine Seedlings ◽  
Prevention Techniques ◽  
Pine Stands

Abstract Resource managers need to know how severe fusiform rust is likely to be before they plant southern pine seedlings in an area. The system described allows the manager to estimate the probability of having different amounts of rust infection in newly established stands. By selecting the geographic location of a stand, the species, and the type of regeneration, the manager can assess these probabilities. The system allows the user to compare the probabilities for slash and loblolly pine and to select prevention techniques, such as the use of resistant planting stock.

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