High elevation limber pine stands (Pinus flexilis), prevalent in the Rocky Mountain region, face a new challenge that threatens their long-term viability in the region. White pine blister rust is an invasive fungi that came to North America from Asia in the late twentieth century. The fungus has dual obligate hosts in the limber pine and the gooseberry, and thus requires both species in order to spread and thrive.
The life cycle of the white pine blister rust fungus is complex; it requires the limber pine and the gooseberry plant as obligate hosts, and moves back and forth between the two according to the season.
Generally, the spores of the fungus grow through the stomata on the needles or through a wound in the bark of the tree. The fungus then grows into the branch, causing swelling. After a year or more, the fungus erupts through the bark in blister-like sacs that break, releasing the fungus’ spores to nearby hosts. The fungus may take up to a couple of years to kill an entire tree.
White pine blister rust destroys young limber pine trees by blocking nutrient and water transport to the distal portion of branches, causing branch kill. If the fungus reaches the trunk, it can cause topkill, often leading to the death of the tree.
There are environmental, socio-economic, ecological, scientific, and aesthetic impacts of the loss of the highly valued high elevation limber pine and while the fungus is unlikely to wipe out entire limber pine stands it still impacts species distribution, population dynamics, and ecosystem functioning. Pine mortality caused by rust is predicted to convert currently forested slopes into treeless areas, affecting erosion and watersheds. Scientists also predict that mortality caused by the white pine blister rust will overall increase homogeneity in state forests and reduce biodiversity.
Scientists have been investigating the types and frequencies of white pine blister rust resistant limber pines in hopes of developing a preemptive conservation plan to enhance the limber pine populations overall resistance to the pathogen. In a recent article in the journal Phytopathology, forest researchers have identified a dominant gene which they have named Cr4. This gene was found to be present in anywhere from 0.5% to 14% of recently infested limber pine populations.
There is immense ecological value to the identification of resistance genes early on in the process of fungus infestation. The discovery enables the Forest Service to optimize cost effective management strategies.
Scientists Define Resistance Allele in Rocky Mountain Limber Pine
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Posted on April 23, 2014 by adgrant
High elevation limber pine stands (Pinus flexilis), prevalent in the Rocky Mountain region, face a new challenge that threatens their long-term viability in the region. White pine blister rust is an invasive fungi that came to North America from Asia in the late twentieth century. The fungus has dual obligate hosts in the limber pine and the gooseberry, and thus requires both species in order to spread and thrive.
Generally, the spores of the fungus grow through the stomata on the needles or through a wound in the bark of the tree. The fungus then grows into the branch, causing swelling. After a year or more, the fungus erupts through the bark in blister-like sacs that break, releasing the fungus’ spores to nearby hosts. The fungus may take up to a couple of years to kill an entire tree.
There are environmental, socio-economic, ecological, scientific, and aesthetic impacts of the loss of the highly valued high elevation limber pine and while the fungus is unlikely to wipe out entire limber pine stands it still impacts species distribution, population dynamics, and ecosystem functioning. Pine mortality caused by rust is predicted to convert currently forested slopes into treeless areas, affecting erosion and watersheds. Scientists also predict that mortality caused by the white pine blister rust will overall increase homogeneity in state forests and reduce biodiversity.
Scientists have been investigating the types and frequencies of white pine blister rust resistant limber pines in hopes of developing a preemptive conservation plan to enhance the limber pine populations overall resistance to the pathogen. In a recent article in the journal Phytopathology, forest researchers have identified a dominant gene which they have named Cr4. This gene was found to be present in anywhere from 0.5% to 14% of recently infested limber pine populations.
There is immense ecological value to the identification of resistance genes early on in the process of fungus infestation. The discovery enables the Forest Service to optimize cost effective management strategies.
http://www.fs.fed.us/rm/highelevationwhitepines/Threats/blister-rust-threat.htm
http://www.fs.fed.us/rm/highelevationwhitepines/images/threats/Threats_WPBR_Photos/PIFLstemcanker_Burns.jpg
http://www.fs.fed.us/rmrs/topics/resistant-allele/
Category: Rocky Mountain Issues, Uncategorized
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