Panorama of the whitebark pine seedling at the Dorena Genetic Resource Center (USFS)
Did you know that whitebark pine is the highest elevation tree here in the Pacific Northwest? If you have driven the Rim Road of Crater Lake National Park, you may have noticed a huge gnarly tree lovingly known by few as the “Grandmother” whitebark pine. These trees withstand harsh winds and cold temperatures, giving them a krummholz or “crooked wood” appearance. Some grow nearly horizontal.
Zolton’s favorite whitebark pine at the rim of Crater Lake
As one of the few tree species that grow at high elevations, whitebark pine acts as an ecosystem foundation species, making it possible for other plants, fungi, and animals to utilize higher elevation environments. Growing together, a population of whitebark pines form ecological islands and promote biodiversity in subalpine areas. For example, the Clark’s Nutcracker and whitebark pine have been coevolving for eons. The Clark’s Nutcracker is the only bird that can break open the pine cones of whitebark pine. While the bird eats some of the seeds, it also cashes them and can disperse the seeds many miles away. Other species such as rodents and bears eat the seeds as well.
Much more research is needed to fully understand the ecological importance of whitebark pine in its characteristic ecosystem. However, recently whitebark pine research is focused on another interaction, that of whitebark pine with an invasive plant pathogen, white pine blister rust. Since the 1900s, this pathogen has dramatically reduced populations of whitebark pine and other 5-needle pines of North America. This means that whitebark pine populations and the biodiversity islands it forms at high elevations are in trouble.
Zolton with his experimental seedlings at Dorena.
Fortunately, some populations show natural resistance to the pathogen, and our guest, Zolton Bair from the department of Botany and Plant Pathology, is comparing the transcriptomes, the collection of genes expressed as RNA, of resistant and susceptible trees to understand tree defense against white pine blister rust. Be on the lookout for his dissertation defense this year!
As a teenager, Zolton loved collecting and identifying mushrooms. Through a class called magical mushrooms, mischievous molds he realized that fungi are very important to humans as food, medicine, and can be problematic for farmers. He became interested in plant pathology after conducting undergraduate research in a mycology lab that focused on the spread of fungal spores between agricultural fields.
Experimental plot: Keep off!
You do not want to miss this week’s episode of Inspiration Dissemination with our guest Zolton Bair. Tune into KBVR Corvallis 88.7 FM this Sunday January, 22 at 7 pm to hear about Zolton’s journey from barefoot mushroom hunting in Virginia to studying plant pathology here at Oregon State, and we promise you won’t be disappointed to learn more about the awesome tree story of whitebark pine.
Not a local listener? Follow this link to stream the show live.
Hi David,
Although the ecological importance of whitebark pine is fairly well understood, less is known about genetic resistance to white pine blister rust (WPBR). As for banana, I’m assuming you are referring to Panama disease, caused by another fungus (Fusarium). In both cases, if the virulent pathogen is capable of infecting one plant, it will also be able to infect other plants that do not have genetic resistance.
WPBR is caused by a fungus that is not native to the USA, but was introduced in the early 1900’s. Since the fungus had evolved to successfully attack white pines from Eurasia, it is also capable of infecting related American white pines. However, American white pines did not co-evolve with the fungus, and thus did not evolve genetic resistance to combat disease pressures. In this way, a newly introduced fungus can wipe out huge populations in a short period of time. This dynamic is often observed when an exotic pathogen is introduced to a new area, and is the reason why customs spends so much to prevent the spread of new invasive pests.
Panama disease of banana is a little different. Often times, when humans target desirable traits (yield, taste, seedless) for breeding, we can miss out on other valuable traits like disease resistance. Nowadays, virtually the entire banana industry depends on cloning of the Cavendish variety. As a result, massive monocultures of genetically identical bananas are planted, serving as a selection pressure for the evolution of a new virulent strain of the fungus. If the new strain can infect one banana plant, it can infect all the banana plants– therein lies the problem.
For WPBR, the root cause is that native trees have not evolved resistance against an invasive, non-native pathogen. For Panama disease, the main issue is that all bananas are clones, so if one plant is susceptible, they all are. Hope that helps!