Ken Keefover-Ring Ph.D.
Umeå Plant Science Centre
Department of Plant Physiology
Umeå University
90187 Umeå, Sweden
kenneth.keefover-ring@plantphys.umu.se
Curriculum Vitae
Research:
Chemical ecologists study plant secondary compounds and how these chemicals mediate interactions with other community members. Secondary compounds include such chemicals as essential oils (mono- and sesquiterpenes) and alkaloids (caffeine and nicotine). These chemicals were originally thought of as “secondary” because they are not necessary for plant primary metabolism, like proteins, DNA, or sugars. However, later we realized that plants use secondary chemicals for a variety of important functions, including deterring herbivores, attracting pollinators, and even inhibiting competition by other plants (allelopathy). Thus, these compounds can affect long term plant fitness.
For my Master's degree at the University of Colorado at Boulder I studied terpenoid chemistry and herbivores in the seed cones of ponderosa pine (Pinus ponderosa). This specialized group of insects lays eggs in or on green second-year cones and their larvae mine the cones' interior, destroying seeds and affecting tree reproduction.
Dioryctria abietella cone moth on ponderosa cone
My Ph.D. focused on essential oil polymorphisms of species in the Lamiaceae (Mint) family. Due to these polymorphisms, individual plants within a species have distinct chemical phenotypes (chemotypes) producing different essential oils, also called terpenes. These terpenes have differential effects on organisms such as pollinators, herbivores, and other plants. I use two primary study organisms, a Mediterranean native Thymus vulgaris or common thyme, and Monarda fistulosa, a North American species also known as wild bergamot or bee balm.
My postdoctoral work at the University of Wisconsin at Madison in the lab of Prof. Richard Lindroth involves studying the effects of artificial browsing, similar to that of a large herbivore on trembling aspen (Populus tremuloides). This project involves growing replicates of several different aspen genotypes, all originally collected from southern Wisconsin, in a common garden setting on the University of Wisconsin campus under different fertilizer treatments. To simulate browsing, we remove 50-75% of the above ground biomass on half of small trees by squeezing them with a needle-nose pliers and tearing. We then apply deer saliva to more closely mimic the conditions of natural herbivory. The different genotypes are then monitored for changes in nutrients (carbon and nitrogen) and secondary chemistry (phenolic glycosides and condensed tannins), and their ability to regrow biomass and leaf area lost to browsing.
I continue to work with the chemistry of the Salicaceae in northern Sweden in the lab of Dr. Benedicte Albrectsen at the Umeå Plant Science Centre. Here, I am using electrospray ionization (ESI) time-of-flight (TOF) LC-MS to characterize phenolic glycoside diversity in the Swedish Aspen (SwAsp) collection, which represents many genotypes of Populus tremula collected from throughout Sweden and in 21 species and subspecies of Salix.
Peer-Reviewed Publications:
Keefover-Ring K. In review. Making scents of defense: Larval fecal shield terpenes and herbivore-caused volatiles reflect aromatic host plant chemistry. Journal of Chemical Ecology
Keefover-Ring
K. and Linhart Y.B. 2010. Variable chemistry and herbivory in ponderosa
pine cones. International
Journal of Plant Sciences 171(3): 293-302
Keefover-Ring K, Thompson J.D., and Linhart Y.B. 2009. Beyond six scents: defining
a seventh Thymus vulgaris chemotype new to southern France
by ethanol extraction. Flavour
an
d Fragrance Journal 24: 117-122
Groendahl E., Ehlers,
B.K., and Keefover-Ring K. 2008. New cis-sabinene
hydrate chemotype detected in large thyme (Thymus pulegioides
L.) growing wild in Denmark. Journal
of Essential Oil Research 20: 40-41
Thompson J.D., Gauthier
P., Amiot J., Ehlers B.K., Collin C., Fossat J., Barrios V., Arnaud-Miramont F.,
Keefover-Ring K., and Linhart Y.B. 2007. Ongoing
adaptation to Mediterranean climate extremes in a chemically polymorphic
plant. Ecological Monographs
77(3): 421-439
Linhart Y.B., Keefover-Ring K., Mooney K.A., Breland B., and Thompson J.D.
2005. A chemical polymorphism in a multi-trophic setting: thyme monoterpene
composition and food web structure. American
Naturalist 166(4): 517-529
Non-peer Reviewed Publications:
Keefover-Ring K.
2007. Prairies
make good scents: Bee balm, a prairie native. The
Shortgrass Prairie Review 3(3): 8-9
Keefover-Ring K. 2006. Monarda fistulosa: Making good scents in Colorado. Aquilegia
30(2): 3-4