Dr. Alexander Koch
alkoch@uoguelph.ca
Research Interests
I am interested in topics such as evolution, population genetics
and ecology - especially for symbiotic interactions. The ultimate
goal of any evolutionary ecologist is trying to understand how and
why organisms are growing and replicating where they occur, and
to understand (or even be able to predict) the complexities that
we encounter wherever we look in nature.
Arbuscular mycorrhizal fungi (AMF) are a group of soil fungi that
possess a highly interesting biology and a special genetic system.
The fungi are coenocitic organisms and many nuclei coexist in a
common cytoplasm. The debate about whether or not these nuclei are
genetically indentical (homokaryosis) or not (heterokarysis) has
split the AMF-research community. The proponents of heterokaryosis
so far have presented the more convincing data; to the opponents
of multiple genomes I would teaslingly ask: How could one EVER proof
that two things are identical??? But time will tell and the truth
will come to light – and during this process probably a lot
of new insights into the genetics of these fungi.
AMF are generally thought to be plant mutualists, enhancing plant
growth, improving resistance to pathogens or water stress, and are
able to increase floristic diversity. How these mutualisms have
been maintained with success for so long is still a major and unsolved
question. Yet, AMF have frequently no apparent negative effects
on plant growth and clearly the net outcome to the symbiosis is
dependent on the identity of the interacting partners as well as
the environmental conditions. AMF are putative ancient asexuals;
certainly they are ancient, as they formed the symbiosis with roots
of the first land plants some 400,000,000 years ago; whether they’re
truly asexual… this is yet to be seen and may well be linked
with the above mentioned debate. My guess is rather not. Maybe
they will turn out to be “asexual parasexuals”.
Currently I’m doing a post-doc to investigate the relative
importance of intra- and interspecific diversity in a community
of arbuscular mycorrhizal fungi (AMF). Past research has shown considerable
genetic and phenotypic diversity within AMF populations (even within
individuals), but a formal test on whether within and among morpho-“species”
(…whatever that means, if anything…) variability are
equally important has in my opinion still not been appropriately
been answered. What do I mean by “important”? Important
could mean, the way the fungi alter plant growth or the way fungi
grow themselves – both of which could be ecologically important.
Varying levels of AMF diversity could also affect communities in
such a way that a non-native species may have a higher chance of
establishing and successfully out-competing local species. Thus
AMF may also affect the resistance of ecosystems to potential invaders
- a question which is still largely unanswered.
Curriculum Vitae
Born on (Friday!-) July 13th, 1973 in Basel, Switzerland.
1990-1991 Exchange year in Foley, Alabama. Graduation
at Foley High School.
1993 - 1998 Studies in Biology and Mathematics
at the University of Basel, Switzerland.
1998 - 1999 Diploma thesis on the "Resource
capture of the parasitic plant Cuscuta campestris" under the
supervision of Ian Sanders.
2000 - 2006 PhD Studies on the link between population
genetics and ecology in the AMF species Glomus intraradices, under
the supervision of Ian R. Sanders at the University of Lausanne,
Switzerland.
2006 - Postdoc in the research lab of John
Klironomos at the University of Guelph.
Personal Interests
For 16 years I have been a passionate rock climber and still love
to get outside, sniff fresh air, and have fun – virtually
- “on the rocks”. Rock climbing for me is more than
just “sport”, it’s emotion, concentration, weather,
temperature, mood, nerves, centre, confidence, finding the “magic
touch” and much more… certainly a good self-experience
where you learn a lot about yourself... most of all it’s great
fun.
I also like to go snow skiing, play piano, listen to music, play
chess or shoot some pool, watch movies or visit an art museum.
Publications:
2006
Koch, A.M., Croll, D., Sanders, I.R., 2006. Genetic variability
in a population of arbuscular mycorrhizal fungi causes variation
in plant growth. Ecology Letters 9, 103-110.
[URL]
2004
Koch A.M., Binder C., Sanders I.R., 2004. Does the generalist parasitic
plant Cuscuta campestris selectively forage in heterogeneous plant
communities? New Phytologist 162, 147-155.
[URL]
Koch, A.M., Kuhn, G., Fontanillas, P., Fumagalli, L., Goudet, J.,
Sanders I.R., 2004. High genetic variability and low local diversity
in a population of arbuscular mycorrhizal fungi. Proceedings
of the National Academy of Sciences of the United States of America
101, 2369-2374. [URL]
2003
Sanders, I.R., Koch, A., Kuhn, G., 2003. Arbuscular mycorrhizal
fungi: genetics of multigenomic clonal networks and its ecological
consequences. Biological Journal of the Linnean Society
79, 59-60. [URL]
Alex
in the greenhouse 
The
magic brew 