Genetics of plant adaptation to serpentine soils

Serpentine soils provide a wonderful model for the study of adaptive evolution in nature.  Their unique chemical and physical properties (e.g., low in available calcium, high in magnesium, low water holding capacity) are responsible for the evolution of their unique flora, often including many rare and endemic plant species.  By identifying pairs of plant taxa, one of which is adapted to serpentine soils and the other of which is not, Doug Schemske and I are setting up QTL mapping pedigrees of plants (e.g., Linanthus parviflorus, L. bicolor) that segregate for tolerance to serpentine soils.  In addition, I have screened Arabidopsis mutants for their ability to grow in defined nutrient solutions with very low levels of calcium and very high levels of magnesium.  I recently identified a recessive mutation in CAX1 which greatly increases survival and growth on loCa-hiMg solutions.  I am developing QTL mapping populations in Streptanthus glandulosus, an Arabidopsis relative that occurs both on and off serpentine soils.  Kristy Brady, a grad student in my lab, is working on the ecology, physiology, and genetics of serpentine soil tolerance in Mimulus guttatus.

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Last revised: 6-November-2005