Hypotheses for the evolution of actinorhizal symbioses
Actinorhizal symbioses include symbiotic associations between actinomycetes of the genus Frankia and host plants belonging to 24 genera distributed among eight higher plant families. Although all host plant species are woody dicots, there is no close phylogenetic affinity among most host plant groups. Nor is there agreement among actinorhizal biologists as to whether host plants are likely to have evolved from a common nodulated ancestor or whether symbioses have more likely arisen independently more than once resulting in the current diversity of host plant species. Knowledge of the phylogenetic relationships among actinorhizal plants as well as comparative analyses of nodule structure and function should contribute to the formulation of working hypotheses for the evolution of actinorhizal symbioses.
KeywordsHost Plant Species Frankia Strain Actinorhizal Plant Root Hair Infection Tricolpate Pollen
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- 2.Berry, A. & Sunell, L.A. (1990) in The Biology of Frankia and Actinorhizal Plants, eds. Schwintzer, C.R. & Tjepkema, J.D. (Academic Press, New York), pp 61–81.Google Scholar
- 3.Cronquist, A. (1988) The Evolution and Classification of Flowering Plants (The New York Botanical Garden, Bronx, NY).Google Scholar
- 9.Silvester, W.B., Harris, S.L. & Tjepkema, J.D. (1990) in The Biology of Frankia and Actinorhizal Plants, eds. Schwintzer, C.R. and Tjepkema, J. D. (Academic Press. New York) pp 157–176.Google Scholar