Natural Diversity of Frankia Strains in Actinorhizal Root Nodules from Promiscuous Hosts in the Family Myricaceae
AUTOR(ES)
Clawson, Michael L.
FONTE
American Society for Microbiology
RESUMO
Actinorhizal plants invade nitrogen-poor soils because of their ability to form root nodule symbioses with N2-fixing actinomycetes known as Frankia. Frankia strains are difficult to isolate, so the diversity of strains inhabiting nodules in nature is not known. To address this problem, we have used the variability in bacterial 16S rRNA gene sequences amplified from root nodules as a means to estimate molecular diversity. Nodules were collected from 96 sites primarily in northeastern North America; each site contained one of three species of the family Myricaceae. Plants in this family are considered to be promiscuous hosts because several species are effectively nodulated by most isolated strains of Frankia in the greenhouse. We found that strain evenness varies greatly between the plant species so that estimating total strain richness of Frankia within myricaceous nodules with the sample size used was problematical. Nevertheless, Myrica pensylvanica, the common bayberry, was found to have sufficient diversity to serve as a reservoir host for Frankia strains that infect plants from other actinorhizal families. Myrica gale, sweet gale, yielded a few dominant sequences, indicating either symbiont specialization or niche selection of particular ecotypes. Strains in Comptonia peregrina nodules had an intermediate level of diversity and were all from a single major group of Frankia.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=91602Documentos Relacionados
- Isolation of Frankia Strains from Alder Actinorhizal Root Nodules
- Diversity of Frankia Strains in Root Nodules of Plants from the Families Elaeagnaceae and Rhamnaceae
- Genetic diversity among Frankia strains nodulating members of the family Casuarinaceae in Australia revealed by PCR and restriction fragment length polymorphism analysis with crushed root nodules.
- Purification of Hemoglobin from the Actinorhizal Root Nodules of Myrica gale L.
- Hydrogenase in actinorhizal root nodules and root nodule homogenates.