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Successful nodulation of Casuarina by Frankia in axenic conditions
Author(s) -
Echbab H.,
Arahou M.,
Ducousso M.,
NourissierMountou S.,
Duponnois R.,
Lahlou H.,
Prin Y.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2007.03425.x
Subject(s) - frankia , axenic , biology , casuarina , symbiosis , inoculation , nitrogenase , botany , shoot , nodule (geology) , root nodule , horticulture , nitrogen fixation , bacteria , paleontology , genetics
Aims: In order to depict the fine interactions that lead to nodulation, absolute microbiological control of the symbiotic partners is required, i.e. the ability to obtain in vitro axenic nodulation, a condition that has never been fulfilled with the Casuarina–Frankia symbiosis . The effects of culture conditions on plant growth and nodule formation by Casuarina cunninghamiana were investigated. Methods and Results: Axenic (capped tubes with different substrates), and nonaxenic cultures (Gibson tubes, pot cultures) were tested. In axenic conditions, C. cunninghamiana , inoculated with Frankia , had poor growth and did not form nodules at 6 weeks. Plants cultivated in Gibson tubes reached the four axillary shoots stage within 6 weeks and formed nodules 4 weeks after inoculation. Sand‐pot cultures allowed us to relate the plant development stage at inoculation with nodulation. Conclusions: The sterile replacement of the cap by a plastic bag increased plant growth and enabled nodule formation 6 weeks after inoculation. The new system of plant culture allows the axenic nodule formation 6 weeks after inoculation. Nodulation behaviour is related to plant development and confinement. Significance and Impact of the Study: This axenic plant nodulation system is of major interest in analysing the roles of Frankia genes in nodulation pathways.