Composite Actinorhizal Plants with Transgenic Roots for the Study of Symbiotic Associations withFrankia

[摘要] More than 200 species of dicotyledonous plants belonging to eight different families and 24 genera can establish actinorhizal symbiosis with the nitrogen-fixing soil actinomyceteFrankia. Compared to the symbiotic interaction between legumes and rhizobia, little is known about the molecular basis of the infection process and nodule formation in actinorhizal plants. Here, we review a gene transfer system based onAgrobacterium rhizogenesthat opens the possibility to rapidly analyze the function of candidate symbiotic genes. The transformation protocol generates “composite plants” that consist of a nontransgenic aerial part with transformed hairy roots. Composite plants have already been obtained in three different species of actinorhizal plants, including the tropical tree speciesCasuarina glauca, the Patagonian shrubDiscaria trinervis, and the nonwoody plantDatisca glomerata. The potential of this technique to advancing our understanding of the molecular mechanisms underlying infection byFrankiais demonstrated by functional analyses of symbiotic genes.

[学科分类] 植物学