The mutant makes small, white nodules and has defects in nitrogen fixation. It can induce MtLEC4 and ENOD2 but not MtN31, MtCAM1, or MtLB1. The mutant forms infection threads that proceed through the cortical cells and produce limited nodule-like structures. The infection threads are indistinguishable from those of wild-type plants. It is unknown whether bacteria can differentiate into bacteroids. The mutant creates larger nodule-like structures than those induced by early infection mutants. Bacterial penetration into epidermal cells and into the outer cortical cells surrounding the nascent nodule of mutant plants is morphologically indistinguishable from those in wild-type plants. Bacterial colonization of nodule parenchyma cells is also indistinguishable between mutants and wild type.
Single gene targeted?
yes
Extra Information
The dnf1 mutant is defective in the ability to elicit nifH expression.
Mutagenesis Method
FNB
Mutant Class
Nod+Fix-
Allelism
not allelic to other DNFs
The earliest development stage known to be affected
Plant and Bacterial Symbiotic Mutants Define Three Transcriptionally Distinct Stages in the Development of the Medicago truncatula/Sinorhizobium meliloti Symbiosis
