T-DNA insertional mutagenesis will be used to identify plant genes that are expressed in a cell or tissue-specific manner in nodule and/or lateral root development and that control nodule and/or lateral root development. Binary vectors with a promoterless B-gluronidase (uidA, gus) reporter gene adjacent to the T-DNA border are used. Up to 2,500 transgenic lines will be generated by Agrobacterium transformation protocols and screened for GUS expression and mutant phenotypes. The most promising marker lines and mutants will be characterized by segregation analysis and expression patterns. cDNAs will be isolated and used to determine the genomic sequences responsible for the desired markers and mutations. Other types of characterizations will also be done.
Genetic and molecular mechanisms responsible for nodule formation will be investigated using the model legure Lotus japonicus. The approach used will involve using insertional mutagenesis with a T-DNA vector carrying a promoterless uidA tracer gene. The working hypothesis that nodule and lateral root development are related will be investigated also by the insertional mutagenesis approach. The success of this project will add significantly to insight into legume nodule formation, a process central to life as we know it
