Integrated functional genomics to define the plant's function in symbiotic nodulation

摘要

Recent advances of high throughput DNA sequencing, bioinformatics, robotics, BAG libraries, microarrays, insertional mutagenesis as well as promoter trapping open the opportunity for an integrated function and structure analysis of the genomes of soybean (Glycine max) and the model legume Lotus japonicus. We are specifically interested in the plant's role during the establishment of nodule morphogenesis, and the genes shared during seemingly related developmental programs leading either to nodule or lateral root formation. Plant mutations were induced using EMS, fast neutron deletion as well as insertion mutagenesis. Single recessive loci were mapped using molecular markers, which were used to isolate soybean BAG clones to generate contigs spanning mutant deletions. Special emphasis was given to the Nts-1 locus of soybean that governs autoregulation of nodulation. Expression analysis of nodulation events using 4200 micro-arrayed root ESTs was initiated to detect gene products temporarily expressed during early nodulation. Insertion of a promoter-less gus-reporter gene into Lotus japonicus allowed the isolation of activated plant lines that showed development specific gus-gene expression. Isolation of flanking DNA sequences provided information of potential promoters and gene function as well as providing a link between structural and functional elements of nodulation-related genes. Evidence suggests that many nodule initiation functions evolved or are shared with lateral root related processes.The possibility exists that several non-legumes share such genes.