CONSTRUCTION OF A LOTUS-JAPONICUS LATE NODULIN EXPRESSED SEQUENCE TAGLIBRARY AND IDENTIFICATION OF NOVEL NODULE-SPECIFIC GENES

A range of novel expressed sequence tags (ESTs) associated with late d evelopmental events during nodule organogenesis in the legume Lotus ja ponicus were identified using mRNA differential display; 110 different ially displayed polymerase chain reaction products were cloned and ana lyzed. Of 88 unique cDNAs obtained, 22 shared significant homology to DNA/protein sequences in the respective databases. This group comprise s, among others, a nodule-specific homolog of protein phosphatase 2C, a peptide transporter protein, and a nodule-specific form of cytochrom e P450. RNA gel-blot analysis of 16 differentially displayed ESTs conf irmed their nodule-specific expression pattern. The kinetics of mRNA a ccumulation of the majority of the ESTs analyzed were found to resembl e the expression pattern observed for the L. japonicos leghemoglobin g ene. These results indicate that the newly isolated molecular markers correspond to genes induced during late developmental stages of L. jap onicos nodule organogenesis and provide important, novel tools for the study of nodulation.