Abstract
cDNA macroarray systems were applied to compare the gene expression profile of Fix- mutant Ljsym75 nodules with that of wild-type Gifu nodules in order to reveal host plant genes related to nitrogen fixation. In total 18,432 non-redundant clones, expressions of 56 genes were reduced and 45 genes were enhanced in sym75 nodules significantly compared with those in Gifu nodules. These results were mostly confirmed by northern blot analysis. Genes of which expression was lower in sym75 nodules were represented by nodulins such as leghemoglobin and Nlj21, enzymes involved in carbon and nitrogen metabolism such as sucrose synthase, phosphoenolpyruvate carboxylase and asparagine synthetase, membrane transport proteins such as aquaporin, pathogenesis-related proteins, and enzymes involved in phytohormone metabolism. On the contrary, enzymes concerning with senescence such as cysteine proteinase and metal binding proteins such as metallothionein were included in those of which expression was higher in sym75 nodules.
