Abstract
A plant hormone abscisic acid (ABA) inhibits nodule formation of Lotus japonicus. The five genes of L. japonicus were screened as ABA responsive gene by using cDNA macroarray of L. japonicus. Four of them, Class 1 chitinase (PR3), PR10.2 C Protein (PR10.2c), Chalcone synthase (CHS), and β-1,3-glucanase (Glu1), were involved in plant defense system and ORF2 bases 1807-2850 was unknown function.
Transformed hairy roots of L. japonicus were generated with anti-sense genes. The anti-sense hairy roots of LjGlu1) and CHS showed increased nodule number and enhanced nitrogen fixation activity. The anti-sense of ORF2 bases 1807-2850 also gave enhanced nitrogen fixation activity to the hairy roots. The expression level of these three genes in anti-sense hairy roots was 53% lower for LjGlu1, and around 30% lower for other two genes compared with those of wild type. In this study, RNAi transformed hairy roots harbouring RNAi constructs and nodule formation and nitrogen fixation were determined.
