Abstract
We investigated the efficacy of self-complementary hairpin RNAs (hpRNAs) expression to induce RNA silencing in root system of a model legume Lotus japonicus using a hairy root transformation mediated by Agrobacterium rhizogenes. Transgenic lines that express β-glucuronidase (GUS) by constitutive or nodule-specific promoters were produced and supertransformed by infection of A. rhizogenes harboring constructs for the expression of hpRNAs with sequences complementary to the parts of GUS coding region to form transgenic hairy roots. The GUS activity in more than 60% of the hairy roots was drastically decreased or silenced almost completely. The silencing of GUS gene was also observed in symbiotic nodules formed on the hairy roots in both early and late stages of nodule organogenesis. These results indicate that transient RNA silencing by hairy root transformation provides a powerful tool for loss-of-function analyses of genes that function in roots and root nodules.
