Expression of farnesyl diphosphate synthase gene (fps) in Nicotinan tabacum hairy root via Ri-mediated transformation

Abstract

To improve phytoalexin synthesis capability of hairy roots, farnesyl diphosphate synthase gene (fps) of Mentha spicata L. was transferred into tobacco via Ri-mediated transformation. The engineering Agrobacterium rhizogenes strain Ar1334 harboured the binary vector pBinARfps, in which the fps cDNA was placed under 35S promoter. The leaf explants of K326 co-cultured with Ar1334 were transformed on MS medium to induce hairy roots. Among the 18 lines of hairy root induced, 4 lines showed some kanamycin (20 mg·L-1) resistance. All the transgenic hairy root lines showed typical hairy root characteristics on MS medium without any plant hormone. Polymerase chain reaction and Southern blot revealed the foreign gene fps was intergrated into these 4 lines. Northern blot analysis indicated that the foreign fps gene was expressed at the transcriptional level. Transgenic hairy root lines showed higher FPS activity than the control and disease challenge also proved that the juice of transgenic hairy roots could inhibit the growth of Alternaria alternata. This result proved that foreign fps gene expression could improve the accumulation of resistance substance in hairy roots in vitro culture.

Keywords

• <italic>Nicotiana tabacum</italic>
• farnesyl diphosphate synthase
• hairy root
• <italic>Alternaria alternata</italic>