Resistance induced by viral sense, anti-sense, and hairpin constructs against beet curly top virus and beet curly top Iran virus

RNA silencing-based antiviral breeding is a promising strategy for developing virus-resistant plants.

This study employed viral sense, anti-sense, and hairpin constructs to induce resistance against beet curly top virus (BCTV) and beet curly top Iran virus (BCTIV).

For this purpose, a 120-bp conserved sequence of Rep- and C2-BCTV and a 222-bp conserved sequence of CP-, Reg-, and MP-BCTIV were selected for construct production. The efficiency of constructs was investigated in transient expression in Nicotiana benthamiana and sugar beet plants and stable expression in N. benthamiana.

In transient expression, all designed constructs induced effective resistance to BCTV and BCTIV; the hairpin constructs were more effective against both viruses. The stability of the achieved resistance by hairpin constructs was also confirmed in the T1 generation of transgenic plants.

This study showed that employing conserved coding sequences of BCTVs leads to effective resistance against BCTVs infection. The lack of protein production from transgene and degradation of its transcript due to the gene silencing mechanism makes this method safe for biosecurity. In stable transformation, the inheritance of induced resistance against BCTVs was confirmed in the T1 generation. These advantages make this mechanism commercially useful for the production of resistant plants to viruses.