Replicability of an ALSV-based VIGS vector in wild strawberry and fenugreek

Nowadays, due to the intrinsic ability of viruses in transferring genes and their incorporation into the host genome, they are used as a powerful tool for silencing and overexpression of different genes in plants. Virus-induced gene silencing (VIGS) is widely used in plant genetics for knocking genes down thanks to its ease of use and the short time required to generate the associated phenotype. Apple latent spherical virus (ALSV)-based vectors can be used for effective and stable VIGS in a broad range of plant families such as Brassicaceae, Rosaceae, Solanaceae, Fabaceae, Cucurbitaceae, Scrophulariaceae and so forth. However, to the best of our knowledge, there is no report on the replicability and applicability of this viral vector in wild strawberry and fenugreek. In this research, we aimed to optimize and evaluate the propagation of an ALSV-based VIGS vector in these two horticultural plants.

The seeds from the accession Hawaii-4 (H4) (PI551572) of the woodland (wild) strawberry, Fragaria vesca L. ssp. vesca f. alba (Ehrh.) Staudt, and Trigonella foenum-graceum (fenugreek) were planted and thereafter, the grown plants were used for inoculation. The Chenopodium quinoa was used as a propagation mediator plant. To do this, viral plasmids pEALSR1 and pEALSR2 were inoculated into C. quinoa plants by two methods, carborundum-mediated and injection-by-syringe.

The C. quinoa plants showed virus-induced chlorosis and necrosis symptoms 3-5 week after inoculation. Subsequently, the extract of infected plant tissues was inoculated onto the leaves of wild strawberry and fenugreek plants. Total RNA were extracted from all inoculated leaves and used for RT-PCR. Results indicated that a 211 bp fragment of pEALSR2 plasmid was amplified using RNA of all inoculated plants.

It was concluded that this ALSV-based vector was introduced and propagated in the target plants and can be used successfully as a VIGS vector in these plants for gene silencing and overexpression purposes.