A host plant is typically transformed with a construct whose gene is obtained from the pest of interest. When that gene is transcribed in the plant it produces a double stranded RNA (dsRNA) corresponding to the targeted pest gene. The plant recognizes that dsRNA as a foreign molecule and degrades it through a well-characterized process leading to formation of small polynucleotides called small interfering RNAS (siRNAs).
Pests feeding on the host plants ingest those siRNAs that subsequently trigger the pest to degrade the target gene within the pest. Thus, a pest gene critical to the functioning of the pest is “silenced” in the pest, rendering the plant resistant. “Venganza” means revenge or retribution in Spanish. The plant is getting revenge by inactivating the pest with its own gene. Hence, the name of our company.
Proof of concept for the Venganza technology has been demonstrated in three different plant species (tobacco, soybean and potato), with each species resistant to one or more of Phytophthora nicotianae, P. sojae, P. infestans and Peronospora tabacina. Identification of the appropriate siRNAs in the host plants and in re-isolated fungi demonstrates that the underlying mechanism of action for the Venganza technology is gene silencing or RNA inteference (RNAi).
Target genes and corresponding construct sequences are being developed to convey resistance to a single pest species or to several diverse pests simultaneously. For example, using a single construct, resistance in tobacco was achieved against fungi from different families (i.e. Peronospora tabacina and Phytophthora nicotianae).
Multi-pest resistance in plants transformed with unique constructs of multiple target genes is being tested for resistance to, for example, fungi and insects. Data thus predict the general applicability of this proprietary approach to many pests and pathogens of many food and fiber crops.