Effect of defective interfering RNAs on the vertical transmission of Tomato black ring virus

Viruses are thought to be the ultimate parasites, using host resources for multiplication. Interestingly, many viruses also have their own 'parasites', such as defective interfering RNAs (DI RNAs). One of the plant viruses whose infection can be accompanied by subviral RNAs is the Tomato black ring virus (TBRV). DI RNAs associated with the TBRV genome were generated de novo as a result of prolonged passages in one host. DI RNAs modulate the TBRV accumulation and the severity of the symptoms induced on the infected plants. In this study, we have addressed the question of whether DI RNAs can also affect TBRV vertical transmission through seeds. The experiments were conducted using the TBRV-Pi isolate and Chenopodium quinoa plants. C. quinoa plants were infected with TBRV-Pi with and without DI RNAs. Overall, 4 003 seeds were tested, and the analysis showed that the presence of DI RNAs made the TBRV-Pi seed transmission 44.76% more efficient. Moreover, for the first time, we showed that DI RNAs are being transferred from generation to generation.