RDR6 knock down line potentiates the BaMV infection in newly emerging leaves of Nicotiana benthamiana
Y. HSU (1), M. Luo (1), Y. Huang (1), N. Lin (3) (1) Graduate Institute of Biotechnology, National Chung Hsing University, Taiwan; (2) Graduate Institute of Biotechnology, National Chung Hsing University, Taiwan; (3) Institute of Plant and Microbial Biology, Academia Sinica, Taiwan

Bamboo mosaic virus (BaMV) is a positive strand RNA virus in the genus Potexvirus. The infection pattern of BaMV in Nicotiana benthamiana is spreaded from inoculated leaves to upper leaves stepwise. In addition, BaMV cannot replicate in the newly emerging leaves (NEL) including shoot tip (ST), which would limit the application of BaMV-based vector for producing foreign proteins in whole plant. We have generated the transgenic N. benthmiana that expressed whole genome of BaMV. However, the nature of BaMV replication in BaMV transgenic plant is similar to mechanically inoculated non-transgenic one. To investigate what factors restrict the BaMV replication in young leaves, gene silencing factors including AGOs, RDRs or DCLs were tested. Virus-induced gene silencing technique was used to knock-down those core factors individually in BaMV-GFP transgenic N. benthamiana. The results indicated that BaMV RNA accumulation significantly increased in the upper leaves nearby ST when knocking-down AGO1 and RDR6. In addition, BaMV could successfully infect the NEL in RDR6 knock-down line, RDR6i. Therefore, we used RDR6i to cross with BaMV-GFP line 68-18 and BaMV-VP1 line 16-7, respectively. As expected, in these two hybrid F1 generations, both RNA and protein level of BaMV accumulation have significantly increased in upper leaves. These results are consistent with earlier research in Potato virus X, and this silencing signal-related mechanism could explain why many viruses are not able to invade the meristem of infected plants.

Abstract Number: P17-536
Session Type: Poster