Fig. 1.
Schematic of the experimental design of parallel and sequential transmission modes. Details of the two transmission modes are schematized as well as their expected outcome using infections lacking segments C and U4 as an example. For sequential transmissions, we show only the case where aphids first fed on plants infected with FBNSVC− and then fed on plants infected with FBNSVU4−.The age of test plants, the status and age of infections, and the durations of AAPs and of IAP are indicated. The parallel and sequential modes with no time-spacing treatments were performed during experiment 1, and the sequential modes with time-spacing treatments were performed during experiment 2 (the sequential with no time-spacing treatment was independently performed in both experiments). Each experiment was replicated twice. As mentioned in Materials and Methods, the parallel transmission mode implies separate acquisition and inoculation of segments, whereas the sequential transmission mode implies temporally separated acquisition of segments but may allow concomitant inoculation.