ZERBINI, Poliane Alfenas.; BRAZ, Antonio Sergio Kimus.; TORRES, Leonardo B.; SANTANA, Enilton Nascimento de.; NASCIMENTO, Ana Verônica Silva do.; OTONI, Wagner Campos.; CARVALHO, Murilo G.; ZERBINI JUNIOR, Francisco Murilo.
Abstract:
Sixteen transgenic yellow passionfruit (Passiflora spp.) plants (R0) were obtained which express a non-translatable
transgenic RNA corresponding to the 3’ region of the NIb gene and the 5’ region of the CP gene, derived from the genome of
a Brazilian isolate of Cowpea aphid-borne mosaic virus (CABMV). The transgenic plants were propagated by stem
cuttings and challenged by sap inoculation with isolates CABMV-MG1 and CABMV-PE1. One transgenic plant (TE5-10)
was resistant to the isolate CABMV-MG1, but susceptible to CABMV-PE1. The remaining transgenic plants developed
systemic symptoms, equal to non-transformed plants, when inoculated with either isolate. The absence of virus in TE5-10
plants was confirmed by indirect ELISA. Transcription analysis of the transgene demonstrated that the TE5-10 plant did
not accumulate transgenic mRNA, even before inoculation. After inoculation, viral RNA was only detected in plants
inoculated with CABMV-PE1. These results confirm that the transgenic plant TE5-10 is resistant to isolate CABMV-MG1,
and suggest that the resistance mechanism is post-transcriptional gene silencing, which is already activated in the transgenic
plants before virus inoculation.
