MSc Exit Seminar – Reem Merwass (AbouHaidar lab)

MSc Exit Seminar

Thursday May 12^th, 1:10 pm – Earth Sciences Centre, Rm. 3087

Reem Merwass (AbouHaidar lab)

“Requirement(s) for the Replication of Lucerne Transient Streak Virus Satellite RNA“

Abstract

The satellite RNA of Lucerne Transient Streak Virus (LTSV) is a 322-nucleotide, single-stranded circular RNA with a high degree of base-pairing (70%) that has a rod-like structure very similar to that of viroids. As it does not encode any translation products and cannot replicate independently of a helper virus, the satellite RNA is proposed to rely on viral-encoded proteins for the replication and cell-to-cell movement that facilitate its systemic infection in a host. To investigate the requirements for replication and cell-to-cell movement of the LTSV satellite RNA, transgenic plant systems were generated to express the viral RNA-dependent RNA polymerase. Results of infectivity assays of these transgenic lines demonstrated for the first time that the viral encoded RNA-dependent RNA polymerase is necessary and sufficient for the replication of LTSV satellite RNA, and no additional viral-encoded protein products for its cell-to cell or systemic transport are needed. Since some studies of cell-to-cell movement in plants indicate that plasmodesmata have a molecular size exclusion limit between 700 and 800 daltons, the LTSV satellite RNA (with a molecular size of approximately 109 kDa) may be able to interact with plasmodesmata in such a way as to allow for its movement without the assistance of other viral or host-encoded proteins.