Seminar: Two Persistent Viruses in Peppers: Evolution and Modification of Aphid Behavior
Date and Location
When (Date/Time)February 20, 2017, 3:35 PM - 4:30 PM
Where112 Buckhout Lab
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Most well studied plant viruses are acute viruses that cause disease in their host. However, plants are very frequently infected with cytoplasmic RNA viruses that persist for many generations through nearly 100 percent vertical transmission without producing any obvious symptoms. Movement between plant cells and transmission through grafting has not been observed in these persistent viruses; instead they are distributed to all host cells through host cell division.
Peppers are perennial plants, native to the Americas, and as domesticated plants human selection accelerated their evolution, so codivergent timelines should be easier to follow. Jalapeño peppers and bell peppers (Capsicum annuum) are all infected with Pepper cryptic virus 1 (PCV1) or Bell pepper endornavirus (BPEV), respectively. PCV1 belongs to the Partitiviridae family; its genome consists of two dsRNAs which encode the RNA-dependent RNA polymerase (RdRp) and the coat protein. BPEV belongs to the Endornaviridae family, with genomes containing a single open reading frame. To investigate the evolution of these two viruses, dsRNA was extracted from over one hundred different pepper cultivars/landraces/wild materials including C. annuum, C. chacoense, C. chinense, C. frutescens, C. pubescens, and C. bacccutum. The presence of BPEV and PCV1 was tested by RT-PCR using specific primers for each virus. The nucleotide sequence of the RT-PCR products was determined and their phylogenies have been analyzed.
The roles of plant persistent viruses in the ecology of their hosts have not been studied thoroughly, but their very long-term relationships with their hosts and their high level of vertical transmission imply beneficial interactions. Studying the aphid-virus interaction revealed the beneficial role of PCV1 for its Jalapeño host.