Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA

Biogenesis And Function Of Virus-Derived Small RNAs In Plants

Zhixin Xie¹ , Xiaopeng Qi¹ , Forrest S. Bao² , Xing Qi¹ , Kanhav Khanna¹

¹  Department of Biological Sciences, Texas Tech University, Lubbock, Texas 79409, USA

²  Department of Computer Science, Texas Tech University, Lubbock, Texas 79409, USA

Most eukaryotes possess a remarkably conserved RNA silencing system in which double-stranded RNA (dsRNA) precursors are processed into 21- ~24-nucleotide (nt) small RNAs that regulate the activity of their targets in a sequence-specific manner. One of the well established roles of RNA silencing is its function as a defense mechanism against an invading virus in plants and some animals. On the other hand, many viruses encode proteins that suppress activities of the host silencing machinery, reflecting a viral counter-defense strategy evolved during the long-standing virus-host arms race. Using tobacco mosaic virus and Arabidopsis as a model system, we have recently analyzed the viral small RNA profiles in the infected host by a deep sequencing approach. Large sets of viral small RNA reads, mostly of 21- and 22-nt in size and originating predominately from the genomic sense RNA strand, were captured at an early infection stage from both wild type Arabidopsis and mutant plants defective in certain RNA silencing components, generating a high-resolution, near-saturated small RNA map for a plant virus. Our work revealed several features of viral small RNA population that provide mechanistic insights on their biogenesis and potential biological functions.