title: Viroid intercellular trafficking: RNA motifs, cellular factors and broad impacts.
abstract: Viroids are noncoding RNAs that infect plants. In order to establish systemic infection, these RNAs must traffic from an initially infected host cell into neighboring cells and ultimately throughout a whole plant. Recent studies have identified structural motifs in a viroid that are required for trafficking, enabling further studies on the mechanisms of their function. Some cellular proteins interact with viroids in vivo and may play a role in viroid trafficking, which can now be directly tested by using a virus-induced gene silencing system that functions efficiently in plant species from which these factors were identified. This review discusses these recent advances, unanswered questions and the use of viroid infection as an highly productive model to elucidate mechanisms of RNA trafficking that is of broad biological significance.
authors: Department of Plant Cellular and Molecular Biology and Molecular, Cellular and Developmental Biology Program, Ohio State University, 207 Rightmire Hall, 1060 Carmack Road, Columbus, 43210 USA; E-Mail:  takeda.7@buckeyemail.osu.edu.
authors: Ryuta
authors: R
authors: Takeda
authors: Biao
authors: B
authors: Ding