“…However, not all instances of cross-protection can be explained this way (Gerber & Sarkar, 1989;Zaitlin, 1976). Coat protein-mediated effects cannot explain cross-protection between viroid strains or protection against virus infection provided by most satellite RNAs, with the exception of turnip crinkle virus-satellite RNA interactions (Gallitelli et al, 1991;Manfre & Simon, 2008;Montasser et al, 1991;Niblett et al, 1978;Sayama et al, 1993Sayama et al, , 2001Tien & Wu, 1991).…”