title: Cross-protection in Arabidopsis against crucifer tobamovirus Cg by an attenuated strain of the virus.
abstract: SUMMARY Cross-protection is a procedure that has been utilized to protect crops against virulent strains of viruses by pre-treatment with closely related attenuated strains of the virus. We constructed a mutant of crucifer tobamovirus Cg, which is analogous to L(11)A, an attenuated strain of Tomato mosaic virus-L (ToMV-L). This mutant, named CgYD, caused few disease symptoms and could spread throughout Arabidopsis thaliana Col-0 plants. Initial infection with CgYD was shown to efficiently cross-protect against a challenge with wild-type Cg. Thus, we have established in Arabidopsis a powerful system for investigating mechanisms of cross-protection. Using this system, we showed that cross-protection was not overcome, even if a higher concentration of the virion, or purified virion RNA, were used in the challenge. We also demonstrated that cross-protection requires that the second virus be very similar in sequence to Cg, which is a characteristic of RNA silencing. However the RNA dependent RNA polymerase SDE1/SGS2 associated with post-transcriptional gene silencing was not required for cross-protection.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kurihara
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Watanabe