ISHS Acta Horticulturae 377: VIII International Symposium on Virus Diseases of Ornamental Plants
POTYVIRUS RESISTANCE DERIVED FROM ANTISENSE RNA AND NATIVE OR CHIMERIC COAT PROTEIN GENES |
| Authors: | J. Hammond, K. K. Kamo |
| Abstract:
An antisense (AS) RNA construct consisting of the C-terminal portion of the coat protein (CP) gene and complete 3' non-coding sequence of bean yellow mosaic virus (BYMV), and driven by the cauliflower mosaic virus (CaMV) 35S promoter, was used to obtain transgenic Nicotiana benthamiana plants by Agrobacterium-mediated transformation. Other plants were transformed with constructs designed to express the BYMV CP gene or chimeric CP genes. The original transformants from each construct were allowed to self. R1 plants carrying the introduced gene were selected on the basis of polymerase chain reaction (PCR) and/or ELISA (for CP-expressing plants) with monoclonal antibodies. Homozygous R2 plants expressing AS RNA displayed a range of resistance, from minimal to apparent immunity from infection by BYMV; no resistance was observed to other potyviruses. Plants expressing native BYMV CP also showed a range of resistance, with a minimal degree of resistance to other potyviruses. Both AS and CP plants displayed two types of resistance; to initial infection, and/or to replication or movement. Chimeric CPs, with the N-terminal domains of BYMV fused to the C-terminal domains of pepper mottle potyvirus or zucchini yellow mosaic potyvirus, differed in their response to challenge with several potyviruses. At least one transformant of each chimeric CP showed milder symptoms than non-transgenic controls when inoculated with BYMV, and some resistance to potato virus Y. Deleted constructs are being prepared with the aims of separating the two types of resistance, determining the mechanisms of resistance, and which domains confer viral specificity. | |
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