ISHS Acta Horticulturae 432: IX International Symposium on Virus Diseases of Ornamental Plants
RESISTANCE TO VARIOUS POTYVIRUSES IN TRANSGENIC PLANTS EXPRESSING DIFFERENT FORMS OF POTYVIRUS COAT PROTEIN GENE. |
| Author: | J. Hammond |
| Abstract:
Two essentially native bean yellow mosaic virus (BYMV), and two chimeric coat protein (CP) gene constructs were separately used to create transgenic Nicotiana benthamiana by Agrobacterium-mediated transformation. One BYMV construct (CP-1 plants) had an untranslated leader sequence and 14 amino acids from nopaline synthase fused in-frame to the N-terminus of the BYMV CP, while the second (CP-2 plants) had a short artificial leader and initiation codon derived from an oligonucleotide; each included the complete BYMV 3' non-coding sequence. The chimeric CP genes had the artificial leader and N-terminal domain of CP-2 fused in-frame to the C-terminal domain and 3' non-coding region of potato virus Y (PVY; Pe plants) or zucchini yellow mosaic virus (ZYMV; ZY plants). Transgenic plants expressing serologically detectable levels of CP were self-fertilized, and homozygous R2 populations challenged by inoculation with BYMV, PVY, pepper mottle virus (PepMoV), tobacco etch virus (TEV), turnip mosaic virus (TuMV) and tobacco vein mottling virus (TVMV). Lines transformed with each construct were at least partially resistant to BYMV infection. Some lines showed resistance to initial infection, while others recovered from infection in later growth and were apparently resistant to either virus replication or transport. Both types of resistance were observed in some lines. Some of the Pe lines (BYMV/PVY chimeric CP) recovered from PVY infection, while some CP-1 and Pe lines were partially resistant to infection with TuMV. All lines displayed a delay in symptom production and/or reduced symptom severity with TVMV. None of the lines had any significant resistance to either TEV or PepMoV. Virus preparations purified from transgenic plants were assayed by ELISA and Western blotting to determine the extent of transgene CP incorporation into virions. There was no apparent correlation between the extent of transcapsidation and the degree of resistance observed. | |
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