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C M van Dun

Publications and source records attributed to C M van Dun.

6 recordsLinked to original sources
PubMed1991

Alfalfa mosaic virus RNA3 mutants do not replicate in transgenic plants expressing RNA3-specific genes.

The RNA3 of alfalfa mosaic virus (AIMV) encodes the P3 protein and the viral coat protein (CP). RNA3 molecules transcribed in vitro replicated in protoplasts and plants when inoculated in mixtures with AIMV RNA1, RNA2 and CP. Transcripts with a deletion or inversion in the P3 gene replicated well in protoplasts but not in transgenic plants transformed with the P3 gene. Transgenic plants expressing the CP gene became infected after inoculation with a mixture of RNA1, RNA2 and wild-type RNA3 transcripts without addition of CP to the inoculum. Transcripts with a deletion in the CP gene replicated at a reduced level in protoplasts but not in CP-transformed plants. This suggests that P3 and CP are both required for cell-to-cell spread of AIMV and that mutations in the inoculum RNA could not be complemented in trans by the wild-type chimeric nuclear genes.

Blotting, Northern↗
PubMed1988

Expression of alfalfa mosaic virus cDNA1 and 2 in transgenic tobacco plants.

Chimeric genes composed of DNA complementary to alfalfa mosaic virus (AIMV) RNAs 1 or 2, the CaMV 35 S promoter, and the nos polyadenylation signal were transferred to the genome of Nicotiana tabacum cv. Samsun NN by means of the Agrobacterium tumefaciens transformation system. Transformants contained intact copies of the viral genes and accumulated transcripts of approximately the size predicted from the cloning procedure. Using antisera raised against synthetic peptides corresponding to the C-terminal parts of AIMV P1 and P2, it was not possible to detect viral translation products in the transformants. However, transgenic protoplasts containing cDNA1 were able to complement an infection by the AIMV nucleoproteins containing RNAs 2 and 3, indicating that biologically active P1 accumulates in these protoplasts. Upon inoculation with AIMV strains 425 or YSMV, the cDNA1- and cDNA2-transformed plants became infected to a level similar to that of nontransformed or vector-transformed control plants.

DNA↗
PubMed1988

Transgenic tobacco expressing tobacco streak virus or mutated alfalfa mosaic virus coat protein does not cross-protect against alfalfa mosaic virus infection.

Transgenic tobacco plants expressing the coat protein (CP) genes of tobacco streak virus (TSV) and alfalfa mosaic virus (AIMV) were used in studies on cross-protection and genome activation. Plants expressing the TSV CP gene were highly resistant to infection with TSV nucleoproteins but were susceptible to infection with AIMV nucleoproteins. Moreover, these plants could be infected with a mixture of AIMV RNAs 1, 2, and 3 in contrast to the nontransformed control plants. This demonstrates that the endogenously produced TSV CP is able to activate the AIMV genome but does not cross-protect against this virus. Conversely, it was shown that plants expressing the AIMV CP gene did not resist TSV infection. Transgenic tobacco plants transformed with an AIMV CP gene with a frame-shift mutation in the reading frame were found to accumulate viral transcripts to a level similar to that obtained in plants expressing a wild-type AIMV CP gene. However, these plants did not produce detectable amounts of viral protein and showed no resistance to infection with AIMV nucleoproteins in contrast to transgenic plants accumulating wild-type AIMV CP. This demonstrates that it is the CP that is responsible for cross-protection in transgenic plants and not the chimeric CP mRNA.

Capsid↗
PubMed1988

Transgenic tobacco plants accumulating tobacco rattle virus coat protein resist infection with tobacco rattle virus and pea early browning virus.

Transgenic tobacco plants expressing the coat protein (CP) gene of tobacco rattle virus (TRV) strain TCM were found to be resistant to infection with the homologous virus but not to infection with the PLB strain of TRV. The amino acid sequence identity between the CP of TRV strains TCM and PLB is 39% and the two CP genes do not cross-hybridize. On the other hand, there is extensive cross-hybridization between the CP genes of TRV-TCM and a Dutch isolate of pea early browning virus (PEBV). The transgenic plants accumulating TRV-TCM CP showed a considerable resistance to infection with PEBV.

Blotting, Northern↗