Mapping local and systemic symptom determinants of cucumber mosaic cucumovirus in tobacco.
Cucumber mosaic cucumovirus (CMV) can be divided into two subgroups, I and II. LS-CMV and most other subgroup II strains cause a mild, systemic mottle on tobacco and can induce a necrotic etching (necrotic rings) symptom on inoculated tobacco leaves. In contrast, Fny-CMV and most other subgroup I strains cause severe, systemic mosaic symptoms on tobacco, but do not induce the necrotic etching symptom. Full-length cDNA clones of all three genomic RNAs of LS-CMV were constructed and infectious RNAs were generated from these clones. Using pseudorecombinants constructed from the infectious transcripts of LS-CMV and Fny-CMV, we found that both RNAs 1 and 2 of Fny-CMV are involved in determining the severity of systemic symptom on tobacco, and that LS-CMV RNA 3 contains the determinant for the necrotic etching symptom. Chimeras formed between Fny- and LS-CMV RNA 3 were used to demonstrate that the inducer of the necrotic etching symptoms mapped to the 5' 618 nucleotides of LS-CMV RNA 3, and required sequences in both the 5' non-translated region, as well as the 3a gene of CMV.
Department of Plant Pathology, Cornell University, Ithaca, New York 14853.
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Zhang
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Handa
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Palukaitis
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017799:Cucumovirus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D017931:DNA Primers; D018076:DNA, Complementary; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010947:Plants, Toxic; D012367:RNA, Viral / Q000096:biosynthesis* / Q000737:chemistry; D011995:Recombination, Genetic; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014026:Nicotiana / Q000821:virology*
D017931:DNA Primers; D018076:DNA, Complementary; D012367:RNA, Viral