Differential replication in zucchini squash of a cucumber mosaic virus satellite RNA maps to RNA 1 of the helper virus.
ABSTRACT Cucumber mosaic virus (CMV) supports the replication and encapsidation of its satellite RNA, both in solanaceous and cucurbit host plants; however, different strains of CMV support the replication of satellite RNAs with different efficiency. In addition, replication of satellite RNA is very efficient in solanaceous host plants and generally poor in cucurbit host plants. The WL1-satellite (WL1-sat) RNA is an exception, and replicates to high levels in both solanaceous and curcubit host plants with most CMV strains as the helper virus. Two strains of CMV were used in this study: Fny-CMV, which replicates the WL1-sat RNA efficiently in all hosts tested; and Sny-CMV, which does not replicate the WL1-sat RNA to detectable levels in zucchini squash (Cucurbita pepo), but does replicate WL1-sat RNA efficiently in other hosts. Using pseudorecombinants constructed between Fny-CMV and Sny-CMV we have mapped to RNA 1 the ability to support the efficient replication of WL1-sat RNA in zucchini squash.
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ABSTRACT: Two groups of Cucumber mosaic virus (CMV) satellite RNAs (satRNAs), necrogenic and non-necrogenic, can be differentiated according to the symptoms they cause in tomato plants, a host in which they also differ in fitness. In most other CMV hosts these CMV-satRNA cause similar symptoms. Here, we analyse whether they differ in traits determining their relative fitness in melon plants, in which the two groups of CMV-satRNAs cause similar symptoms. For this, ten necrogenic and ten non-necrogenic field satRNA genotypes were assayed with Fny-CMV as a helper virus. Neither type of CMV-satRNA modified Fny-CMV symptoms, and both types increased Fny-CMV virulence similarly, as measured by decreases in plant biomass and lifespan. Necrogenic and non-necrogenic satRNAs differed in their ability to multiply in melon tissues; necrogenic satRNAs accumulated to higher levels both in single infection and in competition with non-necrogenic satRNAs. Indeed, multiplication of some non-necrogenic satRNAs was undetectable. Transmission between hosts by aphids was less efficient for necrogenic satRNAs as a consequence of a more severe reduction of CMV accumulation in leaves. The effect of CMV accumulation on aphid transmission was not compensated for by differences in satRNA encapsidation efficiency or transmissibility to CMV progeny. Thus, necrogenic and non-necrogenic satRNAs differ in their relative fitness in melon, and trade-offs are apparent between the within-host and between-host components of satRNA fitness. Hence, CMV-satRNAs could have different evolutionary dynamics in CMV host-plant species in which they do not differ in pathogenicity.Journal of General Virology 05/2011; 92(Pt 8):1930-8. DOI:10.1099/vir.0.032359-0 · 3.53 Impact Factor
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ABSTRACT: Two western strains of peanut stunt cucumovirus (PSV), strains W and BV-15, were unable to support the replication of two distinct PSV satellite RNAs (satRNAs), or infectious transcripts from full-length satRNA cDNA clones, in either tobacco or several leguminous host species. Furthermore, these two strains did not support the replication of cucumber mosaic virus satRNAs in tobacco. All 10 eastern PSV strains tested, on the other hand, efficiently supported PSV satRNA replication. Strains PSV-W acid BV-15 can be further differentiated from the eastern strain PSV-ER by Northern hybridization using cloned cDNA probes to PSV-ER RNAs 1, 2 and 3. Whereas the PSV-ER RNA-specific probes did not hybridize to any PSV-W RNAs, the PSV-ER RNA 3 probe hybridized strongly to PSV-BV-15 RNAs 3 and 4, thus supporting the finding that strain BV-15 is serologically closely related to the eastern strains. The PSV-ER RNA 2-specific probe, but not the PSV-ER RNA 1-specific probe, hybridized to the respective RNA of PSV-BV-15. The results of Northern hybridization with strain PSV-BV-15 support the contention that strain BV-15 represents a reassortant between western and eastern strains. The lack of cross-hybridization between PSV-ER and PSV-W RNAs in Northern hybridization at high stringency is consistent with finding that the percentages of nucleotide identity between the RNAs of strains PSV-ER and PSV-W were 75, 73, 74, and 74%, respectively, for RNAs 1, 2, 3, and 4. A procedure based on reverse transcription and the polymerase chain reaction (RT-PCR) was developed that utilized primers specific for PSV-ER RNA 2. Restriction enzyme digestion of the RT-PCR products generated distinct restriction patterns that clearly differentiated western from eastern strains.Phytopathology 04/1995; 85(4):502-507. DOI:10.1094/Phyto-85-502 · 2.75 Impact Factor
Canadian Journal of Plant Pathology 12/2009; June 1991(Vol. 13):155-162. DOI:10.1080/07060669109500951 · 0.99 Impact Factor