Anti-TMGMV polyclonal antibody [AP]

The tobamoviruses tobacco mild green mosaic virus (TMGMV) and tobacco mosaic virus (TMV) differ in their behavior in Nicotiana megalosiphon. Both viruses induce necrotic lesion formation in the inoculated leaves, but only TMV moves from the initially infected (necrotic) areas and is able to spread systemically, overcoming the hypersensitive response. The appearance and growth of necrotic local lesions induced by TMV or TMGMV in N. megalosiphon were shown to follow similar kinetics; however, virus accumulation in the local lesions was about five times greater for TMV than for TMGMV. In accordance with this, TMV replicated to much higher levels than TMGMV did in N. megalosiphon protoplasts. In N. tabacum 'Xanthi-nc,' a hypersensitive host for both viruses that was used as a control, no difference was observed in the kinetics of local lesion development nor in virus accumulation, either in local lesions or in protoplasts, for TMV or TMGMV. Thus, the ability of TMV, but not of TMGMV, to overcome the hypersensitive response of N. megalosiphon does not appear to be related to differences in the elicitation of the hypersensitive response but rather to the differential effect of a second resistance factor over the multiplication of TMGMV but not of TMV.

Conspicuous viral symptoms were seen on Tabernaemontana divaricata, a member of the family Apocynaceae, grown in a commercial nursery, in Israel. The symptoms varied widely and included chlorotic ringspots and banding, oak-leaf patterns and mosaic. At the end of the winter, large yellow spots, which later became necrotic, appeared on fully expanded leaves. The necrotic zones later fell out, leaving "shot holes". Preliminary analysis suggested that the disease was associated with a tobamovirus. Particles typical of a tobamovirus were observed by electron microscopy only in samples taken from symptomatic leaves. A partial segment of the 5'-terminus of the viral RNA, which comprised of 533 by was cloned and sequenced. Comparison of the predicted amino acid sequence with those of other tobamoviruses revealed 94% identity with Tobacco mild green mosaic virus (TMGMV) genome. Primers specific to the coat protein (CP) gene of TMGMV used in a reverse transcription-polymerise chain reaction assay (RT PCR) gave an expected amplification product of 455 bp. The amino acid composition of the cloned CP gene, which shows a complete identity to that of TMGMV confirmed the identity of TMGMV infecting Tabernaemontana. Polyclonal antibodies prepared against the virus and used in double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) enabled specific detection of the virus in crude sap extracted from T. divaricata and mechanically inoculated indicator plants. This is the first report of TMGMV infection in Tabernaemontana and the first incidence of the virus in Israel.