Zinnen, Thomas Matthew
M.S. (Master of Science)
Department of Biological Sciences
Mycolaminaran, a β-1,3 glucan isolated from Phytophthora megasperma, induced strong resistance to TMV on N. tabacum cv. Xanthi-nc, N. glutinosa, and weak resistance on Pinto bean. The glucan induced no resistance on N. rustica nor on the progeny of the hybrid cross between N. rustica and N. tabacum. The response apparently was not an inactivation of the virus and was not inherited as a simple dominant trait. Mycolaminaran caused a reduction in the number of starch lesions formed on N. tabacum cv. Xanthi thereby establishing that the response was independent of the necrosis gene. Time course studies and its induced resistance to TMV RNA showed that the induced resistance was an immediate response, and one that blocked a step in replication at some point after the uncoating of the virus. The induced resistance was strictly a localized response. In addition to TMV, a single-stranded plus sense RNA virus, mycolaminaran induced resistance to CaMV, a double stranded DNA virus, on D. stramonium, and to TSWV, an enveloped ambisense virus, on N. glutinosa. These results support the hypothesis that the mechanism of mycolaminaran induced resistance was not limited to steps unique to replication of single-stranded RNA viruses. The mycolaminaran response was temperature sensitive, depending primarily on the pre-inoculation temperature and secondarily light conditions and the age of the leaf. When plants were kept at 30-32° C for 24-48 hr before inoculation mycolaminaran- induced resistance was reduced. At 30° C, the younger leaves of Xanthi-nc displayed mycolaminaran-induced resistance, but the older leaves did not.
Heinkel, Christina M., "Characterization of Mycolaminaran-induced resistance against plant viruses" (1992). Graduate Research Theses & Dissertations. 1742.
v, 62 pages
Northern Illinois University
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