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Ecology and Epidemiology

Effects of Infection by Peanut Mottle Virus on Nodule Function. S. Wongkaew, Department of Plant Science, Macdonald College of McGill University, Ste. Anne de Bellevue, Quebec H9X 1C0, Present address of senior author: Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand; J. F. Peterson, Department of Plant Science, Macdonald College of McGill University, Ste. Anne de Bellevue, Quebec H9X 1C0. Phytopathology 76:294-300. Accepted for publication 2 October 1985. Copyright 1986 Department of Agriculture, Government of Canada. DOI: 10.1094/Phyto-76-294.

The effects of infection by peanut mottle virus on nodulation and nodule function of cultivar Early Prolific peanuts, inoculated with either effective or ineffective strains of Rhizobium and grown under controlled conditions, were assessed at the early blooming, late blooming, pegging, and pod-filling stages. Virus-infected plants showed differences in magnitude of growth reduction and nodulation pattern, depending on whether they harbored the effective or ineffective rhizobial strain. In plants infected with effective rhizobia, the commencing of nitrogenase activity (estimated by measuring C₂H₂ reduction) was delayed, and the activity measured on a per plant basis was reduced, but the maximum nodular specific activity per milligram of nodule tissue was not significantly lower than that of healthy plants. There was no correlation between leghemoglobin content and the nitrogenase-specific activity of nodules from plants infected with peanut mottle virus, but a positive correlation was observed in the healthy controls. Assays indicated the presence of infective peanut mottle virus in tissues of both effective and ineffective nodules.