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Oral: Contributions of Plant Viruses to Phytobiome Research


Characterization of diverse virus populations associated with plant-pathogenic nematodes.
S. BEKAL (1), K. Lambert (1), G. Tylka (2), K. Bhalerao (1) (1) University of Illinois, U.S.A.; (2) Iowa State University, U.S.A.

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Viruses have not been used for nematode control because few nematode infecting viruses have been identified. Recently, five viruses were discovered that infect Heterodera glycines, the soybean cyst nematode (SCN). Our objectives were to identify mechanisms of virus transmission, to assess virus prevalence in natural SCN populations and to estimate virus-mediated damage to infected nematodes. Viruses were detected in SCN populations using quantitative reverse transcription PCR. All developmental stages of SCN were tested and found to contain viruses, suggesting that viruses are transmitted vertically or via male SCN during mating. Surprisingly, virus-infected SCN appear to have increased motility as compared to uninfected SCN. While one laboratory culture of SCN contained all known SCN viruses, most field SCN populations harbored only one or two viruses. The frequency of field SCN populations containing viruses varied by location, but viral incidence was up to 100 % at some field sites. By monitoring multiple generations of virus-infected SCN, specific viruses appeared to be suppressed in the nematode generation after the virus titer reached a high level. The reduction of specific virus levels may be due to virus-mediated damage to the eggs, preventing their hatching and lowering the virus titer in the next nematode generation. The observation that nematode viruses may damage SCN eggs suggests that SCN viruses may be exploited as biological control agents of SCN.