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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #336937
Title: Potato stem cuttings to study Verticillium dahliae infection for resistance breeding and 'omics' studies

Author
item KUMAR, ARUN - University Of Wisconsin
item Jansky, Shelley
item Halterman, Dennis

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2017
Publication Date: 1/27/2017
Citation: Kumar, A., Jansky, S.H., Halterman, D.A. 2017. Potato stem cuttings to study Verticillium dahliae infection for resistance breeding and 'omics' studies. American Journal of Potato Research. 94(3):270-274. https://doi.org/10.1007/s12230-016-9563-z.
DOI: https://doi.org/10.1007/s12230-016-9563-z

Interpretive Summary: In this paper, we describe a new method of inoculating and screening potato plants for resistance or susceptibility to the fungus Verticillium dahliae (Vd), the causal agent of Verticillium wilt (VW). Previous methods are not reliable because escapes are common in field assays and it is difficult to identify differences between resistant plants and those that are susceptible but show no symptoms. As an alternative strategy, we have developed a protocol for studying infection of Vd using potato stem cuttings. The protocol was validated using plants varying in resistance/susceptibility to Vd. Although there were no visual symptoms in the plants, stem sections were found to be infested with Vd as early as 7 days post inoculation (dpi). Symptoms were first observed in the most susceptible plants at 10 dpi and became apparent on all test subjects at 14 dpi. The protocol has potential applications in resistance breeding and studies where populations derived from true seeds are not available.

Technical Abstract: Consistent and effective methods for early discrimination of pathogen resistance, and selection of times for tissue sampling, are important for experiments using global gene expression and metabolomics. Assays for resistance to the vascular pathogen Verticillium dahliae (Vd), the causal agent of Verticillium wilt (VW), are particularly difficult because escapes are common in field assays. Seedling dip assays offer a potential solution, but homogeneous populations are not typically available. As an alternative strategy, we have developed a protocol for studying spatiotemporal infection dynamics of Vd using potato stem cuttings. The protocol was validated using genotypes varying in resistance/susceptibility to Vd. Although there were no visual symptoms in the plants, stem sections were infested with Vd as early as 7 dpi. Symptoms were first observed in the most susceptible genotype at 10 dpi and became apparent on all test subjects at 14 dpi. The protocol has potential applications in resistance breeding and ‘omics’ studies where populations derived from true seeds are not available.