title: Cranberry Resistance to Dodder Parasitism: Induced Chemical Defenses and Behavior of a Parasitic Plant.
abstract: Parasitic plants are common in many ecosystems, where they can structure community interactions and cause major economic damage. For example, parasitic dodder (Cuscuta spp.) can cause up to 80-100 % yield loss in heavily infested cranberry (Vaccinium macrocarpon) patches. Despite their ecological and economic importance, remarkably little is known about how parasitic plants affect, or are affected by, host chemistry. To examine chemically-mediated interactions between dodder and its cranberry host, we conducted a greenhouse experiment asking whether: (1) dodder performance varies with cranberry cultivar; (2) cultivars differ in levels of phytohormones, volatiles, or phenolics, and whether such variation correlates with dodder parasitism; (3) dodder parasitism induced changes in phytohormones, volatiles, or phenolics, and whether the level of inducible response varied among cultivars. We used five cranberry cultivars to assess host attractiveness to dodder and dodder performance. Dodder performance did not differ across cultivars, but there were marginally significant differences in host attractiveness to dodder, with fewer dodder attaching to Early Black than to any other cultivar. Dodder parasitism induced higher levels of salicylic acid (SA) across cultivars. Cultivars differed in overall levels of flavonols and volatile profiles, but not phenolic acids or proanthocyanidins, and dodder attachment induced changes in several flavonols and volatiles. While cultivars differed slightly in resistance to dodder attachment, we did not find evidence of chemical defenses that mediate these interactions. However, induction of several defenses indicates that parasitism alters traits that could influence subsequent interactions with other species, thus shaping community dynamics.
authors.affiliation: Biology Department, University of Massachusetts Amherst, 221 Morrill Science Center South, 611 North Pleasant Street, Amherst, MA, 01003, USA. connie.muv@gmail.com.
authors.forename: Muvari Connie
authors.initials: MC
authors.lastname: Tjiurutue
authors.affiliation: UMass Cranberry Experiment Station, 1 State Bog Rd, P.O Box 569, East Wareham, MA, 02538, USA.
authors.forename: Hilary A
authors.initials: HA
authors.lastname: Sandler
authors.affiliation: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA.|Departamento de Biologia Animal (IB), Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, SP, CEP 13083-970, Brasil.
authors.forename: Monica F
authors.initials: MF
authors.lastname: Kersch-Becker
authors.affiliation: Department of Biological Sciences, Elms College, 203 Berchmans Hall, Chicopee, MA, 01013, USA.
authors.forename: Nina
authors.initials: N
authors.lastname: Theis
authors.affiliation: Biology Department, University of Massachusetts Amherst, 221 Morrill Science Center South, 611 North Pleasant Street, Amherst, MA, 01003, USA.
authors.forename: Lynn A
authors.initials: LA
authors.lastname: Adler
mesh_terms: D034182:Cuscuta / Q000502:physiology*; D010636:Phenols / Q000378:metabolism; D010937:Plant Growth Regulators / Q000502:physiology; D018515:Plant Leaves / Q000378:metabolism; D029799:Vaccinium macrocarpon / Q000378:metabolism / Q000469:parasitology* / Q000502:physiology
chemical_list: D010636:Phenols; D010937:Plant Growth Regulators
keywords: Flavonols; Induced responses; Parasitism; Phytohormones; Plant-plant interactions; Volatiles