title: Soybean resistance to stink bugs (Nezara viridula and Piezodorus guildinii) increases with exposure to solar UV-B radiation and correlates with isoflavonoid content in pods under field conditions.
abstract: Solar UV-B radiation (280-315 nm) has a significant influence on trophic relationships in natural and managed ecosystems, affecting plant-insect interactions. We explored the effects of ambient UV-B radiation on the levels of herbivory by stink bugs (Nezara viridula and Piezodorus guildinii) in field-grown soybean crops. The experiments included two levels of UV-B radiation (ambient and attenuated UV-B) and four soybean cultivars known to differ in their content of soluble leaf phenolics. Ambient UV-B radiation increased the accumulation of the isoflavonoids daidzin and genistin in the pods of all cultivars. Soybean crops grown under attenuated UV-B had higher numbers of unfilled pods and damaged seeds than crops grown under ambient UV-B radiation. Binary choice experiments with soybean branches demonstrated that stink bugs preferred branches of the attenuated UV-B treatment. We found a positive correlation between percentage of undamaged seeds and the contents of daidzin and genistin in pods. Our results suggest that constitutive and UV-B-induced isoflavonoids increase plant resistance to stink bugs under field conditions.
authors.affiliation: Cátedra de Bioquímica, Facultad de Agronomía, Universidad de Buenos Aires, C1417DSE, Buenos Aires, Argentina; INBA, Universidad de Buenos Aires, C1417DSE, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ, Buenos Aires, Argentina.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Zavala
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Mazza
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Dillon
authors.forename: Hugo D
authors.initials: HD
authors.lastname: Chludil
authors.forename: Carlos L
authors.initials: CL
authors.lastname: Ballaré
mesh_terms: D000818:Animals; D005638:Fruit / Q000378:metabolism; D019833:Genistein / Q000378:metabolism*; D060434:Herbivory; D020062:Heteroptera; D007529:Isoflavones / Q000378:metabolism*; D013025:Glycine max / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D007529:Isoflavones; C004742:daidzein; D019833:Genistein
keywords: daidzin; genistin; isoflavonoids; plant-insect interactions; pod feeders