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Trading direct for indirect defense? Phytochrome B inactivation in tomato attenuates direct anti‐herbivore defenses whilst enhancing volatile‐mediated attraction of predators
Author(s) -
Cortés Leandro E.,
Weldegergis Berhane T.,
Boccalandro Hernán E.,
Dicke Marcel,
Ballaré Carlos L.
Publication year - 2016
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14210
Subject(s) - herbivore , attraction , predation , solanum , biology , competition (biology) , predator , methyl jasmonate , plant defense against herbivory , jasmonate , botany , ecology , gene , arabidopsis , genetics , linguistics , philosophy , mutant
Summary Under conditions of competition for light, which lead to the inactivation of the photoreceptor phytochrome B (phyB), the growth of shade‐intolerant plants is promoted and the accumulation of direct anti‐herbivore defenses is down‐regulated. Little is known about the effects of phyB on emissions of volatile organic compounds (VOCs), which play a major role as informational cues in indirect defense. We investigated the effects of phyB on direct and indirect defenses in tomato ( Solanum lycopersicum ) using two complementary approaches to inactivate phyB: illumination with a low red to far‐red ratio, simulating competition, and mutation of the two PHYB genes present in the tomato genome. Inactivation of phyB resulted in low levels of constitutive defenses and down‐regulation of direct defenses induced by methyl jasmonate (MeJA). Interestingly, phyB inactivation also had large effects on the blends of VOCs induced by MeJA. Moreover, in two‐choice bioassays using MeJA‐induced plants, the predatory mirid bug Macrolophus pygmaeus preferred VOCs from plants in which phyB was inactivated over VOCs from control plants. These results suggest that, in addition to repressing direct defense, phyB inactivation has consequences for VOC‐mediated tritrophic interactions in canopies, presumably attracting predators to less defended plants, where they are likely to find more abundant prey.