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  • Publication
    Accès libre
    Experimental Growth Conditions affect Direct and Indirect Defences in two Cotton Species
    (2023)
    Laura Chappuis
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    Alicia Egger
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    ; ; ; ;
    Luis Abdala-Roberts
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    Mary V. Clancy
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    ;
    Cotton has been used as a model plant to study direct and indirect plant defence against herbivorous insects. However, the plant growing conditions could have an important effect on the outcome of such plant defence studies. We examined how common experimental growth conditions influence constitutive and inducible defences in two species of cotton, Gossypium hirsutum and G. herbaceum. We induced plants by applying caterpillar regurgitant to mechanical wounds to compare the induction levels between plants of both species grown in greenhouse or phytotron conditions. For this we measured defence metabolites (gossypol and heliocides) and performance of Spodoptera frugiperda caterpillars on different leaves, the emission of plant volatiles, and their attractiveness to parasitic wasps. Induction increased the levels of defence metabolites, which in turn decreased the performance of S. frugiperda larvae. Constitutive and induced defence levels were the highest in plants grown in the phytotron (compared to greenhouse plants), G. hirsutum and young leaves. Defence induction was more pronounced in plants grown in the phytotron and in young leaves. Also, the differences between growing conditions were more evident for metabolites in the youngest leaves, indicating an interaction with plant ontogeny. The composition of emitted volatiles was different between plants from the two growth conditions, with greenhouse-grown plants showing more variation than phytotron-grown plants. Also, G. hirsutum released higher amounts of volatiles and attracted more parasitic wasps than G. herbaceum. Overall, these results highlight the importance of experimental abiotic factors in plant defence induction and ontogeny of defences. We therefore suggest careful consideration in selecting the appropriate experimental growing conditions for studies on plant defences.
  • Publication
    Accès libre
    A receptor-like protein mediates plant immune responses to herbivore-associated molecular patterns
    (2020-11-23)
    Steinbrenner, Adam D.
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    Muñoz-Amatriaín, Maria
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    Chaparro, Antonio F.
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    Aguilar-Venegas, Jessica Montserrat
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    Lo, Sassoum
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    Okuda, Satohiro
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    Dongiovanni, Julien
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    Shi, Da
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    Hall, Marlo
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    Crubaugh, Daniel
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    Holton, Nicholas
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    Zipfel, Cyril
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    Abagyan, Ruben
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    Close, Timothy J.
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    Huffaker, Alisa
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    Schmelz, Eric A.
    Herbivory is fundamental to the regulation of both global food webs and the extent of agricultural crop losses. Induced plant responses to herbivores promote resistance and often involve the perception of specific herbivore-associated molecular patterns (HAMPs); however, precisely defined receptors and elicitors associated with herbivore recognition remain elusive. Here, we show that a receptor confers signaling and defense outputs in response to a defined HAMP common in caterpillar oral secretions (OS). Staple food crops, including cowpea (Vigna unguiculata) and common bean (Phaseolus vulgaris), specifically respond to OS via recognition of proteolytic fragments of chloroplastic ATP synthase, termed inceptins. Using forward-genetic mapping of inceptin-induced plant responses, we identified a corresponding leucine-rich repeat recep-tor, termed INR, specific to select legume species and sufficient to confer inceptin-induced responses and enhanced defense against armyworms (Spodoptera exigua) in tobacco. Our results support the role of plant immune receptors in the perception of chewing herbivores and defense.