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Strigolactones and gibberellic acid regulate aphid fecundity in pea
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  • Hendrik Swiegers,
  • Barbara Karpinska,
  • Yan Hu,
  • Ian Dodd,
  • Anna-Maria Botha,
  • Christine Foyer
Hendrik Swiegers
University of Birmingham Edgbaston Campus
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Barbara Karpinska
University of Birmingham
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Yan Hu
Zhejiang University
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Ian Dodd
University of Lancaster
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Anna-Maria Botha
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Christine Foyer
University of Birmingham
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Abstract

Atmospheric CO2 levels influences plant growth and susceptibility to pathogens and pests but there is little information on the mechanisms involved. We therefore studied how elevated atmospheric CO2 concentrations (eCO2) effects shoot branching and the performance of the pea aphid on wild type peas and on mutants that are defective in either strigolactone (SL) synthesis or signalling. Shoot branching and dry biomass accumulation were increased under eCO2 conditions in all lines. However, eCO2 decreased shoot water content only in the wild type peas but not in the SL mutants. Growth under eCO2 decreased the levels of salicylic acid and increased jasmonic acid in the wild type peas, without any significant effect on aphid fecundity. However, aphid numbers were increased on the SL mutants under both ambient and eCO2 conditions. Of the shoot phytohormones measured in this study, only gibberellic acid (GA3) was decreased in the SL mutants, an effect that was exacerbated by eCO2. There was a negative correlation between aphid fecundity and shoot GA3 levels. Taken together, these studies provide confirm that eCO2 modifies the levels of defence hormones and provides the first evidence that SL and GA3 are important regulators of plant responses to phloem-feeding insects.

Peer review status:UNDER REVIEW

19 Aug 2020Submitted to Plant, Cell & Environment
20 Aug 2020Assigned to Editor
20 Aug 2020Submission Checks Completed
31 Aug 2020Review(s) Completed, Editorial Evaluation Pending