Phytochemical Shift from Condensed Tannins to Flavonoids in Transgenic Betula pendula Decreases Consumption and Growth but Improves Growth Efficiency of Epirrita autumnata Larvae

• DOI: 10.1007/s10886-019-01134-9
• Publication Date: 2019-12-26T07:02:50Z
• Authors: Paula Thitz; Lauri Mehtätalo; Panu Välimäki; Tendry Randriamanana; Mika Lännenpää; Ann E. Hagerman; Tommi Andersson; Riitta Julkunen-T...; Tommi Nyman
• Keywords: Betula pendula; Tannin; Secondary metabolism; Anthocyanidins; Condensed tannin

Abstract Despite active research, antiherbivore activity of specific plant phenolics remains largely unresolved. We constructed silver birch ( Betula pendula ) lines with modified phenolic metabolism to study the effects foliar flavonoids and condensed tannins on consumption growth larvae a generalist herbivore, autumnal moth Epirrita autumnata ). conducted feeding experiment using in which expression dihydroflavonol reductase DFR ), anthocyanidin synthase ANS or ANR had been decreased by RNA interference. Modification-specific phenolics, nutrients phenotype, larval were analyzed uni- multivariate methods. Inhibiting increased concentration at expense tannins, silencing leaf size. E. consumed average 82% less DFRi plants than unmodified controls, suggesting that glandular trichomes deter feeding. However, efficiency was highest low-tannin plants, indicating (or their monomers) are physiologically more harmful non-tannin for larvae. Our results show genetic manipulation flavonoid pathway can effectively be used produce altered profiles required elucidating roles low-molecular weight plant–herbivore relationships, suggest secondary metabolites participate regulation growth.