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Leaf rust infection reduces herbivore‐induced volatile emission in black poplar and attracts a generalist herbivore
Author(s) -
Eberl Franziska,
Hammerbacher Almuth,
Gershenzon Jonathan,
Unsicker Sybille B.
Publication year - 2018
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.14565
Subject(s) - herbivore , biology , plant defense against herbivory , plant tolerance to herbivory , botany , lymantria dispar , fungus , rust (programming language) , green leaf volatiles , lepidoptera genitalia , generalist and specialist species , ecology , biochemistry , computer science , gene , programming language , habitat
Summary Plants release complex volatile blends after separate attack by herbivores and pathogens, which play many roles in interactions with other organisms. Large perennials are often attacked by multiple enemies, but the effect of combined attacks on volatile emission is rarely studied, particularly in trees. We infested Populus nigra trees with a pathogen, the rust fungus Melampsora larici‐populina , and Lymantria dispar caterpillars alone and in combination. We investigated poplar volatile emission and its regulation, as well as the behavior of the caterpillars towards volatiles from rust‐infected and uninfected trees. Both the rust fungus and the caterpillars alone induced volatile emission from poplar trees. However, the herbivore‐induced volatile emission was significantly reduced when trees were under combined attack by the herbivore and the fungus. Herbivory induced terpene synthase transcripts as well as jasmonate concentrations, but these increases were suppressed when the tree was additionally infected with rust. Caterpillars preferred volatiles from rust‐infected over uninfected trees. Our results suggest a defense hormone crosstalk upon combined herbivore–pathogen attack in poplar trees which results in lowered emission of herbivore‐induced volatiles. This influences the preference of herbivores, and might have other far‐reaching consequences for the insect and pathogen communities in natural poplar forests.