Trans-generational inheritance of herbivory-induced phenotypic changes in Brassica rapa

Authors: KELLENBERGER, ROMAN - University Of Zurich; DESURMONT, GAYLORD - European Biological Control Laboratory (EBCL); SCHLUETER, PHILIPP - University Of Zurich; SHIESTL, FLORIAN - University Of Zurich

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2018
Publication Date: 2/28/2018
Citation: Kellenberger, R., Desurmont, G., Schlueter, P., Shiestl, F. 2018. Trans-generational inheritance of herbivory-induced phenotypic changes in Brassica rapa. Scientific Reports. 8(1), article 3536. 10.1038/s41598-018-21880-2.
DOI: https://doi.org/10.1038/s41598-018-21880-2

Interpretive Summary: Damage by insects and other stresses can induce changes in plants, and such changes may carry on to the next generation(s). Here we studied trans-generational changes in the mustard plant Brassica rapa and the consequences of these changes for insect-plant interactions. After being damaged by two species of caterpillars (Pieris brassicae and Mamestra brassicae), some changes in B. rapa morphology and reproductive traits were still detectable two generations after insect damage while changes in plant odors disappeared the first generation after damage. The consequences of these trans-generational effects were negligible for pollinators and parasitoids (insects that parasitize the caterpillars) visiting B. rapa. The results indicate that some important plant traits can be affected by the environmental conditions of their immediate ancestors, while others are not. These results may provide a basis for developing sustainable methods to protect crops from insect pests.

Technical Abstract: Biotic stress can induce plastic changes in fitness-relevant plant traits. Recently, it has been shown that such changes can be transmitted to subsequent generations. However, the occurrence and extent of transmission across different types of traits is still unexplored. Here, we assessed the emergence and transmission of herbivory-induced changes in Brassica rapa and their impact on interactions with insects. We analyzed changes in morphology and reproductive traits as well as in flower and leaf volatile emission during two generations with leaf herbivory by Mamestra brassicae and Pieris brassicae and two subsequent generations without herbivory. Herbivory induced changes in all trait types, increasing attractiveness of the plants to the parasitoid wasp Cotesia glomerata and decreasing visitation by the pollinator Bombus terrestris, a potential trade-off. While changes in floral and leaf volatiles disappeared in the first generation after herbivory, some changes in morphology and reproductive traits were still measurable two generations after herbivory. However, neither parasitoids nor pollinators further discriminated between groups with different past treatments. Our results suggest that transmission of herbivore-induced changes occurs preferentially in resource-limited traits connected to plant growth and reproduction. The lack of alterations in plant-insect interactions was likely due to the transient nature of volatile changes.