Butterfly eggs prime anti-herbivore defense in an annual but not perennialArabidopsisspecies

Abstract

AbstractWhile plant anti-herbivore defenses of the annual plant speciesArabidopsis thalianawere shown to be primable byPieris brassicaeeggs, the primability of the phylogenetically closely related perennialArabidopsis lyratahas not yet been investigated. Previous studies revealed that closely related wild Brassicaceae plant species, the annualBrassica nigraand the perennialBrassica oleracea, exhibit an egg-primable defense trait, even though they have different life spans. Here, we tested whetherP. brassicaeeggs prime anti-herbivore defenses of the perennialA. lyrata. We exposedA. lyratatoP. brassicaeeggs and larval feeding and assessed their primability by i) determining the biomass ofP. brassicaelarvae after feeding on plants with and without priorP. brassicaeegg deposition and ii) investigating the plant transcriptomic response after egg deposition and/or larval feeding. For comparison, these studies were also conducted withA. thaliana.Consistent with previous findings,A. thaliana’s response to priorP. brassicaeegg deposition negatively affected conspecific larvae feeding uponA. thaliana. However, this was not observed inA. lyrata.Arabidopsis thalianaresponded toP. brassicaeeggs with strong transcriptional reprogramming, whereasA. lyrataresponses to eggs were negligible. In response to larval feeding,A. lyrataexhibited a greater transcriptome change compared toA. thaliana. Among the strongly feeding-inducedA. lyratagenes were those that are egg-primed in feeding-inducedA. thaliana, i.e.,CAX3, PR1,PR5andPDF1.4.These results suggest thatA. lyratacompensates for its lack of egg-mediated primability by a stronger response to larval feeding.