DOI: 10.5061/dryad.687m14t
title: Data from: Macroevolutionary patterns in overexpression of tyrosine: an anti-herbivore defense in a speciose tropical tree genus, Inga (Fabaceae)

description: Plant secondary metabolites are a key defence against herbivores, and
 their evolutionary origin is likely from primary metabolites. Yet for this
 to occur, an intermediate step of overexpression of primary metabolites
 would need to confer some advantage to the plant. Here, we examine the
 evolution of overexpression of the essential amino acid, L‐tyrosine and
 its role as a defence against herbivores. We examined overexpression of
 tyrosine in 97 species of Inga (Fabaceae), a genus of tropical trees, at
 five sites throughout the Neotropics. We predicted that tyrosine could act
 as an anti‐herbivore defence because concentrations of 4% tyrosine in
 artificial diets halved larval growth rates. We also collected insect
 herbivores to determine if tyrosine and its derivatives influenced host
 associations. Overexpression of tyrosine was only present in a single
 lineage comprising 21 species, with concentrations ranging from 5% to 20%
 of the leaf dry weight. Overexpression was pronounced in expanding but not
 in mature leaves. Despite laboratory studies showing toxicity of
 L‐tyrosine, Inga species with tyrosine suffered higher levels of
 herbivory. We therefore hypothesize that overexpression is only favoured
 in species with less effective secondary metabolites. Some
 tyrosine‐producing species also contained secondary metabolites that are
 derived from tyrosine: tyrosine‐gallates, tyramine‐gallates and
 DOPA‐gallates. Elevated levels of transcripts of prephenate dehydrogenase,
 an enzyme in the tyrosine biosynthetic pathway that is insensitive to
 negative feedback from tyrosine, were found only in species that
 overexpress tyrosine or related gallates. Different lineages of herbivores
 showed contrasting responses to the overexpression of tyrosine and its
 derived secondary metabolites in their host plants. Synthesis. We propose
 that overexpression of some primary metabolites can serve as a chemical
 defence against herbivores, and are most likely to be selected for in
 species suffering high herbivory due to less effective secondary
 metabolites. Overexpression may be the first evolutionary step in the
 transition to the production of more derived secondary metabolites.
 Presumably, derived compounds would be more effective and less costly than
 free tyrosine as anti‐herbivore defences.
description: Retention time and
 abundance of tyrosine and derivatives in IngaTyrosine content and the
 retention times and abundances of tyrosine, tyramine and DOPA gallate ions
 for each species and site. The ‘Species code’ is our identifier for both
 species and site. Codes beginning in 'Ing' are from Barro
 Colorado Island, Panama; 'LA' are from Los Amigos, Peru,
 'M' are from Manaus (Km41), Brazil; 'N' are from
 Nouragues, French Guiana; and 'T' are from Tiputini, Ecuador.
 Exp and M are expanding and mature leaves, respectively, with ‘n’
 indicating sample size. RT is retention time on the UPLC column. TIC is
 total ion count or ion abundance. Most species/site combinations had five
 independent UPLC-MS analyses; the exceptions are noted. All UPLC-MS
 analyses were as described in ‘Analysis of gallic acid depsides of
 tyrosine, tyramine and DOPA’. For this table, one sample with the highest
 signal was analyzed per species/site combination by searching for the m/z
 values given in Table S2. Since the ion abundances of these amines were
 consistently higher by factors of 6x to 60x for positive mode relative to
 negative mode, this analysis exclusively used positive mode data in order
 to maximize sensitivity.Table-S4.xlsTranscriptomic data for Inga speciesQuality metrics for transcriptomes. Quantity and quality of RNA, library size, Trinity assembly metrics and the percentage of contigs annotated through the Trinnotate pipeline.Table-S5.csvRecorded damage to Inga by insect herbivores separated by site and tyrosine expressionHerbivore damage to expanding leaves for species with and without tyrosine overexpression. Species that contained tyrosine-derivatives in addition to free tyrosine were included in the tyrosine-plus category. Data are from French Guiana (FG), Brazil (B), Peru (Pe) and Ecuador (E). Panama is excluded from the analysis as only one species contained tyrosine. An ANOVA exploring the effect of tyrosine status (T+ or T-) on herbivory showed lower damage for species without tyrosine (p &lt; 0.001).Figure-3.pdfAssembled transcriptomesTrinity assemblies of Inga transcriptomesInga_Trinity_assembelies.tar.gzSalmon counts with I_sapindoides as referenceSalmon counts for each transcriptome. Generated using I. sapindoides BCI-97 as the reference transcriptomeTo_sap_97_Salmon.tar.gzAnnotation of Inga transcriptomesTrinnotate annotation for transcriptomes assembled from RNASeq of wild collected expanding leavestrinnnotates.tar.gz