Genome‐material costs and functional trade‐offs in the autopolyploid Solidago gigantea (giant goldenrod) series

Abstract

Premise of studyIncreased genomic “material costs” of nitrogen (N) and phosphorus (P) atoms inherent to organisms with larger genome sizes (GS) has been proposed to limit growth under nutrient scarcities and promote growth under nutrient enrichments. Such responsiveness may reflect a nutrient‐dependent diploid versus polyploid advantage that could have vast ecological and evolutionary implications, but direct evidence that material costs increase with ploidy‐level and/or influence cytotype‐dependent growth, metabolic, and/or resource‐use tradeoffs is limited.MethodsWe grew diploid, auto‐tetraploid, and auto‐hexaploid Solidago gigantea plants under one of four ambient and enriched N:P treatments and measured traits related to material costs, primary and secondary metabolism, and resource‐use.Key resultsRelative to diploids, polyploids invested more N and P into cells and tetraploids grew more following N‐enrichments, suggesting that material costs increase with ploidy‐level. Polyploids also generally exhibited strategies that could minimize material‐cost‐constraints over both long (reduced monoploid GS) and short (more extreme transcriptome downsizing, reduced photosynthesis rates and terpene concentrations, enhanced N‐use efficiencies) evolutionary time periods. Furthermore, polyploids had lower transpiration rates but higher water‐use‐efficiencies than diploids, both of which were more pronounced under nutrient‐limiting conditions.ConclusionsCollectively we found that NP material costs increase with ploidy‐level but that material‐cost‐constraints might be lessened by organismal resource allocation/investment mechanisms that can also alter ecological dynamics and selection. Our results enhance mechanistic understanding of how global increases in nutrients might provide a release from material‐cost‐constraints in polyploids that could impact ploidy (or GS)‐specific performances, cytogeographic patterning, and multispecies community structuring.This article is protected by copyright. All rights reserved.