The evolution of pyrrolizidine alkaloid diversity among and within Jacobaea species. Issue 2 (10th September 2020)

• Record Type: Journal Article
• Authors: Chen, Yangan; Mulder, Patrick P. J.; Schaap, Onno; Memelink, Johan; Klinkhamer, Peter G. L.; Vrieling, Klaas
• Is Part Of: Journal of systematics and evolution. Volume 60:Issue 2(2022)
• Page Start: 361
• Page End: 376
• Publication Date: 2020-09-10
• Subjects: ancestral state reconstruction -- hierarchical cluster analysis -- LC‐MS/MS -- phylogenetic signal -- principal component analysis -- secondary metabolite diversity; Plants -- China -- Classification -- Periodicals; Plants -- Classification -- Periodicals; 580.12
• DOI: 10.1111/jse.12671
• Languages: English
• ISSNs: 1674-4918

Abstract

Abstract: Plants produce many secondary metabolites showing considerable inter‐ and intraspecific diversity of concentration and composition as a strategy to cope with environmental stresses. The evolution of plant defenses against herbivores and pathogens can be unraveled by understanding the mechanisms underlying chemical diversity. Pyrrolizidine alkaloids are a class of secondary metabolites with high diversity. We performed a qualitative and quantitative analysis of 80 pyrrolizidine alkaloids with liquid chromatography‐tandem mass spectrometry of leaves from 17 Jacobaea species including one to three populations per species with 4–10 individuals per population grown under controlled conditions in a climate chamber. We observed large inter‐ and intraspecific variation in pyrrolizidine alkaloid concentration and composition, which were both species‐specific. Furthermore, we sequenced 11 plastid and three nuclear regions to reconstruct the phylogeny of the 17 Jacobaea species. Ancestral state reconstruction at the species level showed mainly random distributions of individual pyrrolizidine alkaloids. We found little evidence for phylogenetic signals, as nine out of 80 pyrrolizidine alkaloids showed a significant phylogenetic signal for Pagel's λ statistics only, whereas no significance was detected for Blomberg's K measure. We speculate that this high pyrrolizidine alkaloid diversity is the result of the upregulation and downregulation of specific pyrrolizidine alkaloids depending on ecological needs rather than gains and losses of particular pyrrolizidine alkaloid biosynthesis genes during evolution. Abstract : Jacobaea species showed large inter‐ and intraspecific variation in pyrrolizidine alkaloid concentration and composition, which were both species‐specific. The taxonomic relationships derived from pyrrolizidine alkaloid profiles of different Jacobaea species were inconsistent with their phylogenetic relationships based on molecular markers. The distribution of individual pyrrolizidine alkaloids on the phylogeny was random, showing little evidence for phylogenetic signals.