Comparative RNA-seq analysis of nickel hyperaccumulating and non-accumulating populations of Senecio coronatus (Asteraceae)

Stuart K. Meier, Nicolette Adams, Michael Wolf, Kevin Balkwill, Abraham Muthama Muasya, Christoph A. Gehring, Jacqueline M. Bishop, Robert A. Ingle*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Most metal hyperaccumulating plants accumulate nickel, yet the molecular basis of Ni hyperaccumulation is not well understood. We chose Senecio coronatus to investigate this phenomenon as this species displays marked variation in shoot Ni content across ultramafic outcrops in the Barberton Greenstone Belt (South Africa), thus allowing an intraspecific comparative approach to be employed. No correlation between soil and shoot Ni contents was observed, suggesting that this variation has a genetic rather than environmental basis. This was confirmed by our observation that the accumulation phenotype of plants from two hyperaccumulator and two non-accumulator populations was maintained when the plants were grown on a soil mix from these four sites for 12 months. We analysed the genetic variation among 12 serpentine populations of S. coronatus, and used RNA-seq for de novo transcriptome assembly and analysis of gene expression in hyperaccumulator versus non-accumulator populations. Genetic analysis revealed the presence of hyperaccumulators in two well supported evolutionary lineages, indicating that Ni hyperaccumulation may have evolved more than once in this species. RNA-Seq analysis indicated that putative homologues of transporters associated with root iron uptake in plants are expressed at elevated levels in roots and shoots of hyperaccumulating populations of S. coronatus from both evolutionary lineages. We hypothesise that Ni hyperaccumulation in S. coronatus may have evolved through recruitment of these transporters, which play a role in the iron-deficiency response in other plant species.

Original languageEnglish (US)
Pages (from-to)1023-1038
Number of pages16
JournalPlant Journal
Volume95
Issue number6
DOIs
StatePublished - Sep 2018

Bibliographical note

Publisher Copyright:
© 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd

Keywords

  • IRT1
  • Senecio coronatus
  • hyperaccumulation
  • iron uptake
  • nickel
  • serpentine

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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