Validation of suitable genes for normalization of diurnal gene expression studies in Chenopodium quinoa

PLoS One. 2021 Mar 11;16(3):e0233821. doi: 10.1371/journal.pone.0233821. eCollection 2021.

Abstract

Quinoa depicts high nutritional quality and abiotic stress resistance, attracting strong interest in the last years. To unravel the function of candidate genes for agronomically relevant traits, studying their transcriptional activities by RT-qPCR is an important experimental approach. The accuracy of such experiments strongly depends on precise data normalization. To date, validation of potential candidate genes for normalization of diurnal expression studies has not been performed in C. quinoa. We selected eight candidate genes based on transcriptome data and literature survey, including conventionally used reference genes. We used three statistical algorithms (BestKeeper, geNorm and NormFinder) to test their stability and added further validation by a simulation-based strategy. We demonstrated that using different reference genes, including those top ranked by stability, causes significant differences among the resulting diurnal expression patterns. Our results show that isocitrate dehydrogenase enzyme (IDH-A) and polypyrimidine tract-binding protein (PTB) are suitable genes to normalize diurnal expression data of two different quinoa accessions. Moreover, we validated our reference genes by normalizing two known diurnally regulated genes, BTC1 and BBX19. The validated reference genes obtained in this study will improve the accuracy of RT-qPCR data normalization and facilitate gene expression studies in quinoa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Chenopodium quinoa / genetics*
  • Chenopodium quinoa / metabolism
  • Gene Expression Regulation, Plant*
  • Isocitrate Dehydrogenase / genetics
  • Isocitrate Dehydrogenase / metabolism
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Polypyrimidine Tract-Binding Protein / genetics
  • Polypyrimidine Tract-Binding Protein / metabolism
  • RNA, Plant / metabolism
  • Real-Time Polymerase Chain Reaction
  • Transcriptome

Substances

  • Plant Proteins
  • RNA, Plant
  • Polypyrimidine Tract-Binding Protein
  • Isocitrate Dehydrogenase

Grants and funding

This study was partially funded by the Competitive Research Grant of the King Abdullah University of Science and Technology, Saudi Arabia awarded to CJ (Grant number: OSR-2016-CRG5-2966-02). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study. The rest of the costs were covered internally by the institute budget of the Plant Breeding Institute, Kiel University. We acknowledge the financial support by State of Schleswig-Holstein, Germany within the funding program “Open Access Publikationsfonds”.