Transcriptome-Wide Identification and Expression Analysis of the NAC Gene Family in Tea Plant [Camellia sinensis (L.) O. Kuntze]

PLoS One. 2016 Nov 17;11(11):e0166727. doi: 10.1371/journal.pone.0166727. eCollection 2016.

Abstract

In plants, the NAC (NAM-ATAF1/2-CUC) family of proteins constitutes several transcription factors and plays vital roles in diverse biological processes, such as growth, development, and adaption to adverse factors. Tea, as a non-alcoholic drink, is known for its bioactive ingredients and health efficacy. Currently, knowledge about NAC gene family in tea plant remains very limited. In this study, a total of 45 CsNAC genes encoding NAC proteins including three membrane-bound members were identified in tea plant through transcriptome analysis. CsNAC factors and Arabidopsis counterparts were clustered into 17 subgroups after phylogenetic analysis. Conserved motif analysis revealed that CsNAC proteins with a close evolutionary relationship possessed uniform or similar motif compositions. The distribution of NAC family MTFs (membrane-associated transcription factors) among higher plants of whose genome-wide has been completed revealed that the existence of doubled TMs (transmembrane motifs) may be specific to fabids. Transcriptome analysis exhibited the expression profiles of CsNAC genes in different tea plant cultivars under non-stress conditions. Nine CsNAC genes, including the predicted stress-related and membrane-bound genes, were examined through qRT-PCR (quantitative real time polymerase chain reaction) in two tea plant cultivars, namely, 'Huangjinya' and 'Yingshuang'. The expression patterns of these genes were investigated in different tissues (root, stem, mature leaf, young leaf and bud) and under diverse environmental stresses (drought, salt, heat, cold and abscisic acid). Several CsNAC genes, including CsNAC17 and CsNAC30 that are highly orthologous to known stress-responsive ANAC072/RD26 were identified as highly responsive to abiotic stress. This study provides a global survey of tea plant NAC proteins, and would be helpful for the improvement of stress resistance in tea plant via genetic engineering.

MeSH terms

  • Abscisic Acid / pharmacology
  • Amino Acid Sequence
  • Arabidopsis / genetics
  • Camellia sinensis / drug effects
  • Camellia sinensis / genetics*
  • Camellia sinensis / physiology
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cluster Analysis
  • Conserved Sequence / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant* / drug effects
  • Genes, Plant*
  • Multigene Family*
  • Nucleotide Motifs
  • Organ Specificity / drug effects
  • Organ Specificity / genetics
  • Phylogeny
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Real-Time Polymerase Chain Reaction
  • Sequence Alignment
  • Stress, Physiological / drug effects
  • Stress, Physiological / genetics
  • Temperature
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcriptome / drug effects
  • Transcriptome / genetics*

Substances

  • Plant Proteins
  • Transcription Factors
  • Abscisic Acid

Grants and funding

The research was supported by the National Natural Science Foundation of China (31570691). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.