Chilling- and Freezing-Induced Alterations in Cytosine Methylation and Its Association with the Cold Tolerance of an Alpine Subnival Plant, Chorispora bungeana

PLoS One. 2015 Aug 13;10(8):e0135485. doi: 10.1371/journal.pone.0135485. eCollection 2015.

Abstract

Chilling (0-18°C) and freezing (<0°C) are two distinct types of cold stresses. Epigenetic regulation can play an important role in plant adaptation to abiotic stresses. However, it is not yet clear whether and how epigenetic modification (i.e., DNA methylation) mediates the adaptation to cold stresses in nature (e.g., in alpine regions). Especially, whether the adaptation to chilling and freezing is involved in differential epigenetic regulations in plants is largely unknown. Chorispora bungeana is an alpine subnival plant that is distributed in the freeze-thaw tundra in Asia, where chilling and freezing frequently fluctuate daily (24 h). To disentangle how C. bungeana copes with these intricate cold stresses through epigenetic modifications, plants of C. bungeana were treated at 4°C (chilling) and -4°C (freezing) over five periods of time (0-24 h). Methylation-sensitive amplified fragment-length polymorphism markers were used to investigate the variation in DNA methylation of C. bungeana in response to chilling and freezing. It was found that the alterations in DNA methylation of C. bungeana largely occurred over the period of chilling and freezing. Moreover, chilling and freezing appeared to gradually induce distinct DNA methylation variations, as the treatment went on (e.g., after 12 h). Forty-three cold-induced polymorphic fragments were randomly selected and further analyzed, and three of the cloned fragments were homologous to genes encoding alcohol dehydrogenase, UDP-glucosyltransferase and polygalacturonase-inhibiting protein. These candidate genes verified the existence of different expressive patterns between chilling and freezing. Our results showed that C. bungeana responded to cold stresses rapidly through the alterations of DNA methylation, and that chilling and freezing induced different DNA methylation changes. Therefore, we conclude that epigenetic modifications can potentially serve as a rapid and flexible mechanism for C. bungeana to adapt to the intricate cold stresses in the alpine areas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acclimatization
  • Amplified Fragment Length Polymorphism Analysis / methods
  • Asia
  • Brassicaceae / genetics*
  • Brassicaceae / growth & development
  • Cytosine / metabolism*
  • DNA Methylation*
  • DNA, Plant / analysis
  • Epigenesis, Genetic
  • Gene Expression Regulation, Plant
  • Plant Proteins / genetics*

Substances

  • DNA, Plant
  • Plant Proteins
  • Cytosine

Grants and funding

This research was supported by the National Basic Research Program of China (973 Program) (2014CB954203); The National Natural Science Foundation of China (No. 31200298); The Key Program National Natural Science Foundation of China (No. 31230014); The Fundamental Research Funds for the Central Universities (lzujbky-2014-99 and lzujbky-2014-bt05). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.