AtEXP2 is involved in seed germination and abiotic stress response in Arabidopsis

PLoS One. 2014 Jan 3;9(1):e85208. doi: 10.1371/journal.pone.0085208. eCollection 2014.

Abstract

Expansins are cell wall proteins that promote cell wall loosening by inducing pH-dependent cell wall extension and stress relaxation. Expansins are required in a series of physiological developmental processes in higher plants such as seed germination. Here we identified an Arabidopsis expansin gene AtEXPA2 that is exclusively expressed in germinating seeds and the mutant shows delayed germination, suggesting that AtEXP2 is involved in controlling seed germination. Exogenous GA application increased the expression level of AtEXP2 during seed germination, while ABA application had no effect on AtEXP2 expression. Furthermore, the analysis of DELLA mutants show that RGL1, RGL2, RGA, GAI are all involved in repressing AtEXP2 expression, and RGL1 plays the most dominant role in controlling AtEXP2 expression. In stress response, exp2 mutant shows higher sensitivity than wild type in seed germination, while overexpression lines of AtEXP2 are less sensitive to salt stress and osmotic stress, exhibiting enhanced tolerance to stress treatment. Collectively, our results suggest that AtEXP2 is involved in the GA-mediated seed germination and confers salt stress and osmotic stress tolerance in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Gene Expression Regulation, Plant
  • Germination / genetics*
  • Osmotic Pressure
  • Phenotype
  • Plant Proteins / genetics*
  • Plants, Genetically Modified
  • Salt Tolerance / genetics
  • Seeds / genetics*
  • Seeds / metabolism*
  • Stress, Physiological* / genetics

Substances

  • Arabidopsis Proteins
  • Plant Proteins
  • expansin protein, plant

Grants and funding

The research was supported by International Scientific and Technological Cooperation Project of Science and Technology Department of Zhejiang Province (grant number 2013C34G2010017), the International Scientific and Technological Cooperation Project of the Ministry of Science and Technology of China (grant number 2010DFA34430), National Natural Science Foundation of China (Grant No. 31370215; 31228002), and Zhejiang Provincial Natural Science Foundation of China (Grant No. Z31100041). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.