Overexpression of PIP2;5 Aquaporin Alleviates Effects of Low Root Temperature on Cell Hydraulic Conductivity and Growth in Arabidopsis

Plant Physiol. 2012 May;159(1):479-88. doi: 10.1104/pp.112.194506. Epub 2012 Mar 20.

Abstract

The effects of low root temperature on growth and root cell water transport were compared between wild-type Arabidopsis (Arabidopsis thaliana) and plants overexpressing plasma membrane intrinsic protein 1;4 (PIP1;4) and PIP2;5. Descending root temperature from 25°C to 10°C quickly reduced cell hydraulic conductivity (L(p)) in wild-type plants but did not affect L(p) in plants overexpressing PIP1;4 and PIP2;5. Similarly, when the roots of wild-type plants were exposed to 10°C for 1 d, L(p) was lower compared with 25°C. However, there was no effect of low root temperature on L(p) in PIP1;4- and PIP2;5-overexpressing plants after 1 d of treatment. When the roots were exposed to 10°C for 5 d, L(p) was reduced in wild-type plants and in plants overexpressing PIP1;4, whereas there was still no effect in PIP2;5-overexpressing plants. These results suggest that the gating mechanism in PIP1;4 may be more sensitive to prolonged low temperature compared with PIP2;5. The reduction of L(p) at 10°C in roots of wild-type plants was partly restored to the preexposure level by 5 mm Ca(NO(3))(2) and protein phosphatase inhibitors (75 nm okadaic acid or 1 μm Na(3)VO(4)), suggesting that aquaporin phosphorylation/dephosphorylation processes were involved in this response. The temperature sensitivity of cell water transport in roots was reflected by a reduction in shoot and root growth rates in the wild-type and PIP1;4-overexpressing plants exposed to 10°C root temperature for 5 d. However, low root temperature had no effect on growth in plants overexpressing PIP2;5. These results provide strong evidence for a link between growth at low root temperature and aquaporin-mediated root water transport in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aquaporins / genetics
  • Aquaporins / metabolism*
  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Biological Transport
  • Cell Membrane / genetics
  • Cell Membrane / metabolism
  • Cell Membrane Permeability
  • Cold Temperature*
  • Gene Expression Regulation, Plant
  • Genes, Plant
  • Mercuric Chloride / pharmacology
  • Plant Roots / genetics
  • Plant Roots / growth & development
  • Plant Roots / metabolism*
  • Plant Shoots / physiology
  • Stress, Physiological
  • Time Factors
  • Water / physiology

Substances

  • Aquaporins
  • Arabidopsis Proteins
  • plasma membrane intrinsic protein 2 Arabidopsis
  • Water
  • Mercuric Chloride