title: MIZ1-regulated hydrotropism functions in the growth and survival of Arabidopsis thaliana under natural conditions.
abstract: OBJECTIVE
  Root hydrotropism is a response to water-potential gradients that makes roots bend towards areas of higher water potential. The gene MIZU-KUSSEI1 (MIZ1) that is essential for hydrotropism in Arabidopsis roots has previously been identified. However, the role of root hydrotropism in plant growth and survival under natural conditions has not yet been proven. This study assessed how hydrotropic response contributes to drought avoidance in nature.
  
  
  METHODS
  An experimental system was established for the study of Arabidopsis hydrotropism in soil. Characteristics of hydrotropism were analysed by comparing the responses of the miz1 mutant, transgenic plants overexpressing MIZ1 (MIZ1OE) and wild-type plants.
  
  
  RESULTS
  Wild-type plants developed root systems in regions with higher water potential, whereas the roots of miz1 mutant plants did not show a similar response. This pattern of root distribution induced by hydrotropism was more pronounced in MIZ1OE plants than in wild-type plants. In addition, shoot biomass and the number of plants that survived under drought conditions were much greater in MIZ1OE plants.
  
  
  CONCLUSIONS
  These results show that hydrotropism plays an important role in root system development in soil and contributes to drought avoidance, which results in a greater yield and plant survival under water-limited conditions. The results also show that MIZ1 overexpression can be used for improving plant productivity in arid areas.
authors: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors: Satoru
authors: S
authors: Iwata
authors: Yutaka
authors: Y
authors: Miyazawa
authors: Nobuharu
authors: N
authors: Fujii
authors: Hideyuki
authors: H
authors: Takahashi
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D030821:Plants, Genetically Modified; D013534:Survival; D018523:Tropism / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C519512:mizu-kussei1 protein, Arabidopsis
keywords: Arabidopsis thaliana; MIZU-KUSSEI1 (MIZ1); drought avoidance; hydrotropism; root system
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