A molecular mechanism unique to hydrotropism in roots

Yutaka Miyazawa, Yoshie Ito, Teppei Moriwaki, Akie Kobayashi, Nobuharu Fujii, Hideyuki Takahashi

Research output: Contribution to journalReview articlepeer-review

16 Citations (Scopus)


Plants are sessile in nature and must respond to various environmental cues to regulate their growth orientation. Root hydrotropism, a response to moisture gradients, has been considered to play an important role in drought avoidance. Nonetheless, the processes underlying hydrotropism in roots have remained obscure until recently because of the interfering effect of gravitropism. To shed light on root hydrotropism, we isolated and analyzed two Arabidopsis mutants, mizu-kussei (miz) 1 and 2, that have abnormal hydrotropic responses but normal responses to gravity. MIZ1 encodes a protein of unknown function with a conserved domain at its C-terminus. MIZ2 encodes a guanine-nucleotide exchange factor for ADP-ribosylation factor-type G proteins, which has been identified as GNOM. These findings suggest that roots possess molecular mechanisms essential for hydrotropism but independent of gravitropism. One of such mechanisms involves vesicle transport unique to hydrotropism in roots. Here we summarize recent progress on the molecular mechanism of root hydrotropism and the roles of MIZ1 and MIZ2.

Original languageEnglish
Pages (from-to)297-301
Number of pages5
JournalPlant Science
Issue number4
Publication statusPublished - 2009 Oct


  • GNOM
  • Gravitropism
  • Hydrotropism
  • Root tropism
  • mizu-kussei (miz)

ASJC Scopus subject areas

  • Genetics
  • Agronomy and Crop Science
  • Plant Science


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