Melatonin regulates root meristem by repressing auxin synthesis and polar auxin transport in arabidopsis

Qiannan Wang, Bang An, Yunxie Wei, Russel J. Reiter, Haitao Shi, Hongli Luo, Chaozu He

Research output: Contribution to journalArticlepeer-review

114 Scopus citations


Melatonin (N-acetyl-5-methoxytryptamine) plays important roles in regulating both biotic and abiotic stress tolerance, biological rhythms, plant growth and development. Sharing the same substrate (tryptophan) for the biosynthesis, melatonin and auxin also have similar effects in plant development. However, the specific function of melatonin in modulating plant root growth and the relationship between melatonin and auxin as well as underlying mechanisms are still unclear. In this study, we found high concentration of melatonin remarkably inhibited root growth in Arabidopsis by reducing root meristem size. Further studies showed that melatonin negatively regulated auxin biosynthesis, the expression of PINFORMED (PIN) proteins as well as auxin response in Arabidopsis. Moreover, the root growth of the triple mutant pin1pin3pin7 was more tolerant than that of wild-type in response to melatonin treatment, suggesting the essential role of PIN1/3/7 in melatonin-mediated root growth. Combination treatment of melatonin and 5-Triiodobenzoic acid (TIBA) did not enhance melatonin-mediated reduction of root meristem size, indicating that polar auxin transport (PAT) may be necessary for the regulation of root meristem size by melatonin treatment. Taken together, this study indicates that melatonin regulates root growth in Arabidopsis, through auxin synthesis and polar auxin transport, at least partially.

Original languageEnglish (US)
Article number1882
JournalFrontiers in Plant Science
Issue numberDECEMBER2016
StatePublished - Dec 15 2016


  • Arabidopsis
  • Auxin
  • Auxin synthesis
  • Melatonin
  • Polar auxin transport
  • Root meristem

ASJC Scopus subject areas

  • Plant Science


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