中文 |

Research Progress

Manganese Toxicity Affects Root Growth by Mediating Auxin Distribution in Arabidopsis

Mar 17, 2017

Manganese (Mn) is one of the essential micronutrient elements and is necessary for plant growth and development. Most studies on the physiological mechanisms of plant responses to Mn toxicity were focused on Mn-inhibited photosynthesis, Mn-mediated changes in antioxidative enzymes, and reactive oxygen species production. However, whether and how Mn toxicity affects root growth by mediating auxin distribution and response in roots remains poorly understood. 

Prof. XU Jin and his team from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences conducted a study to investigate the role of auxin in Mn-mediated inhibition of primary root (PR) growth in Arabidopsis using physiological and genetic approaches.

They characterized Mn-inhibited root growth and described altered patterns of auxin accumulation and distribution in the PR of Mn-treated roots. 

Wild-type Arabidopsis col-0 was used in their study. The following mutant and transgenic Arabidopsis lines were used: pin4-3pin7-2, and DR5:GUSDII-VENUSPIN1:PIN1-GFPPIN2:PIN2-GFPPIN4:PIN4-GFPPIN7:PIN7-GFPAUX1:AUX1-YFPCYCB1;1:GUS.

They found that Mn toxicity reduced DR5:GUS expression whereas it increased DII-VENUS fluorescent signal in the root tips, indicating that exposure to excess Mn resulted in PR growth inhibition by reducing auxin accumulation in root tips. 

Mn toxicity decreased auxin accumulation in roots by reducing auxin biosynthesis and repressing auxin transport via the decrease of the expression of auxin efflux carriers PIN4 and PIN7. 

Loss of function pin4 and pin7 mutants showed less inhibition of root growth than col-0 seedlings. 

This study indicates that Mn toxicity inhibited PR growth by reducing auxin biosynthesis and repressing the expression of auxin efflux transporters PIN4 and PIN7 to reduce auxin levels in root tips, resulting in reduced root meristematic cell division. 

The study entitled “Manganese Toxicity Inhibited Root Growth by Disrupting Auxin Biosynthesis and Transport in Arabidopsis” has been published in Frontiers in Plant Science.

Contact Us
  • 86-10-68597521 (day)

    86-10-68597289 (night)

  • 86-10-68511095 (day)

    86-10-68512458 (night)

  • cas_en@cas.cn

  • 52 Sanlihe Rd., Xicheng District,

    Beijing, China (100864)

Copyright © 2002 - Chinese Academy of Sciences