A model for the ethylene-mediated auxin distribution under Cr(VI) stress in Arabidopsis thaliana

Abstract

Chromium is one of the top 20 highly toxic heavy metals, which affect agricultural land and economically important crops all over the world. The plant responds to cope with the adverse effects caused by exogenous stimuli. The most important plant's growth, as well as stress response components, are the diverse group of phytohormones. Plant root being the first organ that counters soil contaminant, can be severely damaged. Auxin and ethylene are the most important phytohormones of the root growth and development. It is also reported that auxin is and ethylene play acts synergistically against various abiotic stresses. In a recently published article in Plant, Cell, and Environment we reported that high Cr(VI) levels-induced ethylene mediates auxin distribution. We further reported that Cr(VI)-induced ethylene-mediated auxin is involved in the primary root growth inhibition. In the current, study we proposed a functional model for the Cr(V)-induced ethylene-mediated root growth inhibition by modulating cell cycle and auxin distribution.

Keywords: arabidopsis; auxin: cell cycle; ethylene; growth.

Figure 1.

A model for the Cr(VI)-induced ethylene biosynthesis and signaling. Model shows that Cr(VI) induces ethylene biosynthesis by enhancing the expression level of ACS and ACO encoding genes. Induced ethylene biosynthesis mediates induced ethylene perception that mediates the CTR1 modulated EIN2 phosphorylation. The phosphorylated EIN2 stabilizes EIN3 and regulates EIN3/EIL dependent transcription. Finally, the ethylene pathway activates the auxin polar transporter AUX1 mediated induced auxin accumulation. It inhibits the cell cycle. Taken together, the model shows that the pathway ends with the primary root growth inhibition.