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A new cell death regulator identified in plants


​​Researchers at the Biosciences and Biotechnologies Institute of Aix-Marseille (CEA-Biam) have identified a new regulatory gene controlling cell death induced in plants by conditions of excess light energy. The study of this gene could help in increasing plant resistance towards environmental stresses.​
Published on 15 February 2016
CEA-Biam researchers are interested in genes that are activated by light conditions leading to cell death in plants. Photosynthesis is oxygenic and, as such, it can produce various reactive oxygen species including singlet-excited oxygen (1O).The latter molecule can act as a signal that modifies gene expression and leads to cell death.
Biologists have investigated the OXI1* gene encoding a serine/threonine kinase** protein, previously found to be involved in the response of plants to pathogens. This gene is strongly induced in the model plant Arabidopsis thaliana exposed to increased light intensities. An Arabidospis mutant lacking OXI1 was much more resistant to oxidative stress than its wild-type counterpart under the same conditions of high light stress and the same production of singlet oxygen. This phenomenon was cancelled by spraying the plants with jasmonate, a phytohormone derivated from lipid oxidation, whose role in cell death has been demonstrated in previous studies. This study shows that the OXI1 kinase acts upstream of jasmonate through a different regulation pathway that the one previously identified in plants exposed to pathogen attacks. 
Thus, the OXI1 gene has been identified as a new regulator controlling cell death induced by high light. This finding provides a potential target for increasing plant resistance to environmental constraints (drought, cold, heat, …).

Picture legend : Autoluminescence picture of lipid peroxidations induced by light in Arabidopsis. Cell damages and lipid oxidations are weak in the oxi1 mutant lacking kinase OXI1 (right) compared to the wild (left).​

* Oxidative signal inducive 1
** Enzyme that catalyses phosphorylation reactions

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