A new mechanism for regulating gene expression in plants in response to stress?

Produced from the joint work of two LGDP teams led by Julio Sáez-Vásquez and Jean-Philippe Reichheld and by two post-docs - Cyril Charbonnel and Adnan K. Niazi - this article shows for the first time that RNase III enzymes, which are significant players in RNA metabolism, can be regulated by redox reactions in a model plant.

In fact, RNase III family enzymes are capable of cutting double-stranded RNA, an essential step to regulate the treatment of a large number of RNAs such as mRNAs, rRNAs, snoRNAs as well as certain small RNAs including siRNAs and miRNAs. In the model plant Arabidopsis thaliana, one of these RNases III - named RTL1 - binds and specifically cleaves siRNA double-stranded precursor RNAs.
It is worth noting that an amino acid (designated C230 cysteine) located in the RNA binding domain, is sensitive to changes in the cellular redox state (redox), whether or not to allow cleavage of the RNA.

Environnemental regulation

The cellular redox state is controlled by environmental factors such as temperature, light or pathogens. It acts as a sensor of environmental changes that will be relayed to key enzymes of RNA metabolism and thus to gene expression.

Interestingly, this "on/off" mechanism described in Arabidopsis thaliana could be found in other organisms because the amino acid regulated by oxidation-reduction reactions is conserved in other monocotyledonous and dicotyledonous plants of agronomic interest (vine, peas, corn, beans, rice, tomato).