Many protocols have been published in recent years for the extraction of DNA, taking into account the current capacity of sequencing technologies and high-throughput genotyping. The extraction of RNA for studies of gene expression remained at a much smaller flow therefore requires a development effort to be consistent with the technology platforms available for transcriptome analysis. Another constraint not included in the protocols found in the literature is the ability to take samples directly into natural or artificial environment without easy access to a cold source. The development of protocol for use at room temperature is a major challenge to improve our understanding of factors affecting gene regulation in environments away from our laboratories. At last, another important point is the adaptation to the low amount of plant material in order to study gene expression either at the whole plant, but in an organ (leaf, petal, root, ...) or a fragment body weighing between 10 and 100 mg. We have developed a technique to isolate mRNA from Arabidopsis thaliana leaves without using liquid nitrogen or hazardous constituents. The grinding is carried out at room temperature in microtubes to treat a few samples to 96 samples, and to chain the extraction of RNA and DNA from tissue removed, with yields in qPCR or PCR equivalent to those obtained using the protocol standard with mortar and liquid nitrogen. The protocol, requires two hours from leaves grinding to RNA / DNA extracts storage for 96 initial samples, not including the time of collection and the setting tube.