Legumes plants establish a symbiotic association with soil bacteria, known as rhizobia, which have the ability to fix atmospheric nitrogen. This ecological and agronomical important interaction results in the formation of a post-embryonic root organ, the nodule, within which rhizobia are allocated and reduce atmospheric nitrogen to forms that can be assimilated by the plant. Biological nitrogen fixation allows the incorporation of nitrogen into the soil for its exploitation in agricultural systems at a very low cost, and therefore it is an excellent option to maintain the quality of extensively used agronomic lands. Although in the past years a great progress has been made in the identification of plant genes involved in the signaling pathway required for nodulation, many aspects of the molecular mechanisms that regulate that complex process are still unknown. New technologies associated with transcriptomics have led to the use of stationary levels of messenger RNA as a criterion for the selection and study of genes with possible implication in characters of agronomic importance. This approach has excluded post-transcriptional regulatory levels associated with rapid response by translation of preexisting mRNAs. The general objective of this work is to characterize at genomic scale the dynamic distribution of RNA populations associated with the translation machinery. Elucidation of these mechanisms will provide novel insight into translational reprogramming of gene expression during root nodule symbiosis. The results obtained will allow a better understanding of the biological phenomenon that leads to the biological nitrogen fixation, while expanding the database on which genes with potential use in the improvement of relevant agronomic traits are selected. A better understanding of this would help to alleviate the harmful effects on agriculture.