Post-transcriptional reprogramming during root nodule symbiosis

REYNOSO, MAURICIO; TRAUBENIK, SOLEDAD; HOBECKER, KAREN; BLANCO, FLAVIO; ZANETTI, MARÍA EUGENIA

The Model Legume Medicago truncatula

John Wiley & Sons, Inc

Año: 2018; p. 554 - 562

IntroductionPlant cells adjust their genetic programs to generate developmental changes and respond to environmental stimuli, leading to a constant reprogramming of gene expression to adapt the physiological and ecological responses of the whole plant. Legumes establish a mutualistic symbiotic interaction with soil bacteria known as rhizobia, providing an exquisite biological model to study reprogramming of gene expression in a pluricellular eukaryotic organism interacting with its prokaryotic microsymbiont in a variable environmental context, which also impacts on the output of the association. Many studies in this field have focused in the modification of the plant transcriptome during the onset of the interaction, taking advantage of the DNA microarray and direct RNA sequencing (RNA-seq) technologies. As a consequence, most of the information available describes the changes of the steady-state levels of poly A+ RNAs, underestimating the contribution of post-transcriptional levels of regulation that contributes to the reprogramming of gene expression. In the last years, a number of studies have contributed to a more comprehensive understanding of these changes, highlighting the role of endogenous small RNAs (sRNAs), mainly microRNAs (miRNAs) and phased small interfering RNAs (phasiRNAs), as well as the importance of the dynamic of the translational status of mRNAs as key regulators of the gene expression. In this chapter we will summarize the contribution of sRNAs to the genetic responses of the plant during root nodule symbiosis and changes of mRNAs association with the translation machinery in this interaction of ecological and agronomical importance.