AUTHOR=Valdés-López Oswaldo , Formey Damien , Isidra-Arellano Mariel C. , Reyero-Saavedra Maria del Rocio , Fernandez-Göbel Tadeo F. , Sánchez-Correa Maria del Socorro 

TITLE=Argonaute Proteins: Why Are They So Important for the Legume–Rhizobia Symbiosis?

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 10 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01177

DOI=10.3389/fpls.2019.01177

ISSN=1664-462X

ABSTRACT=Unlike most other land plants, legumes can fulfill their nitrogen needs through the establishment of symbioses with nitrogen-fixing soil bacteria (rhizobia). Through this symbiosis, fixed-nitrogen is incorporated into the food chain. Because of this ecological relevance, the genetic mechanisms underlying the establishment of the legume-rhizobia symbiosis have been extensively studied over the past decades. During this time, different types of regulators of this symbiosis have been discovered and characterized. A growing number of studies have demonstrated the participation of different types of small RNAs, including microRNAs, in the different stages of this symbiosis. The involvement of small RNAs also indicates that Argonaute (AGO) proteins participate in the regulation of the legume-rhizobia symbiosis. However, despite this obvious role, the relevance of AGO proteins in the legume-rhizobia symbiosis has been overlooked and under-studied. Here, we discuss and hypothesize the likely participation of AGO proteins in the regulation of the different steps which enable the establishment of the legume-rhizobia symbiosis. We also briefly review and discuss whether rhizobial symbiosis induces DNA damages in the legume host. Understanding the different levels of legume-rhizobia symbiosis regulation could lead to the development of improved nitrogen fixation efficiency to enhance sustainable agriculture, thereby reducing dependence on inorganic fertilizers.