Differential analysis of host small RNAs identified conserved and new miRNAs that affect nodulation and strain selectivity in the Phaseolus vulgaris‐ Rhizobium etli symbiosis

CASTAINGTS, MELISSE; KIROLINKO, CRISTINA; RIVERO, CLAUDIO; ARTUNIAN, JENNIFER; VILLAGRA MANCINI, ULISES; BLANCO, FLAVIO ANTONIO; ZANETTI, MARÍA EUGENIA

NEW PHYTOLOGIST

WILEY-BLACKWELL PUBLISHING, INC

Año: 2022

0028-646X

Phaseolus vulgaris plants from the Mesoamerican center of genetic diversification establish a preferential and more efficient root nodule symbiosis with sympatric Rhizobium etli strains. This is mediated by changes in host gene expression, which might occur either at transcriptional or post-transcriptional level. However, the implication of small RNAs (sRNAs)-mediated control of gene expression in strain selectivity has remained elusive.sRNA sequencing was used to identify host microRNAs (miRNAs) differentially regulated in roots at early stages of the symbiotic interaction, which were further characterized by applying a reverse genetic approach.In silico analysis identified known and new miRNAs that accumulated to higher levels in the preferential and more efficient interaction. One of them, designated as Pvu-miR5924, participates in the mechanisms that determine the selection of R. etli strains that will colonize the nodules. In addition, functional analysis of Pvu-miR390b verified that this miRNA is a negative modulator of nodule formation and bacterial infection.This study not only extended the list of miRNAs identified in P. vulgaris, but also enabled the identification of miRNAs that play relevant functions in nodule formation, rhizobia infection and the selection of the rhizobia strains that will occupy the nodule.