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Sinorhizobium fredii HH103 syrM inactivation affects the expression of a large number of genes, impairs nodulation with soybean and extends the host‐range to Lotus japonicus
Author(s) -
AcostaJurado Sebastián,
AliasVillegas Cynthia,
NavarroGómez Pilar,
Almozara Andrés,
RodríguezCarvajal Miguel A.,
Medina Carlos,
Vinardell JoséMaría
Publication year - 2020
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14897
Subject(s) - biology , lotus japonicus , sinorhizobium , mutant , gene , lotus , genetics , symbiosis , gene expression , rhizobia , microbiology and biotechnology , botany , bacteria
Summary Sinorhizobium fredii HH103 Rif R is a broad host‐range rhizobial strain able to nodulate with soybean and Lotus burttii , but it is ineffective with L. japonicus . Here, we study the role of the HH103 Rif R SyrM protein in the regulation of gene expression and its relevance in symbiosis with those three legumes. RNAseq analyses show that HH103 SyrM is an important transcriptional regulator not only in the presence of inducer flavonoids but also in its absence. Lack of SyrM increases Nod factors production and decreases genistein‐mediated repression of exopolysaccharide production in HH103. In symbiosis, mutation of syrM partially impaired interaction with soybean but improves effectiveness with L. burttii and extends the host‐rage to L. japonicus Gifu. In addition, HH103 syrM mutants enter in both Lotus species by infection threads, whereas HH103 uses the more primitive intercellular infection to enter into L. burttii roots These symbiotic phenotypes were previously observed in two other HH103 mutants affected in symbiotic regulators, nodD2 and nolR , revealing that in S. fredii HH103 numerous transcriptional regulators finely modulate symbiotic gene expression.