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Manganese transport is essential for N 2 ‐fixation by Rhizobium leguminosarum in bacteroids from galegoid but not phaseoloid nodules
Author(s) -
Hood Graham,
Ramachandran Vinoy,
East Alison K.,
Downie J. Allan,
Poole Philip S.
Publication year - 2017
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 - 10.1111/1462-2920.13773
Subject(s) - rhizobium leguminosarum , biology , pisum , vicia faba , mutant , rhizobia , sativum , symbiosis , nitrogen fixation , phaseolus , rhizobium , botany , microbiology and biotechnology , rhizobiaceae , biochemistry , genetics , gene , bacteria
Summary Rhizobium leguminosarum has two high‐affinity Mn 2+ transport systems encoded by sitABCD and mntH . In symbiosis, sitABCD and mntH were expressed throughout nodules and also strongly induced in Mn 2+ ‐limited cultures of free‐living cells. Growth of a sitA mntH double mutant was severely reduced under Mn 2+ limitation and sitA and mntH single mutants were more sensitive to oxidative stress. The double sitA mntH mutant of R. leguminosarum was unable to fix nitrogen (Fix ‐ ) with legumes belonging to the galegoid clade ( Pisum sativum , Vicia faba and Vicia hirsuta ). The presence of infection thread‐like structures and sparsely‐packed plant cells in nodules suggest that bacteroid development was blocked, either at a late stage of infection thread progression or during bacteroid‐release. In contrast, a double sitA mntH mutant was Fix + on common bean ( Phaseoli vulgaris ), a member of the phaseoloid clade of legumes, indicating a host‐specific symbiotic requirement for Mn 2+ transport.