Open Accessnif Gene expression in a Nif + , Fix − Bradyrhizobium japanicum variant
Author(s) -
Bradburne James A.,
Mathis James N.,
Israel Daniel W.
Publication year - 1994
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1994.tb07206.x
Subject(s) - nitrogen fixation , mutant , biology , bradyrhizobium japonicum , gene , bradyrhizobium , microbiology and biotechnology , genetics , symbiosis , rhizobiaceae , bacteria
Bradyhizobium japonicum USDA 110 has been shown to contain several genetically similar, naturally occurring colony morphology variants. One of these variants, L2‐110, although devoid of symbiotic nitrogen fixation, retains significant levels of explanta nitrogen fixation ability relative to other symbiotically competent USDA 110 variants (MN‐110 and I‐110). Interestingly, Northern blot analyses revealed that L2‐110 nodules, despite their lack of symbiotic nitrogen fixation, contained 65% the level of mRNA for dinitrogenase ( nif DK) and 64% the level of dinitrogenase reductase ( nif H) mRNA relative to MN‐110 nodules. Western blot analyses of tissue from the same nodules detected 32% the level of dinitrogenase and 31% the level of dinitrogenase reductase in L2‐110 relative to MN‐110. L2‐110 appears to be a new class of mutant based on the complete absence of symbiotic nitrogen fixation (Fix − and the presence of significant exanta nitrogen fixation (Nif + ).