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A non RD receptor‐like kinase prevents nodule early senescence and defense‐like reactions during symbiosis
Author(s) -
Berrabah Fathi,
Bourcy Marie,
Eschstruth Alexis,
Cayrel Anne,
Guefrachi Ibtissem,
Mergaert Peter,
Wen Jiangqi,
Jean Viviane,
Mysore Kirankumar S.,
Gourion Benjamin,
Ratet Pascal
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12881
Subject(s) - rhizobia , adapter molecule crk , biology , mutant , medicago truncatula , microbiology and biotechnology , symbiosis , population , root nodule , gene , signal transduction , genetics , bacteria , demography , sociology , signal transducing adaptor protein
Summary Rhizobia and legumes establish symbiotic interactions leading to the production of root nodules, in which bacteria fix atmospheric nitrogen for the plant's benefit. This symbiosis is efficient because of the high rhizobia population within nodules. Here, we investigated how legumes accommodate such bacterial colonization. We used a reverse genetic approach to identify a M edicago truncatula gene, Sym CRK , which encodes a cysteine‐rich receptor‐like kinase that is required for rhizobia maintenance within the plant cells, and performed detailed phenotypic analyses of the corresponding mutant. The M edicago truncatula sym CRK mutant developed nonfunctional and necrotic nodules. A nonarginine asparate (non RD ) motif, typical of receptors involved in innate immunity, is present in the Sym CRK kinase domain. Similar to the dnf2 mutant, bacteroid differentiation defect, defense‐like reactions and early senescence were observed in the sym CRK nodules. However, the dnf2 and sym CRK nodules differ by their degree of colonization, which is higher in sym CRK . Furthermore, in contrast to dnf2 , sym CRK is not a conditional mutant. These results suggest that in M . truncatula at least two genes are involved in the symbiotic control of immunity. Furthermore, phenotype differences between the two mutants suggest that two distinct molecular mechanisms control suppression of plant immunity during nodulation.