TY - JOUR
T1 - Deregulation of a Ca2+/calmodulin-dependent kinase leads to spontaneous nodule development
AU - Tirichine, Leïla
AU - Imaizumi-Anraku, Haruko
AU - Yoshida, Satoko
AU - Murakami, Yasuhiro
AU - Madsen, Lene H.
AU - Miwa, Hiroki
AU - Nakagawa, Tomomi
AU - Sandal, Niels
AU - Albrektsen, Anita S.
AU - Kawaguchi, Masayoshi
AU - Downie, Allan
AU - Sato, Shusei
AU - Tabata, Satoshi
AU - Kouchi, Hiroshi
AU - Parniske, Martin
AU - Kawasaki, Shinji
AU - Stougaard, Jens
PY - 2006/6/29
Y1 - 2006/6/29
N2 - Induced development of a new plant organ in response to rhizobia is the most prominent manifestation of legume root-nodule symbiosis with nitrogen-fixing bacteria. Here we show that the complex root-nodule organogenic programme can be genetically deregulated to trigger de novo nodule formation in the absence of rhizobia or exogenous rhizobial signals. In an ethylmethane sulphonate-induced snf1 (spontaneous nodule formation) mutant of Lotus japonicus, a single amino-acid replacement in a Ca2+/calmodulin- dependent protein kinase (CCaMK) is sufficient to turn fully differentiated root cortical cells into meristematic founder cells of root nodule primordia. These spontaneous nodules are genuine nodules with an ontogeny similar to that of rhizobial-induced root nodules, corroborating previous physiological studies. Using two receptor-deficient genetic backgrounds we provide evidence for a developmentally integrated spontaneous nodulation process that is independent of lipochitin-oligosaccharide signal perception and oscillations in Ca 2+ second messenger levels. Our results reveal a key regulatory position of CCaMK upstream of all components required for cell-cycle activation, and a phenotypically divergent series of mutant alleles demonstrates positive and negative regulation of the process.
AB - Induced development of a new plant organ in response to rhizobia is the most prominent manifestation of legume root-nodule symbiosis with nitrogen-fixing bacteria. Here we show that the complex root-nodule organogenic programme can be genetically deregulated to trigger de novo nodule formation in the absence of rhizobia or exogenous rhizobial signals. In an ethylmethane sulphonate-induced snf1 (spontaneous nodule formation) mutant of Lotus japonicus, a single amino-acid replacement in a Ca2+/calmodulin- dependent protein kinase (CCaMK) is sufficient to turn fully differentiated root cortical cells into meristematic founder cells of root nodule primordia. These spontaneous nodules are genuine nodules with an ontogeny similar to that of rhizobial-induced root nodules, corroborating previous physiological studies. Using two receptor-deficient genetic backgrounds we provide evidence for a developmentally integrated spontaneous nodulation process that is independent of lipochitin-oligosaccharide signal perception and oscillations in Ca 2+ second messenger levels. Our results reveal a key regulatory position of CCaMK upstream of all components required for cell-cycle activation, and a phenotypically divergent series of mutant alleles demonstrates positive and negative regulation of the process.
UR - http://www.scopus.com/inward/record.url?scp=33646684841&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646684841&partnerID=8YFLogxK
U2 - 10.1038/nature04862
DO - 10.1038/nature04862
M3 - Article
C2 - 16810257
AN - SCOPUS:33646684841
VL - 441
SP - 1153
EP - 1156
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7097
ER -