The temperature-sensitive brush mutant of the legume Lotus japonicus reveals a link between root development and nodule infection by rhizobia.
The brush mutant of Lotus japonicus exhibits a temperature-dependent impairment in nodule, root, and shoot development. At 26 degrees C, brush formed fewer nodules, most of which were not colonized by rhizobia bacteria. Primary root growth was retarded and the anatomy of the brush root apical meristem revealed distorted cellular organization and reduced cell expansion. Reciprocal grafting of brush with wild-type plants indicated that this genotype only affected the root and that the shoot phenotype was a secondary effect. The root and nodulation phenotype cosegregated as a single Mendelian trait and the BRUSH gene could be mapped to the short arm of chromosome 2. At 18 degrees C, the brush root anatomy was rescued and similar to the wild type, and primary root length, number of infection threads, and nodule formation were partially rescued. Superficially, the brush root phenotype resembled the ethylene-related thick short root syndrome. However, treatment with ethylene inhibitor did not recover the observed phenotypes, although brush primary roots were slightly longer. The defects of brush in root architecture and infection thread development, together with intact nodule architecture and complete absence of symptoms from shoots, suggest that BRUSH affects cellular differentiation in a tissue-dependent way.
Maekawa-Yoshikawa
Makoto
M
University of Munich, 82152 Munich-Martinsried, Germany.
Müller
Judith
J
Takeda
Naoya
N
Maekawa
Takaki
T
Sato
Shusei
S
Tabata
Satoshi
S
Perry
Jillian
J
Wang
Trevor L
TL
Groth
Martin
M
Brachmann
Andreas
A
Parniske
Martin
M
D000040:Abscisic Acid / Q000494:pharmacology; D032461:Chromosomes, Plant / Q000235:genetics; D005030:Ethylenes / Q000494:pharmacology; D017343:Genes, Plant; D005838:Genotype; D005875:Gibberellins / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D000070116:Lotus / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D018520:Plant Shoots / Q000166:cytology / Q000187:drug effects / Q000382:microbiology; D012231:Rhizobium / Q000187:drug effects / Q000502:physiology*; D053204:Root Nodules, Plant / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000382:microbiology*; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature
D005030:Ethylenes; D005875:Gibberellins; D007210:Indoleacetic Acids; D013395:Sucrose; D000040:Abscisic Acid; C036216:ethylene; C007842:gibberellic acid