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Published on: December 23, 2017
New nodulation mutants responsible for infection thread development in Lotus japonicus
Koji Yano1, Myra L Tansengco, Taihei Hio
1Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan.
Molecular Plant-Microbe Interactions : MPMI
|July 15, 2006
Summary
Researchers identified five new mutants in the model legume Lotus japonicus that disrupt symbiotic nodule development. These mutants show defects in infection thread formation, crucial for nitrogen fixation, offering insights into legume-host genetic regulation.
Area of Science:
- Plant Biology
- Symbiotic Interactions
- Genetics
Background:
- Legume plants form symbiotic relationships with rhizobia bacteria in root nodules.
- This symbiosis is essential for biological nitrogen fixation, a key process in agriculture.
- Nodule development is initiated by bacteria but controlled by host plant genes.
Purpose of the Study:
- To identify and characterize plant genes regulating symbiotic nodule development in Lotus japonicus.
- To understand the genetic basis of infection thread formation during symbiosis.
Main Methods:
- Ethylmethane sulfonate mutagenesis was used to create mutants in Lotus japonicus.
- Five nodulation mutants (Ljsym74-3, Ljsym79-2, Ljsym79-3, Ljsym80, Ljsym82) were isolated and analyzed.
- Mutants were phenotyped for nodule development and infection thread progression after inoculation with Mesorhizobium loti.
Main Results:
- All five mutants displayed defects in functional nodule development and nitrogen starvation symptoms.
- Infection thread development was aborted in all mutants, leading to nodules lacking infected cells.
- Ljsym74-3 and Ljsym80 showed thick infection threads in short root hairs; Ljsym82 had early infection thread abortion.
Conclusions:
- Mutants Ljsym74-3, Ljsym79-2, and Ljsym79-3 were found to be allelic to known Lotus japonicus mutants (alb1 and crinkle).
- The study identified novel genetic factors controlling infection thread development and symbiotic nodule formation.
- Further map-based cloning and characterization will elucidate the genetic mechanisms underlying infection thread development in Lotus japonicus.
