Bio-fertilizers soil enrichment!

Soil diagnosis

Development of technologies for sustainable society

Crop breeding!

Research topic -1 : Molecular interactions between legume and rhizobia

Infection strategies of rhizobacteria 　 Type III secretion systems (T3SS) play an essential role in the pathogenicity of many pathogenic bacteria. Pathogenic bacteria use the T3SS to deliver effector proteins directly into eukaryotic cells to manipulate host cellular processes to promote pathogenicity. We found that rhizobial T3SS promotes symbiosis with host legumes. We are currently working on molecular mechanism to understand how T3SS promotes symbiosis and how plants distinguish pathogens and symbionts.!

＋ Wildtype rhizobia ＋ T3SS mutant

Interaction between legume plants and nitrogen-fixing bacteria (rhizobia) results in development of root nodule symbiosis. The rhizobia in the nodule fix atmospheric N2 to NH3, which can be effectively utilized by host legume plants. !

Soybean Soybean

Nodule

Legume Rhizobium Photosynthesis

Rhizobium inside Nodule

(Pea, soybean etc.)

!"##"

Nodule

- + Rhizobium

N2

NH3 Rhizobium!

Inside nodule

Outer membrane

Inner membrane

Plasma membrane

Type III pilus

Translocator

cell

Putative structure of T3SS

Cytoplasm

Host cell

Bacterial

Cell wall

Basal body

（Troisfontaines & Cornelis 2005）!

Effectors

454 DNA sequencer!

7,114,474 bp (chromosome)!

736,123 bp (plasmid)!

Genome size!7,850,597 bp!

Genome analysis of DOA9

Genes related to nitrogen fixation were identified in the plasmid.

Collection and isolation of Nitrogen-fixing endophytic bacteria

Research topic -2 : Genome analysis of Nitrogen-fixing endophytic bacteria

Soil samples from 16 different sources in Thailand

Rice, Soybean etc.

Trap plant

Bacterial re-isolation re-inoculation

60 Endophytic Strains

Thailand

N2-fixing strains including DOA9 !!

Bacteria living inside plant. It often gives plant beneficial traits such as nutrients, resistance to pathogens and drought tolerance.

Endophytic bacteria :