@article{oai:repo.qst.go.jp:00082308,
 author = {Yasuda, Michiko and Katsuya, Sato and Yutaka, Ono and Yokoyama, Tadashi and Okazaki, Shin and Katsuya, Sato and Yutaka, Ono},
 journal = {QST Takasaki Annual Report 2019},
 month = {Mar},
 note = {Bacillus pumilus strain TUAT-1 (TUAT-1) promotes the growth of several plants, including that of rice (Oryza sativa L.) and Brassica species. TUAT-1 has been shown to increase shoot and root growth in rice, mustard, radish, and komatsuna, mainly due to its effects to promote nutrient uptake by plant roots. Inoculation of plants with TUAT-1 biofertilizer at sowing and transplanting resulted in significant changes in plant biomass, nutrient uptake, tissue N content, tiller number, root length, and the number of roots in the forage rice. Despite, the large body of experimental evidence on the growth-promoting effects of TUAT-1, our knowledge of the conditions required for consistent positive interaction between the bacteria and the plant in field conditions, is limited. Generally, bacterial inoculation improves plant growth and rice yield, but the effects often change by the soil physical or chemical properties, climate, and target crops. This makes it difficult for TUAT-1 biofertilizers to be utilized more efficiently and widely. Thus, the generation of the TUAT-1 mutants with stable and improved plant growth-promoting effects might be of great importance in biofertilizer development. Therefore, the specific objectives of this study were (i) to determine the best condition for ion beam irradiation to TUAT-1 and (ii) to screen the TUAT-1 mutants with stable and improved plant-growth-promoting effects. The TUAT-1 was irradiated at different doses (0, 100, 150, 250, 500, 1000, 1500, and 2000 Gy) with helium ion beams (4He2+, 50 MeV). Survival rates were determined by comparing the number of colonies per dish and the most appropriate doses to produce mutants were selected as a 150 Gy. The nitric oxide is generally known as a signal which controls various events in plant development including cell division, meristem formation, and defense responses against pathogens. The reduction of nitric oxide by TUAT-1 suggests that the TUAT-1 scavenges nitric oxide to promote its infection and/or induce root development. We therefore aimed to isolate TUAT-1 mutants that possess higher nitric oxide scavenging activity. Our efforts are currently directed toward screening these mutants and we will analyze their plant-growth-promoting activities when we obtain the candidates.},
 pages = {102--102},
 title = {Generation and Screening of Bacillus pumilus Mutants with Improved Plant Growth- Promoting Effects Using Ion-beam},
 volume = {QST-M-29},
 year = {2021}
}