Amino Acid Overproducing Crop Plants Selected by Resistance to Feedback Inhibition of Amino Acid Biosynthesis

Research Project

Project/Area Number	60560011
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Breeding science
Research Institution	Radiation Center of Osaka Prefecture
Principal Investigator	INOUE Masayoshi (1986) Radiation Center of Osaka Prefecture, Senior Researcher, その他, その他 (90090456) 長谷川博阪府放中研, 研究員
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1985: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywords	Rice / Amino acid analog / Lysine / Threonine / Mutation / 抵抗性品種
Research Abstract	For the purpose of breeding high lysine and/or threonine content rice, the selection of mutants resistant to lysine plus threonine (LT) or lysine analogs and the screening of LT resistant varieties were carried out. The results of screening of hydroxy-L-proline (Hyp) varieties was also reported. 1. Twenty seedlings resistant to LT were selected from 28,800 <M_2> population mutagenized by 20 and 30 krad gamma-rays. Fourteen progenies of the selected seedlings showed LT resistance in <M_4> . Free threonine content in the 14-day-old seedlings of some LT resistant <M_4> lines were more than twice of that of the original variety, 'Nipponbare'. In particular, three lines also showed higher free lysine content (more than 5-fold) than that of the original variety. 2. No mutants resistant to lysine analogs were obtained in the <M_2> population mutagenized by gamma-ray or sodium azide (alone or combined with ethidium bromide). 3. The relationship between resistance to LT and free amino acid content was studied in 10 varieties, which had shown differences in the degree of LT resistance. Two varieties, which were classified as LT resistant, showed high free threonine content in the 14-day-old seedlings. Furthermore, 173 varieties were screened for LT resistane as a parameter of high threonine content. Only one out of 18 LT resistant varieties showed high free threonine content in the seedlings. 4. No varieties resistant to Hyp were found in 98 varieties screened.