報告書番号

U99032

タイトル（和文）

分子育種法による高鉄含量レタスの作出（その４） -－フェリチン遺伝子の後代への遺伝と成長量の増加－-

タイトル（英文）

Molecular breeding of high iron content lettuce (Lactuca sativa L.) (Part4)Inheritance of transferred ferritin gene and enhanced growth of transgenic plants containing ferritin gene

概要 （図表や脚注は「報告書全文」に掲載しております）

著者らは、これまでに,鉄貯蔵タンパク質フェリチンの遺伝子をレタスやイネへ導入することにより,高鉄含有量品種の育成の目処をつけきた.今後、育種を進めるにあたり、外来フェリチン遺伝子の存在様式と後代への遺伝について明らかにする必要が有る。一方，フェリチンは鉄の貯蔵以外に,鉄が関与する酸化ストレスの抑制にも関与することが知られている.本研究では,染色体に外来遺伝子が１～２コピー組み込まれていることや、断片長について特定した。また、外来遺伝子がメンデルの法則に則って遺伝することを確認した。次に、フェリチン遺伝子の発現により,レタスなどの成長が早まることを示した.すなわち，発芽初期では,コントロールより27-42%生重量が勝っていた.また，3ヶ月後の成長量も形質転換体が優れており,その開花時期も早まっていた.これらの光合成速度は,コントロールより高まっていた．さらに次世代の種子重量も増加していた.

概要 （英文）

We have produced transgenic lettuce plants accumulating an iron storage protein ferritin to fortify lettuce with iron. In this study, we obtained 2 main results. One was the integration pattern and the inheritance of the exogenous ferritin gene in transgenic lettuce plants. The other was the growth enhancement of transgenic plants containing ferritin gene. The primary transformants (T0 generation) and their progenies were selected by kanamycin (Km). Southern blot analysis of exsogenous genes in the transformants suggests that 1 or 2 intact ferritin gene(s) was(were) integrated into host genome. The fresh weights of all T1 transformed lines were heavier than that of the control plants 2 weeks after sowing. The heaviest transgenic line was 1.4 times than the weight of control plants. These transgenic lines were subsequently grown for 3 months. Five of the 6 transgenic lines tested were taller than that of the controls. The average height of the tallest line was 91 cm which was over 30 cm taller than that of the controls (56 cm). Flower buds were observed in transformants but flower buds of control plants had not yet formed. There was no apparent relationship between iron content and growth. A similar tendency towards greater growth was obtained from the seeds (T2 generation) of the transformed lines. The rates of photosynthesis in the transgenic lines were approximately 1.5 to 1.8 times greater than that of the control plants. The rate in controls was 1.55 mg-CO2/sec/m2. The maximum rate of photosynthesis of transgenic lines was 2.76 mg-CO2/sec/m2. These results demonstrate the possibility of producing lettuce plants with a high yield and rapid growth rate.

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