文部省 科学研究費補助金 新学術領域研究 植物発生ロジックの多元的開拓

PubMed ID 25841039 Pubmed 日付 2015/Apr/3
タイトル Axillary Meristem Formation in Rice Requires the WUSCHEL Ortholog TILLERS ABSENT1.
ジャーナル The Plant cell  2015/Apr/3  ()   
著者 Tanaka Wakana W,Ohmori Yoshihiro Y,Ushijima Tomokazu T,Matsusaka Hiroaki H,Matsushita Tomonao T,Kumamaru Toshihiro T,Kawano Shigeyuki S,Hirano Hiro-Yuki HY
抄録 Axillary shoot formation is a key determinant of plant architecture. Formation of the axillary shoot is regulated by initiation of the axillary meristem or outgrowth of the axillary bud. Here, we show that rice (Oryza sativa) TILLERS ABSENT1 (TAB1; also known as Os WUS), an ortholog of Arabidopsis thaliana WUS, is required to initiate axillary meristem development. We found that formation of the axillary meristem in rice proceeds via a transient state, which we term the premeristem, characterized by the expression of OSH1, a marker of indeterminate cells in the shoot apical meristem. In the tab1-1 (wus-1) mutant, however, formation of the axillary meristem is arrested at various stages of the premeristem zone, and OSH1 expression is highly reduced. TAB1/WUS is expressed in the premeristem zone, where it shows a partially overlapping pattern with OSH1. It is likely, therefore, that TAB1 plays an important role in maintaining the premeristem zone and in promoting the formation of the axillary meristem by promoting OSH1 expression. Temporal expression patterns of WUSCHEL-RELATED HOMEOBOX4 (WOX4) indicate that WOX4 is likely to regulate meristem maintenance instead of TAB1 after establishment of the axillary meristem. Lastly, we show that the prophyll, the first leaf in the secondary axis, is formed from the premeristem zone and not from the axillary meristem.

 Axillary Meristem Formation in

東京大学 生物科学専攻 進化遺伝学研究室 平野博之  投稿日時[2015-04-30 15:24:12]

TAB1遺伝子が欠損すると栄養成長期の腋芽が全く形成されず,花序や花の形態も異常となります.本研究の結果,TAB1は腋芽メリステムが形成される非常に初期において,その未分化性を維持するために重要な働きをしていることが明らかとなりました.TAB1はシロイヌナズナのWUSのオーソログですが,イネの完成した茎頂メリステムでは全く発現しておらず,その維持には必要とされないことも判明しました.したがって,WUSのようなシロイヌナズナ発生にきわめて重要な働きをする遺伝子でさえ,単子葉植物の発生においては,異なる発生ロジックのもとで,独自の機能を果たしていると考えられます.