Teng Kaichong, Zhao Neng, Xie Yonghong, Li Rongbai, Li Jianxiong
State Key Laboratory for Conservation and Utilization of Subtropical Agri-Bioresources, College of Agriculture, Guangxi University, Nanning 530004, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agri-Bioresources, College of Agriculture, Guangxi University, Nanning 530004, China.
J Adv Res. 2024 Dec 17. doi: 10.1016/j.jare.2024.12.013.
The floret of rice is a main component of the spikelet, and the ovule of pistil is a critical organ for successful reproduction and determines the number of seeds. However, the molecular mechanisms underlying the ovule development remain elusive.
Twin-seedling rice has great potential for application in rice production. The study was to isolate the gene that controls twin-seedling in rice and explore the molecular function of the gene in floret development.
We discovered a twin-seedling rice (tsr) mutant and constructed different segregating populations to clone TSR gene using map-based cloning method. To explore the molecular functions of TSR in determination of the ovary number and development, we applied molecular technologies such as yeast two-hybrid assay, electrophoretic mobility shift assay (EMSA), and dual-LUC transient expression assay to search for the TSR-interacting proteins and the target genes regulated by TSR.
We report here the map-based cloning of TSR which encodes an AP2/ERF transcription factor. Mutations in TSR lead to occurrence of the twin-seedling rice. The tsr mutant showed open hulls of the spikelets and displayed changes in the number of stamens and ovules of the florets. The ovary of tsr mutant contained two conjugated ovules which developed into a mature seed with two viable embryos. Mechanistic studies revealed that TSR regulates the expression levels of genes related to spikelet determination and ovule identity by binding to their promoters. Furthermore, TSR interacted with OsMADS1 and this interaction allowed OsMADS1 to modulate the transcriptional activityy of TSR on gene expression. The molecular study of TSR provides new insights into the formation and development of rice floret and helps breeders generate twin-seedling rice in production.
水稻小花是小穗的主要组成部分，雌蕊的胚珠是成功繁殖的关键器官，决定种子数量。然而，胚珠发育的分子机制仍不清楚。
双胚苗水稻在水稻生产中具有巨大应用潜力。本研究旨在分离控制水稻双胚苗的基因，并探索该基因在小花发育中的分子功能。
我们发现了一个双胚苗水稻（tsr）突变体，并构建了不同的分离群体，采用图位克隆法克隆TSR基因。为了探究TSR在子房数量确定和发育中的分子功能，我们应用酵母双杂交分析、电泳迁移率变动分析（EMSA）和双荧光素酶瞬时表达分析等分子技术来寻找与TSR相互作用的蛋白以及受TSR调控的靶基因。
我们在此报告TSR的图位克隆，其编码一个AP2/ERF转录因子。TSR中的突变导致双胚苗水稻的出现。tsr突变体表现出小穗颖壳张开，并在小花的雄蕊和胚珠数量上出现变化。tsr突变体的子房包含两个相连的胚珠，发育成一个带有两个有活力胚的成熟种子。机制研究表明，TSR通过结合基因启动子来调节与小穗确定和胚珠身份相关基因的表达水平。此外，TSR与OsMADS1相互作用，这种相互作用使OsMADS1调节TSR对基因表达的转录活性。对TSR的分子研究为水稻小花的形成和发育提供了新见解，并有助于育种者在生产中培育双胚苗水稻。
