Matching Starter Grant awarded in conjunction with NSF Postdoctoral Fellowship in Plant Biology

本研究旨在通过拟南芥胚胎缺陷（emb）突变体的特征，探讨植物胚胎发育的遗传和分子机制。重点是twn1突变体的特征，它在胚胎形态发生中被破坏，并在胚柄中维持细胞类型，以及emb88，一个T-DNA插入突变体，表现出异常的细胞组织和形态发生。研究twn1的具体目标包括：1)构建对植物生长调节剂水平或敏感性发生改变的拟南芥突变体的双突变系；2)表征twn1突变对胚胎后发育的多效性效应。这些研究将有助于深入了解野生型TWN1基因的功能，并阐明突变体TWN1胚柄发生显著胚性转化的机制。emb88的具体目标包括完成emb88基因组位点的表征和emb88 cDNA的分离。本工作旨在阐明EMB88基因产物的生化功能，并为该基因在拟南芥胚胎发生中的长期分子研究提供基础。emb88的分子信息将影响我们对拟南芥胚胎发生和emb突变的理解，因为迄今为止只有少数拟南芥胚胎突变体在分子水平上被表征。同时，twn1和emb88应该提供关于植物胚胎发生的关键过程的有价值的信息，包括胚胎发育中的形态发生、分化细胞类型的维持和细胞间通讯。

The goal of this proposed research is to investigate genetic and molecular mechanisms underlying plant embryo development by characterizing embryo-defective (emb) mutants of Arabidopsis thaliana. Emphasis is on the characterization of the twn1 mutant, which is disrupted in embryonic morphogenesis and maintenance of cell type in the suspensor, and on emb88, a T-DNA insertion mutant that exhibits abnormal cell organization and arrested morphogenesis. Specific goals with twn1 include: 1) constructing double mutant lines with Arabidopsis mutants that have altered levels or sensitivity to plant growth regulators, and 2) characterizing the pleiotropic effects of the twn1 mutation on post embryonic development. These studies should provide insight into the function of the wild type TWN1 gene, and elucidate the mechanism of the dramatic embryogenic transformation observed in the mutant twn1 suspensor. Specific goals with emb88 include completing characterization of the EMB88 genomic locus and isolation of the EMB88 cDNA. This work should elucidate the biochemical function of the EMB88 gene product, and provide the foundation for a long term molecular study of the role of this gene in Arabidopsis embryogenesis. Molecular information on emb88 will have an impact on our understanding of Arabidopsis embryogenesis and emb mutants, because to date only a handful of Arabidopsis embryo mutants have been characterized at the molecular level. Together, twn1 and emb88 should yield valuable information on key processes of plant embryogenesis, including morphogenesis, maintenance of differentiated cell type, and intercellular communication in the developing embryo.