EAGER: Molecular Genetic Analysis of Early Endosperm Development by Microinjection of Maize Embryo Sacs

禾本科植物胚乳的发育有几个不同的阶段：早期发育，包括双受精、合胞体形成和细胞化；分化，包括主要细胞类型(转移细胞、糊粉、淀粉胚乳和胚胎周围细胞)的形成，有丝分裂和内复制时期，以及贮藏化合物的积累；成熟，包括细胞程序性死亡、休眠和干燥。突变分析已经提供了关于影响胚乳发育分化和成熟阶段的基因的知识，但对早期发育及其后果的了解要少得多。对玉米和小麦的研究表明，早期发育过程中细胞分裂的程度对谷物产量起着重要作用，但人们对其遗传基础知之甚少。虽然在大多数谷物中很难研究胚乳的早期发育，但对于玉米来说，这很容易，因为胚囊可以被分离出来，胚乳可以在体外培养。本项目旨在开发一种研究玉米胚乳早期发育的新方法，即在授粉后2-3天(DAP)胚囊内微量注射核酸。这种方法在转化胚乳方面具有优势，因为它不需要与目前生产转基因玉米植株的方法相关的时间和劳动密集型程序。这些实验有相关的风险，但如果成功，可能会对识别调节早期胚乳发育的遗传机制具有变革性作用，结果可以在http://ag.arizona.edu/research/larkinslab/index.htm，上获得，可能具有宝贵的实际应用。

Endosperm development in grasses has several distinct phases: early development, comprising double fertilization, syncytium formation, and cellularization; differentiation, which includes the formation of the main cell types (transfer cells, aleurone, starchy endosperm, and embryo-surrounding cells), the periods of mitosis and endoreduplication, and the accumulation of storage compounds; and maturation, which includes programmed cell death, dormancy, and desiccation. Mutant analysis has provided knowledge regarding genes that influence the differentiation and maturation phases of endosperm development, but much less is known about early development and its consequences. Studies in maize and wheat suggest the extent of cell division during early development plays an important role in grain yield, but little is known about its genetic basis. While it is difficult to study early endosperm development in most cereals, this is easier with maize, because the embryo sac can be isolated and the endosperm cultured in vitro. This project seeks to develop a novel method to investigate early development in maize endosperm by microinjecting nucleic acids into 2-3 days after pollination (DAP) embryo sacs. This approach has advantages for transforming endosperm because it does not require the time and labor-intensive procedures associated with current methods of producing transgenic maize plants. There are risks associated with these experiments, but if successful could be transformative for identifying the genetic mechanisms that regulate early endosperm development and the results, which can be accessed at http://ag.arizona.edu/research/larkinslab/index.htm, could have valuable practical applications.