Xwang:Research: Difference between revisions
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<div> '''Why study maize endosperms ?''' </div> | <div> '''Why study maize endosperms ?''' </div> | ||
Endosperm is biologically and economically important. In all angiosperms, endosperm provides nutrients and signals to the embryo during seed development and/or the seedling during germination. In cereal grains, endosperm comprises a large proportion of the mature seed, contains large amounts of carbohydrates and proteins, and is an important source of food, feed, and industrial raw materials. Approximately, 50% of human calories are derived from cereal endosperm, either directly or indirectly through animal feed. Furthermore, cereal endosperm is used as a raw material for numerous industrial products including ethanol. Therefore, an understanding of how endosperm development is controlled will contribute to improving seed yield in cereal crops with direct and indirect beneficial effects on human nutrition and economic development. | |||
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<div> '''Development of maize endosperm ?''' </div> | |||
Endosperm is formed when the two sperm nuclei inside a pollen grain reach the interior of an embryo sac or female gametophyte. One sperm nucleus fertilizes the egg, forming a zygote, while the other sperm nucleus usually fuses with the two polar nuclei at the center of the embryo sac, forming a primary endosperm cell (its nucleus is often called the triple fusion nucleus). This cell created in the process of double fertilization develops into the endosperm. Because it is formed by a separate fertilization, the endosperm constitutes an organism separate from the embryo.</div> | |||
<div> The early period of endosperm development encompass three phases. In the first 2 days after pollination (DAP) endosperm goes into the syncytial phase in which many rounds of mitosis take place without cytokinesis, resulting in the formation of a multi-nucleated cell. In the third and fourth DAP, the cell walls are formed to encompass the endosperm nuclei which is called cellularization phase. Thereafter, the endosperm undergoes a period of intense mitosis called mitosis phase. From approximately 8 to 10 days after pollination, the endoresperm enters the endoreduplication phase in which many rounds of DNA replication take place without chromatid segregation and cytokinesis. However, the molecular mechanism of endosperm development, the genes regulating the stage transition, and the relationship between endosperm and embryo has not been fully understood </div> | |||
[[Image:endo.jpg | 790 px]] | |||
Revision as of 17:23, 12 March 2011
PROJECT 1. Regulation of early endosperm development in maize
We are currently collaborating with Dr. Brian Larkins and Ramin Yadegari on a NSF funded project to study the regulation of maize early endosperm development. In this project we are using Illumina high-throughput sequencing to profile the mRNA transcriptome (RNA-Seq) to identify the core transcription factors, and build the regulatory network that controls the maize endosperm development in early stages.
See the UA news for the description of this project at [1]
Why study maize endosperms ?
Endosperm is biologically and economically important. In all angiosperms, endosperm provides nutrients and signals to the embryo during seed development and/or the seedling during germination. In cereal grains, endosperm comprises a large proportion of the mature seed, contains large amounts of carbohydrates and proteins, and is an important source of food, feed, and industrial raw materials. Approximately, 50% of human calories are derived from cereal endosperm, either directly or indirectly through animal feed. Furthermore, cereal endosperm is used as a raw material for numerous industrial products including ethanol. Therefore, an understanding of how endosperm development is controlled will contribute to improving seed yield in cereal crops with direct and indirect beneficial effects on human nutrition and economic development.
Development of maize endosperm ?
Endosperm is formed when the two sperm nuclei inside a pollen grain reach the interior of an embryo sac or female gametophyte. One sperm nucleus fertilizes the egg, forming a zygote, while the other sperm nucleus usually fuses with the two polar nuclei at the center of the embryo sac, forming a primary endosperm cell (its nucleus is often called the triple fusion nucleus). This cell created in the process of double fertilization develops into the endosperm. Because it is formed by a separate fertilization, the endosperm constitutes an organism separate from the embryo. The early period of endosperm development encompass three phases. In the first 2 days after pollination (DAP) endosperm goes into the syncytial phase in which many rounds of mitosis take place without cytokinesis, resulting in the formation of a multi-nucleated cell. In the third and fourth DAP, the cell walls are formed to encompass the endosperm nuclei which is called cellularization phase. Thereafter, the endosperm undergoes a period of intense mitosis called mitosis phase. From approximately 8 to 10 days after pollination, the endoresperm enters the endoreduplication phase in which many rounds of DNA replication take place without chromatid segregation and cytokinesis. However, the molecular mechanism of endosperm development, the genes regulating the stage transition, and the relationship between endosperm and embryo has not been fully understood
