大多數被子植物的種子發育始於「雙重受精」，即兩個精細胞分別使卵細胞和中央細胞受精，進而產生胚與胚乳。儘管胚與胚乳獨立發育，但其過程受到種子形成的共同協調。這種協同作用對於種子的正常發育至關重要，表明其中必有某些「訊號」調節胚與胚乳間的同步發育。然而，這些訊號的具體作用機制目前仍不清楚。在先前的研究中，發現了一些胚胎發育依賴的胚乳特異性基因，這些基因僅在雙重受精的種子中表達，而在僅有中央細胞受精的種子中不表達，這些基因可能是介導胚與胚乳間訊號傳遞的關鍵。我們基於轉錄組數據分析結果，選擇LBD8進行深入研究。為了分析LBD8在阿拉伯芥中的功能，我們利用CRISPR/Cas9技術建立了基因敲除系，並透過比較這些敲除系與野生型植物的表現型及基因表達模式，探討其生物學功能。結果顯示，LBD8對種子至關重要，可能直接影響其發育。本論文旨在幫助理解植物無融合生殖（apomixis）的機制，並將這些發現應用於作物育種。此外，我們也嘗試敲除水稻中的LBD8同源基因，以期加速糧食作物無融合生殖研究的進展。

Seed development in most angiosperms initiates by double fertilization, where two sperm cells fertilize the egg cell and the central cell, producing the embryo and endosperm, respectively. Although the embryo and endosperm develop independently, their development is synchronized during seed formation. Synchronized development of embryo and endosperm is crucial for proper seed development, suggesting that signals must regulate the synchronized development between the embryo and endosperm. However, such regulatory signals have not yet been identified. Previous research has uncovered embryo development-dependent endosperm-specific genes in Arabidopsis, which are expressed only in double-fertilized seeds, but not in seeds where only the central cell is fertilized. These genes are likely to be candidates whose expression is mediated by signal transmission between the embryo and endosperm. Among them, we selected LBD8 for further study. To analyze function of LBD8, we prepared knockout lines of LBD8using CRISPR/Cas9 and compared the phenotypes of lbd8 knockout lines with wild-type plants. Results showed that seed number was drastically reduced in lbd8 when compared with that of wild type. Our regulates indicate that LBD8 is an important for normal seed development. This study aims to contribute to the understanding of the mechanisms underlying plant apomixis and to apply these findings to crop breeding. Additionally, this project attempts to knock out the homologous genes of LBD8 in rice, with the hope of accelerating research progress in apomixis for food crops.

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