葉子衰老是發育過程的最後階段，最後導致器官死亡。該過程處於遺傳編程序列的控制之下，稱之為程序細胞死亡。葉綠體是最早在葉片衰老過程中經歷降解的胞器，當類囊體膜被破壞時，進而葉綠素發生降解。在先前我們已經調查到衰老相關基因Os08g0495800（OsakαGal），其編碼為水稻中特異性的鹼性α-半乳糖苷酶。 OsakαGal是一種二半乳糖基二酰基甘油（DGDG）降解酶，此酵素與葉綠體降解過程中類囊體膜的分解有關。我們的研究目的是確定在OsakαGal基因中如何被轉錄因子調節，並且被激發OsAkaGal基因的基因功能。我們從OsakαGal基因起始密碼子複製了上游1kb DNA序列片段，並用來做高效率酵母雜交篩選的誘餌，並使用由來自水稻（Oryza sativa cv. Nipponbare）的1100個轉錄因子組成的基因庫。在此我們已經調查出Os07g0456900與OsakαGal啟動子有強烈結合。藉由網路系統分析，我們發現Os07g0456900是屬於一個禾本科專一的NAC家族，並且是由10個同源基因組成。經由再葉子衰老和花發育期間表現量分析，我們發現Os07g0456900和一些同源基因轉錄因子的表現量在葉子衰老和花發育期間是上升的。最後我們藉由轉殖植物來調查基因機制，從基因抑制的轉殖植物中我們發現ZmUbiP::Os07g0456900-SRDX顯示成功抑制Os07g0456900和OsakαGal基因表達。這表明Os07g0456900可能參與OsakαGal基因在葉片衰老和花發育過程中。

Leaf senescence is the final stage of the developmental process that ultimately leads to organ death. This process is under the control of a genetically programmed sequence and is referred to as program cell death. Chloroplasts are the earliest organelles subjected to degradation during leaf senescence, and breakdown of Chlorophyll takes place when thylakoid membranes are disrupted. We have previously identified a senescence-associated gene, Os08g0495800 (OsakαGal), encoding a green plant specific alkaline a-galactosidase in rice. OsakαGal is a digalactosyldiacylglycerol (DGDG)-degrading enzyme associated with the disassembly of thylakoid membranes during chloroplast degradation. The aim of this work is to identify transcription factors that play putative function in the transactivation of OsakαGal gene. We have cloned upstream 1kb DNA sequences from start codon and used as bait for high-throughput yeast one-hybrid screening using a library composed of 1100 transcription factors from Oryza sativa cv. Nipponbare. We have identified Os07g0456900 strongly bind to the OsakαGal promoter. Phylogenetic analysis showed Os07g0456900 belongs to a novel grass-specific NAC subfamily consist of 10 homologous genes. The expression profiles of Os07g0456900 and some of the homologous gene transcripts were up-regulated during leaf senescence and flower development. Gene suppression transgenic plants ZmUbiP::Os07g0456900-SRDX showed successful down regulated Os07g0456900 and OsakαGal gene expression. This suggested that Os07g0456900 might involve in the transactivation of OsakαGal gene during leaf senescence and flower development.

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