RAV家族的轉錄因子被歸類為植物特異性的 AP2/EREBP (APETALA2) 超家族的成員，蛋白質結構具有兩個 DNA 結合域。它們的功能涉及多個領域，例如調控植物發育以及對病原體感染或者其他非生物脅迫的防禦反應。蘭科植物是開花植物中的一大家族，其種類約佔了被子植物的10%。它們包含超過29,000個物種，是最多樣、分布最廣闊的被子植物之一，並幾乎可以在地球上的所有棲息地中找到。蘭科包括5個亞科，包括Apostasioideae、 Vanilloideae、 Cypripedioideae、 Orchidoideae和Epiendroideae，並以其獨特的花形態和生殖生物學而著稱。雖然過去已有在其他植物中探討RAV基因的相關研究，但它們在蘭花所扮演的角色尚未有相關的研究。
首先，從OrchidBase中檢索到2段RAV的序列，分別命名為PeRAV1 和 PeRAV2並將其與擬南芥和水稻的RAV序列進行比對。我們發現蝴蝶蘭 PeRAV1 和 PeRAV2 與其他物種的RAV基因序列，特別是AP2和B3兩個DNA 結合域非常相似，尤其是。此外，為了探究蘭科植物RAV基因之間的進化關係，從NCBI中收集了雙子葉植物和單子葉植物的RAV蛋白質序列進行分析，並構建了系統發育樹。PeRAV1及PeRAV2以及蘭科植物的RAV蛋白質形成單系類群。在時間及空間表現模式分析結果，PeRAVs主要在花和葉中表達，並且PeRAV2的表現量比PeRAV1的表現量多出近10倍，推測蝴蝶蘭PeRAV2的功能可能比PeRAV1更重要。酵母菌雙雜交分析結果顯示，PeRAV1有能力和PeRAV2形成異源雙聚體，但兩者都無法形成同源雙聚體。分別大量表達PeRAV1以及PeRAV2在擬南芥，和野生型植株比較發現延遲開花時間。然而，分別大量表達PeRAV1-SRDX以及PeRAV2-SRDX在擬南芥則可以促進擬南芥開花。進一步以病毒誘導基因靜默(Virus-induced gene silencing)功能分析，發現被靜默的植株比對照組開花時間快，顯示蝴蝶蘭的開花時間明顯受到延遲。綜合以上，PeRAV1及PeRAV2以異源雙聚體具有調控蝴蝶蘭開花的功能。

Transcription factors of the RAV (RELATED TO ABI3 AND VP1) family are classified as members of the AP2/EREBP (APETALA2) superfamily. They are plant-specific and possess two DNA-binding domains(AP2、B3). They are involved in multiple functions such as different aspects of plant development and response to pathogen infections and abiotic stresses.
Orchidaceae is the family with the largest number of species, accounting for about 10% of angiosperms. They contain more than 29,000 species and can be found in almost all habitats on earth. Orchidaceae includes five subfamilies, namely Apostasioideae, Vanilloideae, Cypripedioideae, Orchidoideae and Epiendroideae. They are is known for unique flower morphology and reproductive biology. Although RAV genes have been studied in many other plants, their characteristics in orchids have not yet been addressed.
Two of RAV genes, PeRAV1 and PeRAV2, were identified and retrieved from OrchidBase and compared them with those of Arabidopsis and rice. BothPeRAV1 and PeRAV2 have two DNA-binding domains and are homologous to the sequences of RAVs in other plant species. Phylogenetic analysis results showed that PeRAVs could form a monophyletic relationship with other orchid RAVs. Spatial and temporal gene expression analysis results indicated that PeRAVs are mainly expressed in flowers and leaves, and the expression level of PeRAV2 was much about 10-fold than that of PeRAV1, suggesting that PeRAV2 might be more important. PeRAV1 and PeRAV2 formed heterodimers in yeast two-hybrid analysis, but either of them could not respectively form homodimer. Ectopically overexpression of PeRAV1 or PeRAV2 in Arabidopsis showed that the flowering time was prolonged compared to that of wild type. However, respective overexpression of PeRAV1- and PeRAV2-SRDX showed opposite phenotypes of promoting flowering as compared to that of overexpression of PeRAVs. Furthermore, virus-induced gene silencing (VIGS) of PeRAVs in Pahalenopsis showed delayed flowering. Together, the PeRAVs were involved in delayed flowering.

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