阿拉伯芥轉錄因子B-box domain protein 14參與光以及茉莉酸訊息傳遞路徑中的功能性研究

Abstract

光和植物激素茉莉酸 (jasmonates) 協同調控植物的生長和發育，涉及許多在這些途徑之中進行相互作用的基因。其中FIN219（FAR-RED INSENSITIVE 219）在這兩條途徑中已有廣泛研究。通過對比在遠紅光（FR）下和有或無甲基化茉莉酸（MeJA）處理下的糖皮質激素誘導的 PGRFIN219（glucocorticoid-inducible FIN219），幼苗與 Col-0 的微陣列數據分析顯示，PGRFIN219 中的 BBX14 基因表現低於 Col-0，這暗示 FIN219 與 BBX14（B-BOX protein 14）之間可能存在潛在關係。然而BBX14 在光和 JA 信號途徑中的作用尚未被了解，而且HY5（ELONGATED HYPOCOTYL 5）和 COP1（CONSTITUTIVE PHOTOMORPHOGENIC 1） 也在光信號途徑中扮演關鍵角色。定量即時聚合酶鏈鎖反應分析（qPCR）顯示，FIN219 和 HY5 都影響 BBX14 的表現，同樣的BBX14 也影響 FIN219 和 HY5 的表現。進一步的雙分子螢光互補（BiFC）分析顯示，BBX14 與 FIN219 及 HY5 之間存在相互作用，但未觀察到 BBX14 與 COP1 之間的相互作用。我們發現 MeJA 誘導的 BBX14 在黑暗條件下調控下胚軸長度；另外，BBX14 的過表現會在 FR 光下抑制 HY5 的功能。COP1 也位於 BBX14 的下游來調控下胚軸延長。總體而言，這些結果表明 FIN219、HY5 和 BBX14 可能是反饋迴路的一部分，並參與 JA 信號途徑中的其他機制，我們的研究發現顯示 BBX14 可能涉及光和 JA 信號途徑，以調控幼苗下胚軸的延長。

Light and plant hormone jasmonates (JA) coordinately regulate plant growth and development, involving numerous genes that participate in the crosstalk between these pathways. For example, FIN219 (FAR-RED INSENSITIVE 219) has been extensively studied in both pathways. Analysis of microarray data by comparing PGRFIN219 (an inducible FIN219 overexpression line) seedlings with Col-0 under far-red (FR) light with or without methyl JA (MeJA) treatment revealed lower expression of the BBX14 (B-BOX protein 14) gene in PGRFIN219 versus Col-0, suggesting a potential relationship between FIN219 and BBX14. However, the role of BBX14 in light and JA signaling pathways remains unexplored. Additionally, HY5 (ELONGATED HYPOCOTYL 5) and COP1 (CONSTITUTIVE PHOTOMORPHOGENIC 1) play crucial roles in light signaling pathway. Quantitative real-time PCR analysis shows that both FIN219 and HY5 affect BBX14 expression. Similarly, BBX14 also affects the expression of FIN219 and HY5. Further BiFC assays demonstrated the interaction between BBX14 and FIN219, as well as HY5, but no interaction between BBX14 and COP1 was observed. Furthermore, we found that BBX14 induction by MeJA regulates hypocotyl length under the dark conditions. Our results indicate that BBX14 overexpression results in a suppression of HY5 function under FR light. COP1 is also in the downstream of BBX14 in regulating hypocotyl elongation. The feedback regulation between FIN219 and BBX14 influences the sensitivity of BBX14 response to MeJA in Arabidopsis. Overall, these results suggest that FIN219, HY5, and BBX14 may be part of a feedback loop and involved in other mechanisms in the JA signaling pathway. Our findings indicate that BBX14 is likely involved in both light and JA signaling pathways.