狗尾草SvMYB117之基因功能研究

Abstract

典型C4型植物在克蘭茲解剖構造的協助下，執行光合作用的效能比C3植物更有效率。由於根部著名的SHR-SCR發育調控在玉米的葉片中也存在著，玉米地上部的克蘭茲解剖構造被認定是根部型態的延伸構型。李文雄院士實驗室已進行一系列的生資分析，包含著基因共表達網絡的建立以及啟動子上順式作用元件的找尋。結果顯示，SvMYB117被預測可能為SvSHR1的上游調控者，並且其他可能受到SvMYB117所調控的下游轉錄因子也被找出。 在本研究中，我們嘗試在同樣是C4型的狗尾草中，查看在玉米中所預測的MYB117-SHR1的調控機制是不是也存在著。SvMYB117在狗尾草中有三種不同選擇性剪切成的成熟mRNA，並且有較高表現在快速分裂的組織中，例如發育中的葉片、分生組織及分蘗。利用我們所建立的狗尾草葉片原生質體短暫表現系統發現，SvMYB117可能透過在細胞核中調控SvANT1及SvbHLH63的方式參與在器官發育的過程中。然而，因為SvSHR1表現量的不穩定趨勢，是否會受到SvMYB117所調控則還需要更多實驗來驗證。因此在本研究中，透過我們所建立的狗尾草葉片原生質體短暫表現系統，發現到SvMYB117極有可能藉由調控SvANT1的方式影響著狗尾草的器官發育。

Superior to the C3-type, the C4-type plants drive photosynthesis efficiently with the support of Kranz anatomy. In maize, Kranz anatomy is an extension of root architecture. The well-known SHR-SCR regulatory pathway in root also involves in maize Kranz anatomy development. Based on the co-expression data and the prediction of cis elements from laboratory of Dr. Wen-Hsiung Li, ZmMYB117 was identified to be the possible upstream regulator of ZmSHR1. Several other possible target genes of ZmMYB117 had been predicted. We attempted to verify whether the possible MYB117-SHR1 regulatory pathway also existed in another novel C4 plant, Setaria viridis. SvMYB117 had three alternative splicing forms and highly expressed in strongly dividing tissues, including developing leaves, meristems, and tillers. Through S. viridis protoplast transient system we established, SvMYB117 might involve in organogenesis process through regulating SvANT1 and SvbHLH63 in nucleus. However, due to the unstable expression tendency of SvSHR1 in our condition, advanced experiments are necessary to reveal whether SvMYB117-SvSHR1 regulatory pathway do exist in S. viridis developmental process. In this study, protoplast transient system of S. viridis leaf blade was successfully established. We found that SvMYB117 might involve in organogenesis process through regulating SvANT1.