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Auxin Signaling-Mediated Apoplastic pH Modification Functions in Petal Conical Cell Shaping
First author: Xie Dang; Affiliations: Fujian Agriculture and Forestry University (福建農林大學): Fuzhou, China
Corresponding author: Deshu Lin
The flowers of angiosperm species typically contain specialized conical cells. Although substantial progress has been achieved regarding the mechanisms underlying flower development, little is known about how petal cells achieve final conical shape. Here, we use 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) as a fluorescent pH indicator for analyzing the apoplastic pH of conical cells in Arabidopsis and show that normal conical cell expansion requires auxin signaling and apoplastic pH changes. By combining imaging analysis and genetic and pharmacological experiments, we demonstrate that apoplastic acidification and alkalization correlate with an increase and decrease in tip sharpening of conical cells, respectively. Initial expansion of conical cells is accompanied by decreased apoplastic pH, which is associated with increased auxin signaling. Decreased auxin levels, transport, or signaling abolishes cell wall acidification and causes reduced tip sharpening and heights of conical cells. These findings provide an insight into apoplastic pH regulation of conical cell expansion.
被子植物物種的花通常具有特化的錐形細胞。儘管關於花發育相關的研究已經取得了巨大的進展,但是關於花瓣上的錐形細胞如何獲取其最終的錐形形態還不清楚。本文中,作者利用8-羥基芘-1,3,6-三磺酸三鈉鹽(HPTS)作為螢光pH指示劑來分析擬南芥花瓣上錐形細胞中質外pH值,發現正常的錐形細胞擴張需要生長素信號以及質外pH值的改變。通過結合呈像分析以及遺傳和藥理學實驗,作者發現質外酸化和鹼化分別與錐形細胞尖端銳化程度的增加和減少有關。圓錐細胞最初的擴張伴隨著質外pH值的降低,而這與生長素信號的增強有所關聯。生長素含量、轉運以及信號轉導水平的降低均能夠使得細胞壁不再酸化,從而降低錐形細胞尖端的銳化程度和高度。本文的研究發現為植物花瓣上錐形細胞擴張的質外pH值調控提供了新的視野。
p.s. 質外體(apoplast),是指植物細胞原生質體外圍由細胞壁、胞間隙和導管組成的系統。
錐形細胞,是被子植物花瓣上的一個特化結構,能夠為昆蟲授粉提供一個穩定的「著陸平臺」。
酸生長理論,生長素通過激活細胞膜上的H+ATPase,將胞內的H+泵到胞外,使得細胞壁pH值降低、酸化,從而促進細胞壁鬆弛,最終導致細胞的擴張。
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通訊:林德書 (http://net.fafu.edu.cn/hist/15/40/c5708a136512/page.htm)
個人簡介:2000-2004年,福建農林大學,學士;2004-2007年,福建農林大學,碩士;2007-2012年,中國農業大學,博士;2009-2011年,美國加州大學河濱分校,聯合培養;2012-2014年, 中科院植物逆境生物學研究中心,博士後;2012-2013年,美國加州大學河濱分校,訪問學者;2014年-至今,福建農林大學,教授。
研究方向:1.花瓣器官形態建成;2. 花瓣錐形細胞形態建成;3. 細胞骨架蛋白在水稻、甘蔗等農作物中的功能研究。
doi: https://doi.org/10.1016/j.celrep.2020.02.087
Journal: Cell Reports
Published date: March 17, 2020