Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, China.
Basic Forestry and Proteomic Research Center, Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Cell Rep. 2020 Mar 17;30(11):3904-3916.e3. doi: 10.1016/j.celrep.2020.02.087.
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.
被子植物的花通常含有特化的圆锥形细胞。尽管在花发育的机制方面已经取得了相当大的进展，但对于花瓣细胞如何达到最终的圆锥形仍知之甚少。在这里，我们使用 8-羟基芘-1,3,6-三磺酸三钠盐（HPTS）作为荧光 pH 指示剂来分析拟南芥中圆锥形细胞的质外体 pH，并表明正常的圆锥形细胞扩展需要生长素信号和质外体 pH 的变化。通过结合成像分析以及遗传和药理学实验，我们证明质外体酸化和碱化分别与圆锥形细胞尖端变锐度的增加和减少相关。圆锥形细胞的初始扩展伴随着质外体 pH 的降低，这与生长素信号的增加有关。生长素水平、运输或信号的降低会抑制细胞壁酸化，并导致尖端变锐度和圆锥形细胞高度降低。这些发现为质外体 pH 对圆锥形细胞扩展的调节提供了深入的了解。
