Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Jagiellońska 28, PL-40032 Katowice, Poland.
Int J Mol Sci. 2021 May 9;22(9):5017. doi: 10.3390/ijms22095017.
The fungal toxin fusicoccin (FC) induces rapid cell elongation, proton extrusion and plasma membrane hyperpolarization in maize coleoptile cells. Here, these three parameters were simultaneously measured using non-abraded and non-peeled segments with the incubation medium having access to their lumen. The dose-response curve for the FC-induced growth was sigmoidal shaped with the maximum at 10 M over 10 h. The amplitudes of the rapid growth and proton extrusion were significantly higher for FC than those for indole-3-acetic acid (IAA). The differences between the membrane potential changes that were observed in the presence of FC and IAA relate to the permanent membrane hyperpolarization for FC and transient hyperpolarization for IAA. It was also found that the lag times of the rapid growth, proton extrusion and membrane hyperpolarization were shorter for FC compared to IAA. At 30 °C, the biphasic kinetics of the IAA-induced growth rate could be changed into a monophasic (parabolic) one, which is characteristic for FC-induced rapid growth. It has been suggested that the rates of the initial phase of the FC- and IAA-induced growth involve two common mechanisms that consist of the proton pumps and potassium channels whose contribution to the action of both effectors on the rapid growth is different.
真菌毒素 fusicoccin (FC) 可诱导玉米胚芽鞘细胞快速伸长、质子外排和质膜超极化。在这里，使用未经磨损和去皮的段来同时测量这三个参数，并使孵育介质能够进入其内腔。FC 诱导生长的剂量反应曲线呈 S 形，在 10 h 内最大浓度为 10 M。FC 诱导的快速生长和质子外排的幅度明显高于吲哚-3-乙酸 (IAA)。在存在 FC 和 IAA 的情况下观察到的膜电位变化之间的差异与 FC 的永久性膜超极化和 IAA 的瞬时超极化有关。还发现，与 IAA 相比，FC 引起的快速生长、质子外排和膜超极化的滞后时间更短。在 30°C 下，IAA 诱导的生长速率的两相动力学可以转变为单相（抛物线）动力学，这是 FC 诱导的快速生长的特征。有人提出，FC 和 IAA 诱导生长的初始阶段的速率涉及两种共同的机制，包括质子泵和钾通道，它们对两种效应物对快速生长的作用的贡献不同。
