Facultad de Biología, Universidad Michoacana de San Nicolás de Hidalgo, Edificio R, Ciudad Universitaria, 58030, Morelia, Michoacán, México.
Laboratorio de Genómica Evolutiva, Unidad Académica de Ciencias Biológicas, Universidad Autónoma de Zacatecas, Campus II, 98066, Zacatecas, Zacatecas, México.
Biometals. 2021 Jun;34(3):603-620. doi: 10.1007/s10534-021-00299-9. Epub 2021 Mar 27.
As sessile organisms, plants respond to changing environments modulating their genetic expression, metabolism and postembryonic developmental program (PDP) to adapt. Among environmental stressor, lead (Pb) is one of the most hazardous pollutants which limits crop productivity. Here, we describe in detail the effects of a wide range of concentrations of Pb on growth and development and a possible convergence with phosphate (Pi) starvation response. We found that the response to Pb presents a biphasic curve dose response in biomass accumulation: below 400 µM show a stimulatory effect meanwhile at Pb doses up to 600 µM effects are inhibitory. We found that +Pb (800 µM) modifies root system architecture (RSA) and induces acidification media, according to in silico ion interaction, in the growing medium Pb and Pi coprecipitate and plants grow in both Pi deficiency and Pb stress at the same time, however in spite of seedlings are under Pi starvation AtPT2 expression are Pb downregulated indicating that in addition to Pi starvation stress, Pb regulates physiological responses in root system. Using the mutants stop1, lpr1/2 and lpi3, which are affected in Pi starvation response, we found that changes in RSA by +Pb is genetically regulated and there are shared pathways with Pi starvation response mediated by PDR2-LPR1/2 and LPI3 pathways since lpr1/2 and lpi3 mutants are insensitive to +Pb and Pi starvation. Taking together, these results indicate that similar changes in RSA induced by independent environmental stimuli +Pb and Pi starvation are due to similar mediated response by PDR2-LPR1/2 pathway.
作为固着生物，植物通过调节其基因表达、代谢和胚胎后发育程序（PDP）来适应不断变化的环境。在环境胁迫因素中，铅（Pb）是最危险的污染物之一，限制了作物的生产力。在这里，我们详细描述了广泛浓度的 Pb 对生长和发育的影响，以及与磷酸盐（Pi）饥饿反应的可能趋同。我们发现，对 Pb 的响应在生物量积累方面呈现出双相曲线剂量反应：低于 400 µM 时表现出刺激作用，而在 Pb 剂量高达 600 µM 时则表现出抑制作用。我们发现，+Pb（800 µM）会改变根系结构（RSA）并诱导介质酸化，根据离子相互作用的计算，在生长介质中，Pb 和 Pi 共沉淀，植物在同时存在 Pi 缺乏和 Pb 胁迫的情况下生长，然而，尽管幼苗处于 Pi 饥饿状态，但 AtPT2 的表达受到 Pb 的下调，表明除了 Pi 饥饿胁迫外，Pb 还调节根系的生理反应。使用受 Pi 饥饿反应影响的突变体 stop1、lpr1/2 和 lpi3，我们发现，+Pb 引起的 RSA 变化是遗传调控的，并且与由 PDR2-LPR1/2 和 LPI3 途径介导的 Pi 饥饿反应共享途径，因为 lpr1/2 和 lpi3 突变体对+Pb 和 Pi 饥饿不敏感。综上所述，这些结果表明，由独立环境刺激+Pb 和 Pi 饥饿引起的 RSA 相似变化是由于 PDR2-LPR1/2 途径介导的相似反应所致。
