Della Rovere Federica, Fernando Malimage Sara Anupama, D'Angeli Simone, Peduzzi Alice, Piacentini Diego, Altamura Maria Maddalena, Falasca Giuseppina
Department of Environmental Biology, Sapienza University of Rome, Rome 00185, Italy.
Department of Environmental Biology, Sapienza University of Rome, Rome 00185, Italy.
Plant Sci. 2025 Oct;359:112625. doi: 10.1016/j.plantsci.2025.112625. Epub 2025 Jun 23.
Arsenic, a toxic metalloid, predominantly exists in soil as inorganic arsenate (As) and arsenite (As). Upon root uptake, As is extensively reduced to As in the plant. The Arabidopsis root system comprises primary, lateral and adventitious roots. It is unclear whether the inorganic arsenic-form and concentration affect specific components of the Arabidopsis root system. Synergistic and antagonistic interactions of brassinosteroids and jasmonates regulate plant development under stress, as shown by treatments with epibrassinolide (eBL) or methyl jasmonate (MeJA). However, the role of these phytohormones in root response to inorganic arsenic has been poorly studied. This research aimed to determine whether Arabidopsis roots of different type respond similarly or differently to As and As, administered as NaAsO and NaHAsO·7 HO respectively, and whether these responses are modulated by the application of eBL and/or MeJA. The results demonstrated that As inhibited primary root elongation, in contrast to As, but promoted lateral and adventitious root formation, especially when combined with eBL. As, more than As, induced irregular cell divisions in the quiescent center and the stem cell niche of root apices, mainly of lateral roots. The As negative impact on lateral/adventitious roots was counteracted by eBL which favoured root formation. Xylogenesis was induced by periclinal divisions in the pericycle of the basal hypocotyl and was promoted by MeJA as a mechanical defense barrier against As. Collectively, results suggest that Arabidopsis responds to As by strengthening its root system and applications of eBL and MeJA ameliorate root development in specific ways, depending on the As-form.
砷是一种有毒类金属，主要以无机砷酸盐（As）和亚砷酸盐（As）的形式存在于土壤中。被根系吸收后，砷在植物体内会大量还原为亚砷酸盐。拟南芥根系由主根、侧根和不定根组成。目前尚不清楚无机砷的形态和浓度是否会影响拟南芥根系的特定组成部分。正如用表油菜素内酯（eBL）或茉莉酸甲酯（MeJA）处理所表明的那样，油菜素类固醇和茉莉酸酯的协同和拮抗相互作用在胁迫下调节植物发育。然而，这些植物激素在根系对无机砷的反应中的作用尚未得到充分研究。本研究旨在确定不同类型的拟南芥根系对分别以NaAsO和NaHAsO·7 HO形式施用的As和As的反应是否相似或不同，以及这些反应是否会受到eBL和/或MeJA施用的调节。结果表明，与As相反，As抑制主根伸长，但促进侧根和不定根的形成，尤其是与eBL结合时。与As相比，As更能诱导根尖静止中心和干细胞龛中的不规则细胞分裂，主要是侧根的根尖。eBL对侧根/不定根的负面影响被有利于根系形成的eBL抵消。木质部形成是由基部下胚轴中柱鞘的平周分裂诱导的，并且MeJA作为对As的机械防御屏障促进了木质部形成。总体而言，结果表明拟南芥通过强化其根系来响应As，并且eBL和MeJA的施用根据As的形态以特定方式改善根系发育。
