Fraudentali Ilaria, Pedalino Chiara, D'Incà Riccardo, Tavladoraki Paraskevi, Angelini Riccardo, Cona Alessandra
Department of Science, University Roma Tre, Rome, Italy.
Istituto Nazionale Biostrutture e Biosistemi (INBB), Rome, Italy.
Front Plant Sci. 2023 Apr 21;14:1154431. doi: 10.3389/fpls.2023.1154431. eCollection 2023.
Polyamines (PAs) are ubiquitous low-molecular-weight aliphatic compounds present in all living organisms and essential for cell growth and differentiation. The developmentally regulated and stress-induced copper amine oxidases (CuAOs) oxidize PAs to aminoaldehydes producing hydrogen peroxide (HO) and ammonia. The CuAOβ (AtCuAOβ) was previously reported to be involved in stomatal closure and early root protoxylem differentiation induced by the wound-signal MeJA apoplastic HO production, suggesting a role of this enzyme in water balance, by modulating xylem-dependent water supply and stomata-dependent water loss under stress conditions. Furthermore, AtCuAOβ has been shown to mediate early differentiation of root protoxylem induced by leaf wounding, which suggests a whole-plant systemic coordination of water supply and loss through stress-induced stomatal responses and root protoxylem phenotypic plasticity. Among apoplastic ROS generators, the D isoform of the respiratory burst oxidase homolog (RBOH) has been shown to be involved in stress-mediated modulation of stomatal closure as well. In the present study, the specific role of AtCuAOβ and RBOHD in local and systemic perception of leaf and root wounding that triggers stomatal closure was investigated at both injury and distal sites exploiting and insertional mutants. Data evidenced that AtCuAOβ-driven HO production mediates both local and systemic leaf-to-leaf and root-to-leaf responses in relation to stomatal movement, mutants being completely unresponsive to leaf or root wounding. Instead, RBOHD-driven ROS production contributes only to systemic leaf-to-leaf and root-to-leaf stomatal closure, with mutants showing partial unresponsiveness in distal, but not local, responses. Overall, data herein reported allow us to hypothesize that RBOHD may act downstream of and cooperate with AtCuAOβ in inducing the oxidative burst that leads to systemic wound-triggered stomatal closure.
多胺（PAs）是普遍存在于所有生物体内的低分子量脂肪族化合物，对细胞生长和分化至关重要。发育调控和应激诱导的铜胺氧化酶（CuAOs）将多胺氧化为氨基醛，产生过氧化氢（HO）和氨。先前报道CuAOβ（AtCuAOβ）参与伤口信号茉莉酸甲酯（MeJA）诱导的气孔关闭和早期根原生木质部分化以及质外体HO的产生，这表明该酶在水分平衡中发挥作用，即在胁迫条件下通过调节依赖木质部的水分供应和依赖气孔的水分损失来实现。此外，AtCuAOβ已被证明介导叶片损伤诱导的根原生木质部早期分化，这表明通过胁迫诱导的气孔反应和根原生木质部表型可塑性实现了全株范围内水分供应和损失的系统协调。在质外体活性氧产生剂中，呼吸爆发氧化酶同源物（RBOH）的D亚型也已被证明参与胁迫介导的气孔关闭调节。在本研究中，利用T-DNA插入突变体，在损伤部位和远端部位研究了AtCuAOβ和RBOHD在触发气孔关闭的叶片和根部伤口的局部和系统感知中的具体作用。数据表明，AtCuAOβ驱动的HO产生介导了与气孔运动相关的局部和系统的叶对叶和根对叶反应，AtCuAOβ突变体对叶片或根部伤口完全无反应。相反，RBOHD驱动的活性氧产生仅有助于系统的叶对叶和根对叶气孔关闭，RBOHD突变体在远端而非局部反应中表现出部分无反应。总体而言，本文报道的数据使我们能够推测，RBOHD可能在诱导导致系统伤口触发气孔关闭的氧化爆发中作用于AtCuAOβ的下游并与其合作。
