Devlin W S, Gustine D L
Department of Agronomy and Graduate Program of Plant Physiology, The Pennsylvania State University, University Park, Pennsylvania 16802.
Plant Physiol. 1992 Nov;100(3):1189-95. doi: 10.1104/pp.100.3.1189.
The role of the oxidative burst, transient production of activated oxygen species such as H(2)O(2) and superoxide (O(2) (-)) in elicitation of phytoalexins and the hypersensitive reaction (HR) was investigated in white clover (Trifolium repens L.) and tobacco (Nicotiana tabacum L.). H(2)O(2) and O(2) (-) production was measured as chemiluminescence (CL) mediated by luminol, which was added to suspension-cultured white clover just before measurement in an out-of-coincidence mode scintillation counter. Maximum CL occurred between 10 and 20 min after addition of 0.4 x 10(8) colony-forming units/mL of incompatible Pseudomonas corrugata or 158 mum HgCl(2). Autoclaved P. corrugata produced a slightly higher response. Elicitation of cells with 25 mum HgCl(2) did not produce CL. Preincubation of plant cells in superoxide dismutase, which converts O(2) (-) to H(2)O(2), for 2 min before addition of bacteria did not significantly increase maximum CL levels (P >/= 0.05). Preincubation of plant cells with catalase for 2 min before addition of bacteria prevented the increase in CL, confirming that H(2)O(2) is the substrate for the luminol reaction. Addition of live bacteria or HgCl(2) (25 and 158 mum) to white clover increased levels of the phytoalexin medicarpin during a 24-h period, but addition of autoclaved bacteria did not elicit formation of medicarpin. Preincubation of plant cells with catalase, which quenched the bacteria-induced oxidative burst, did not decrease phytoalexin accumulation. Live bacteria infiltrated into Havana 44 tobacco leaf panels induced development of the HR, but autoclaved bacteria did not. Incubation of live bacteria with superoxide dismutase and catalase before infiltration into tobacco leaves did not interfere with development of the HR. Tobacco leaf panels infiltrated with up to 158 mum HgCl(2) did not develop an HR. These results suggest that an oxidative burst consisting of H(2)O(2) and O(2) (-) does occur during these two plant defense responses, but it may not be a necessary element of the signaling system for HR and phytoalexin formation.
在白三叶草（Trifolium repens L.）和烟草（Nicotiana tabacum L.）中研究了氧化爆发（即诸如过氧化氢（H₂O₂）和超氧阴离子（O₂⁻）等活性氧的短暂产生）在植物抗毒素诱导和过敏反应（HR）中的作用。通过鲁米诺介导的化学发光（CL）来测量H₂O₂和O₂⁻的产生，在测量前将鲁米诺以非符合模式闪烁计数器的方式添加到悬浮培养的白三叶草中。在添加0.4×10⁸个菌落形成单位/毫升的不亲和的皱叶假单胞菌或158 μmol HgCl₂后10至20分钟出现最大CL。高压灭菌的皱叶假单胞菌产生的反应略高。用25 μmol HgCl₂诱导细胞未产生CL。在添加细菌前将植物细胞在超氧化物歧化酶（将O₂⁻转化为H₂O₂）中预孵育2分钟，并未显著提高最大CL水平（P≥0.05）。在添加细菌前将植物细胞用过氧化氢酶预孵育2分钟可阻止CL的增加，证实H₂O₂是鲁米诺反应的底物。向白三叶草中添加活细菌或HgCl₂（25和158 μmol）在24小时内增加了植物抗毒素苜蓿素的水平，但添加高压灭菌的细菌未诱导苜蓿素的形成。用过氧化氢酶预孵育植物细胞（可淬灭细菌诱导的氧化爆发）并未降低植物抗毒素的积累。将活细菌渗入哈瓦那44烟草叶片组织诱导了HR的发展，但高压灭菌的细菌则未诱导。在渗入烟草叶片前将活细菌与超氧化物歧化酶和过氧化氢酶一起孵育并不干扰HR的发展。用高达158 μmol HgCl₂渗入的烟草叶片组织未发展出HR。这些结果表明，在这两种植物防御反应过程中确实会发生由H₂O₂和O₂⁻组成的氧化爆发，但它可能不是HR和植物抗毒素形成信号系统的必要元素。
