[O2-* burst of tobacco leaves triggered by Erwinia carotovora subsp. carotovora inoculation].
O(-.)(2) production based on chemical method by Ecc-treated intact tobacco leaves was observed. It showed a long-lasting one-phase course beginning 1 h and ending 14 h after Erwinia carotovora subsp. carotovora (Ecc) was inoculated. In Ecc-treated leaves, O(-.)(2) production rate of 3 h is 2 times of 1 h, and of 10 h it remains 1.7 times. It decreases rapidly between 10 h and 14 h, at 14 h it falls to the level before inoculation. This is a completely different course from the widely accepted two-phase course obtained from suspension-cultured cells. Electron spin resonance (ESR) spectrum of O(-.)(2) produced by intact tobacco leaves after Ecc inoculation 2 h and 6 h was also observed, the amplitude of 6 h is larger than of 2 h in Ecc-treated group. In the control group, there is no difference between the amplitude of 2 h and 6 h. This indicated that O(-.)(2) amount of Ecc-treated group is higher than of the control group, which is the same result as obtained through chemical method. The ESR spectrum of O(-.)(2) produced by chloroplasts and mitochondria from tobacco leaves after 2 h and 6 h after Ecc inoculation were observed. In chloroplast experiment, the amplitude of 6 h was larger than of 2 h in Ecc-treated group while it was the same in the control group. ESR spectrum of O(-.)(2) produced by mitochondria was proved to be a same result after a careful comparison, in spite of a greater difference between 2 h and 6 h in control group than chloroplast experiment. The fact that spectra of these two organelles were both synchronous with that of intact leaves implied that these two organelles possibly participated in cellular O(-.)(2) burst. Chloroplasts in the dark showed no ESR spectrum 2 h and 6 h after Ecc inoculation in Ecc-treated group as well as in the control group, indicating that O(-.)(2) in the chloroplast probably originated from the photosynthetic electron transport process.
Duan
Jian-Gong
JG
School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Li
Hong-Yu
HY
Ru
Yi
Y
Liang
Hou-Guo
HG
Wang
Jin-Sheng
JS
Li
Min-Quan
MQ
Yang
Fu-Jun
FJ
D002736:Chloroplasts / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D054884:Host-Pathogen Interactions; D008928:Mitochondria / Q000378:metabolism; D016973:Pectobacterium carotovorum / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014026:Nicotiana / Q000378:metabolism / Q000382:microbiology*
D017382:Reactive Oxygen Species