However, luminescence in the red spectral domain (>640 nm) occurred first, then declined in parallel with the appearance of the emission in the blue-green (640 nm), peaking at 700–750 nm. In vitro oxidation of lipids induced luminescence throughout the visible spectrum (450–850 nm). We imaged this signal using a very sensitive cooled CCD camera and analysed its spectral characteristics using bandpass interference filters. This ultraweak endogenous chemiluminescence is linked to the oxidative metabolism, with lipid peroxidation constituting a major source of photons in plants. Plants, like most living organisms, spontaneously emit photons of visible light. The online version contains supplementary material available at 10.1007/s11734-x. Alternatively, the pathogen suppresses the host defense when the disease develops. These data indicated that disease manifestation is a simulated response of these defense molecules which can nullify the effect of the pathogen and its products, when resistance occurs. The transcription levels were mostly increased in the tolerant cultivar till 7 days post-infection (DPI), while downregulation of some of the genes were observed in the susceptible one. We monitored the gene expression levels of 12 important defense-related genes under in vivo condition. The results showed striking differences in the activity profile of these defense molecules through the course of the study. We further performed real-time nitric oxide (NO) detection studies. To understand the reasons behind such differential response, we investigated, in a time-dependent manner, biochemical activities of important defense enzymes, PR proteins, like peroxidase, polyphenol-oxidase, phenylalanine ammonia lyase, β-glucanase, chitinase, catalase, as well as phenols, flavonoids, chlorophyll and the key signaling molecule nitric oxide in their leaves. The study of morphological symptom development in two cultivars, Bullet, and Beldanga, showed very different disease expression pattern. Infection results in yield and marketability loss due to a decrease in the quality of fruits. Chloroplasts imaging was achieved with laser excitation at 543 nm and emission recorded at 655-755 nm.Ĭhili plants are affected by the hemibiotrophic ascomycota fungus Colletotrichum capsici causing Anthracnose. The fluorescence signal was visualized with an excitation (lex) and emission (lem) wavelengths of 488 nm and 505-605 nm respectively. The margins indicate the site of mechanical injury visualized under objective of of 20× (upper panel) and 40× (lower panel). The panels (from left to right) represents the Nomarski DIC (A, E) chl fluorescence (B, F) DHEox fluorescence (C, G) and combined (chl fluo + DHEox) (D, H) channel following 30 min of incubation in DHE in the presence of 0.01% DMSO. Superoxide anion radical imaging in cells of WT Arabidopsis leaves detected by confocal laser scanning microscope. (C) SOSG oxidation by 1 O 2 forming fluorescent SOSG-EP with excitation/emission maxima of ~504/525 nm). (B) SPY-LHP oxidation by LOOH forming SPY-LHPOx providing fluorescence with excitation/emission maxima of ~524/535 nm. − forming 2-OH-E + providing fluorescence with excitation/ emission maxima of ~500/590 nm.Principles of ROS detection and fluorochrome spectral properties (A) DHE oxidation by O 2 As a consequence, oxidation of biomolecules is induced, predominantly of polyunsaturated fatty acid, which leads to the formation of reactive intermediate products and electronically excited species. Based on fluorescence imaging, we provide experimental evidence that ROS are produced following wounding. In the current study, we focused on the production of reactive oxygen species (ROS) in wounded Arabidopsis leaves. Stress stimuli activate a plethora of early and late reactions, from electric signals induced within seconds upon injury, oxidative burst within minutes, and slightly slower changes in hormone levels or expression of defense-related genes, to later cell wall reinforcement by polysaccharides deposition, or accumulation of proteinase inhibitors and hydrolytic enzymes. within or in the close vicinity of affected tissue, or systemic, i.e.
Subsequent defense responses are either local, i.e.
Mechanical injury or wounding in plants can be attributed to abiotic or/and biotic causes.
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