Analysis of self‐repair mechanisms of Phaseolus vulgaris var. saxa using near‐infrared surface‐enhanced Raman spectroscopy

Abstract

We used surface-enhanced Raman spectroscopy (SERS) to investigate ultrastructural changes in cell-wall composition during the self-repair of lacerated hypocotyls of Phaseolus vulgaris var. saxa. A detailed study of self-repair mechanisms requires localized information about cell-wall structure and morphology in addition to the chemical cell-wall composition. Characteristic Raman and SER spectra yielded two-dimensional maps of cross sections of P. vulgaris var. saxa visualizing chemical compositions in the walls of different cell types and during various repair phases. SERS substrate particles were produced by the reduction of gold chloride on the plant tissue surface and characterized with absorption spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The SERS results were compared with stained cross sections of the same plant using dark-field microscopy with focus on lignin and suberin contents in repairing cells. In addition, SERS measurements revealed Au cyanide compounds on the cell surface, indicating the formation of hydrogen cyanide during the self-repair phase

Recent advances in linear and nonlinear Raman spectroscopy. Part V

“…Busch and coworkers used SERS to investigate ultrastructural changes in cell wall compounds during the self-repair of lacerated hypocotyls of Phaseolus vulgaris variety saxa. [51] The measurements revealed Au cyanide compounds on the cell surface, indicating the formation of hydrogen cyanide during the self-repair phase. Chiu et al carried out a study of the Raman band known as the 'spectroscopic signature of life' at 1602 cm À1 that sharply reflects the metabolic activity of cell mitochondria.…”

“…Busch and coworkers used SERS to investigate ultrastructural changes in cell wall compounds during the self‐repair of lacerated hypocotyls of Phaseolus vulgaris variety saxa . The measurements revealed Au cyanide compounds on the cell surface, indicating the formation of hydrogen cyanide during the self‐repair phase.…”

Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae Pv. phaseolicola

“…Ethylene production increases during infection and ETI which produces an equimolar amount of the toxin CN as a byproduct (García et al 2013). Liberation of CN from P. vulgaris leaves was also observed following wounding (Busch et al, 2010). However, the abundance of the nitrile β-cyanoalanine in the AWF was unexpected as this non-proteinogenic amino acid is only known to be formed from the combination of cysteine and CN in the plant mitochondria by β-cyanoalanine synthase, as the preferred route of CN detoxification in plants (García et al 2013).…”

Bioanalytical application of surface‐ and tip‐enhanced Raman spectroscopy

“…These advantages enabled the analysis of the structural changes in the cell wall composition during the self‐repair of Phaseolus vulgaris var. saxa . The SERS substrate was directly produced on the plant tissue surface by reduction of gold chloride and as a result, the formation of hydrogen cyanide in the wounded region was observed.…”