Microbiosensor And Its Application On The Transgenic Plant Physiological Process In Real Time

It is crucially important to know the change of signal molecules in plant physiological and pathologic process in plant protecting, insect and fungal pathogen avoiding, plant growth promoting and plant research.Oxalic acid (OA), a non-host-specific toxin secreted by Sclerotinia sclerotiorum during pathogenesis, has been demonstrated to be a major phytotoxic and pathogenicity factor. Oxalate oxidase (OXO) is an enzyme for detoxification of oxalic acid. Therefore, the introduction of OXO gene into oilseed rape (Brassica napus L.) to break down OA may be an alternative way of increasing the plant's resistance to S. sclerotiorum.Oxidative burst is defined as a rapid and transient production of large amounts of reactive oxygen species (ROS), including superoxide anion O2-, hydrogen peroxide (H₂O₂), and hydroxyl radical (OH*), possibly.In order to investigate the activation of OXO in transgenic oilseed rape, a convenient and available method was used to monitor changes in pH in response to stress induced by OA. The pH sensor, a platinum microcylinder electrode modified using polyaniline film, exhibited a linear response between the pH range of 3 and 7, with a Nernst response slope of 70 mV/pH at room temperature. The linear correlation coefficient was 0.9979. Changes induced by OA in the pH of leaf tissue of different species of oilseed rape were monitored in real time in vivo using this electrode. The results clearly showed that the transgenic oilseed rape was more resistant to OA than the nontransgenic oilseed rape.A rapid and simple technique based on electrochemical-modified electrode was employed for in vivo detection of oxidative burst in oilseed rape (Brassica napus L.) leaves.The Platinum (Pt) micro-particles dispersed Pt electrode modified with poly (o-phenylenediamine) film exhibited high sensitivity, selectivity and stability in H₂O₂ detection. Chronoamperometry was used to obtain satisfactory linear relations between reductive current intensities and H₂O₂ concentrations at the potential of -0.1 V in different electrolytes. This electrode was used to detect oxidative burst in oilseed rape against fungal pathogen in vivo. The results showed that the oxidative bursts induced by infection of fungal pathogen Sclerotinia sclerotiorum (lib) de Bary exhibited notable different mechanisms between susceptible genotype and glucose oxidase (GO)-transgenic oilseed rape.This H₂O₂ electrode was used to detect oxidative burst in oilseed rape against salicylic acid (SA) and benro(l,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH) both in susceptible genotype and glucose oxidase (GO)-transgenic oilseed rape. The research showed that, after induced by elicitor active substances, the oxygen bursts exhibited entirely different characteristic depend on elicitors and varieties of oilseed rape.