Effect related analysis of herbicides
Current and global developments present new challenges for the current plant breeding and plant production that can only be approached by innovative solutions and by concentration of expertise coming even outside from classical cooperation networks.
In order to protect the food production, intensive agriculture is inseparable from the use of herbicides. Due to the global energy shortage and hence the increased interest in plants as regrowing energy source, the focus lies on always shorter generation cycles of the cultured plant as well as an increased yield. This would result in a further enhanced use of herbicides. Since 1960 it is known that the effect of the most efficient and therefore most successful herbicides is attributed to the interference with the photosystem II (PSII). These inhibiting substances are called PSII inhibitors. Including more than 52 derivates, still today the PSII inhibitors represent the biggest class of herbicides. However, the success of these PSII herbicides is reflected after decades of intensive applications in the accumulation within the environment.
Source: Ferreira, K.N. et al. (2004) Science 303, p.1831-1838
Intense efforts to sustain a lasting application of the herbicides, implies knowledge about their impact in the matrices and the environment. In consequence, only then it is possible to limit the amount, to control, to abolish or even to completely prohibit the holding. The various techniques applied to date to monitor herbicides in environmental and food samples are based on cost intensive and very complex chromatographic and spectrometric analyses. For the detection of several numbers of toxic compounds, each analyte needs an individual standard (compound related analysis).
When understanding the molecular effect of the PSII herbicides on the PSII process or the PSII structures could also apply the bionic principle of detection. Their implementation would represent an interactive procedure of detection resulting in a “single-batch” acquisition of whole classes of PSII herbicides (effect related analysis).In this way, the cost intensive investigations can be limited by performing analyses only on those matrices that contain a positive risk potential. Therefore, the aim of this research is to gain a deep understanding about the principle of the molecular interactions between the subunits of the plant’s photosystem II (PSII) and its ligands under extracellular conditions. Furthermore, based on these interactions an effect related ‘single-batch’ detection of a whole class of PSII herbicides should be developed. In order to visualize and quantify these molecular interactions labelfree, a highly sensitive optical biosensor platform based on microsystemic, integrated optical MACH-Zehnder-Interferometer (IO-MZI) will be generated. The bionic implementation via IO_MZI of the molecular recognition structures with identical effect modeled based on PSII cofactors and their binding pocket should be used to demonstrate the acquisition of PSII herbicides by the competitive principle of mechanism.