Morphological and Proteomic Evaluation of Zea Mays in Response to Osmotic Stress

Introduction: Drought is the main abiotic stress responsible for crop loss worldwide. Maize (Zea mays L.) is a widely grown drought-sensitive crop used as a staple food by the growing population. Therefore, it is imperative to assess the molecular mechanisms behind drought response and tolerance in maize. Transcriptomic profiling of abiotic stress responsive pathways in various crops appeared to be an unreliable approach due to post-transcriptional modifications, while there is limited published data on molecular mechanisms of osmotic-stress response in maize. Hence our study aimed at profiling osmotic stress responsive proteins augmented by their associated morphological features in Z. mays. Materials and Methods: In this regard, morphological and proteomic investigations were carried out on 16-day maize seedlings exposed to 5% (w/v) and 10% (w/v) polyethylene glycol(PEG) to induce osmotic-stress. Proteomics approach (one-dimensional (1D) and two-dimensional (2D) gel electrophoresis) compared differential protein abundance between controls and the osmotic stressed maize plants. Results: Morphological parameters such as plant growth, height, shoot diameter, leaf area, and colour were highly affected with PEG treatment as compared to the untreated ones. Molecular evaluation by 1D gel electrophoresis revealed that the separated protein patterns were highly expressed in the experiments than the controls. Using 2D gel electrophoresis, a total of seven and eight protein spots were revealed in experimental plants under 5% (w/v) and 10% (w/v) PEG treatment respectively while the control plants only expressed one protein. Increased drought stress resulted in a greater number of proteins with differential abundance. Conclusion: This study has successfully profiled the total osmotic stress responsive proteins and revealed the efficiency of proteomic tools in the qualitative detection of differential proteins from maize.

Differential methods of cell lysis for protein profiling of Alexandrium sp. using 2D gel electrophoresis

Introduction: Protein profiling of harmful algae is an ongoing study where the latest analysis was conducted on A. minutum. It is a fundamental study where the protein expression of targeted species can be used to understand the biochemical pathway of selected proteins. The Malaysia Alexandrium spp. has the potential to cause massive blooming that brings harm to the aquatic ecosystem. Methods: In this experiment three methods of cell lysis were tested against A. leei isolated from Malaysian waters. Results: The Axenic culture of the sample was established in enriched seawater media (ESDK) with 12 hours of light and 12 hours of dark conditions. The sample was extracted during exponential phase (day 18) where the same amount of cells was collected via centrifugation. The same buffer was used for each technique of cell lysis in order to get the best protein profiles in terms of a band or spot intensity and number. The cells of A. leei were lysed using sonication in the ice-cold water bath, sonication with probe and freeze-thawing followed by sonication in iced bath is the best method of protein extraction. Conclusions: Nevertheless, it can be concluded that the qualitative analysis using SDS-PAGE and 2D gel electrophoresis could be best method and the freeze thawing mode of cell lysis produced an excellent result among others as the protein spots produced were precise and less streaking were observed.