Developing an Association Network from Proteome Changes to Root Phenotypic Properties for Aluminum Tolerance in Switchgrass
Aluminum (Al) is a major limiting factor for plant growth and development on acidic soil when the pH level decreases below 5.0. The presence of excess Al3+ concentration induces an inhibitory effect on cell division and elongation of root tips leading to the development of a small root system. This study was performed to reveal the cell type specific molecular mechanisms of Al responses thus providing the fundamental knowledge for Al tolerance and sensitivity in plants. Switchgrass was selected due to its tolerance to Al and other environmental conditions including soil acidity. Two independent experiments were conducted. In the first experiment, Al-induced proteomic changes in different switchgrass root zones were identified. The second experiment focused on the identification of protein expression changes in switchgrass root epidermal cells under aluminum stress. Al-induced changes in proteomes were identified using tandem mass tags mass spectrometry (TMT-MS)-based quantitative proteomics analysis. A total of 554 proteins showed significant differences between non-Al treated control and treated groups with significant fold changes (twice the standard deviation; FDR adjusted p-value < 0.05). These SCPs from the roots were classified using bioinformatic tools such as MapMan, STRING, and PANTHER software. In this study, proteins related to cell wall modifications (xyloglucan endotransglucosylase-hydrolase), cell cycle (rotamase FKBP 1 isoforms, and CDC48 protein), and cell shape/structure maintenance (actin and microtubule) were identified. The phosphate (Pi) transporter was greatly induced, but the potassium (K) transporter was repressed. A large number of Al-responsive proteins, including transcription factors, ASR5, an important Al-tolerance TF (Transcription factors), and several proteins related to root hair initiation and development were induced. This study has provided novel information on the role of root apex and epidermal proteome expression under Al stress. The identification of Al-induced SCPs in the root tip, root elongation and epidermal cells will help in developing a more targeted approach for developing Al-resistant/tolerant plants.
"Developing an Association Network from Proteome Changes to Root Phenotypic Properties for Aluminum Tolerance in Switchgrass"
ETD Collection for Tennessee State University.