On March 5th, Molecular Plant published an online publication titled”A Tonoplast-associated Calcium Signaling Regulates Manganese Homeostasis in Arabidopsis” by Professor Wang Cun’s research team from Northwest A&F University Research papers. Zhang Zhenqian, a postdoctoral faculty member from the School of Life Sciences, Northwest A&F University, is the first author of the paper, and doctoral student Fu Dali and PhD student Sun Zhihui from the School of Biology, China Agricultural University are the co-first authors. Professor Wang Cun from the School of Life Sciences is the corresponding author.
Manganese is an essential trace element for plant growth and development, but acidic soil and waterlogged soil can cause toxic effects on plants. Soil pH is the most critical factor affecting the effectiveness of manganese, and the effectiveness of manganese gradually increases as the pH decreases. At present, 30%of the soil in the world is acid soil, and manganese toxicity has become one of the important factors limiting crop yield and quality. However, compared with other nutrient elements, the research of plant manganese is limited to the gene discovery and biological function verification of some manganese transporters, and its molecular regulation mechanism and key transport processes are still unclear. Therefore, it is of great significance to discuss in depth how plants absorb and utilize manganese from the external environment, as well as the molecular mechanism of transport and redistribution in the body, especially the adaptation mechanism of plants under high manganese stress and the effect of manganese nutrition efficiency under low manganese conditions. Research is of great significance to improving the yield and quality of crops.
Ca2+ is a widespread second messenger in eukaryotic cells and plays an important role in the process of plant response to adversity stress and growth and development. However, does Ca2+ signal participate in the regulation of manganese signal transduction pathway? If you participate, what is the specific molecular mechanism? This scientific question remains unresolved. Researchers used the Aequorin reporter gene and Fluo-4 staining method to determine for the first time that high manganese stress can induce Ca2+ signals. Based on this, the researchers further studied the role and molecular mechanism of calcium signal in high manganese stress. Through systematic screening, it was found that CPK4/5/6/11 in the CPKs family of calcium-dependent protein kinases physically interacted with the manganese transporter MTP8 located in the vacuolar membrane. Using a variety of protein interaction techniques proved the authenticity of the interaction between CPK4/5/6/11 and MTP8. Finally, through experiments such as in vivo and in vitro phosphorylation, yeast function complementation, element content determination, and physiological phenotype, it was found that CPK4/5/6/11 activates its transport activity by phosphorylating the 31st and 32nd serines of MTP8, thereby reducing the cytoplasm The excess manganese ions in the cell are transported into the vacuole to improve the ability of plants to withstand manganese poisoning. In addition, the simulated phosphorylation state of MTP8 can also improve the seed germination and seedling growth of plants under low manganese stress conditions.
This study for the first time clarified that high manganese stress can cause calcium signals in plant cells. This solved the long-standing doubts that have plagued scientists and systematically analyzed Ca2+-CPK4/5/The 6/11-MTP8 signaling pathway regulates the molecular mechanism of plant manganese homeostasis, which provides theoretical basis and technical support for the cultivation of beneficial heavy metal hyper-accumulation crops and toxic heavy metal low-accumulation varieties.
The research is supported by related national and school projects and topics.
Thesis link DOI:https://www.cell.com/molecular-plant/fulltext/S1674-2052（21)00078-2< /div>