Systemin is a plant peptide hormone that plays a crucial role in the plant's defense mechanism, particularly within the plant vascular system. As a Systemin supplier, I have delved deep into understanding how this remarkable peptide functions, and I'm excited to share these insights with you.
The Discovery and Basics of Systemin
Systemin was first discovered in tomato plants in the early 1990s. It is an 18 - amino - acid peptide that is cleaved from a larger precursor protein, prosystemin. This discovery was a significant milestone in plant biology as it was one of the first identified peptide hormones in plants. Unlike animals, plants do not have a circulatory system with a heart to pump fluids. Instead, they rely on the vascular system, which consists of the xylem and phloem, to transport water, nutrients, and signaling molecules.
Systemin's Role in Plant Defense
When a plant is attacked by herbivores or pathogens, systemin is released. This release is a crucial step in triggering the plant's defense response. The damaged cells at the site of the attack produce systemin, which then enters the phloem. The phloem is responsible for transporting sugars and other organic molecules throughout the plant, and it serves as the highway for systemin to travel from the site of damage to other parts of the plant.
Once systemin is in the phloem, it is carried to distant tissues. When it reaches its target cells, systemin binds to a specific receptor on the cell membrane. This receptor is a transmembrane protein that has a high affinity for systemin. The binding of systemin to its receptor activates a signal transduction pathway within the cell.
The signal transduction pathway involves a series of biochemical reactions. One of the key components in this pathway is the activation of mitogen - activated protein kinases (MAPKs). These kinases phosphorylate other proteins, leading to the activation of genes involved in the production of defense - related compounds. For example, genes encoding protease inhibitors are activated. Protease inhibitors are proteins that can inhibit the activity of digestive enzymes in herbivores, making the plant less palatable and more difficult to digest.
The Movement of Systemin in the Vascular System
The movement of systemin in the phloem is driven by the pressure - flow mechanism. The phloem sap, which contains sugars and other solutes, moves from areas of high pressure (source regions, where sugars are produced) to areas of low pressure (sink regions, where sugars are used or stored). Systemin, being dissolved in the phloem sap, is carried along with the flow.
The rate of systemin movement can vary depending on several factors. The distance between the site of damage and the target tissues is an important factor. Longer distances may result in a longer time for systemin to reach its destination. Additionally, the physiological state of the plant can also affect systemin movement. For example, a plant under stress may have a reduced phloem flow rate, which can slow down the movement of systemin.
Comparison with Other Peptide Hormones
In the world of peptide hormones, there are other well - known examples such as Secretin, Porcine, Eledoisin, and VIP (human, Bovine, Porcine, Rat). Secretin is a peptide hormone in animals that regulates pancreatic secretions. Eledoisin is a peptide found in the salivary glands of certain marine animals and has various physiological effects. VIP is a vasoactive intestinal peptide that plays roles in the regulation of blood flow and neurotransmission in animals.
While these peptide hormones have different functions in animals, they share some similarities with systemin in terms of their mode of action. All of them bind to specific receptors on the cell surface and activate signal transduction pathways. However, the specific receptors, signaling molecules, and downstream effects are different due to the different physiological contexts in which they operate.
The Importance of Systemin in Agriculture
The study of systemin has significant implications for agriculture. By understanding how systemin works in the plant vascular system, we can develop strategies to enhance plant defense against pests and diseases. For example, genetic engineering techniques can be used to overexpress systemin or its receptor in plants. This can lead to a more robust and rapid defense response, reducing the need for chemical pesticides.
Moreover, as a Systemin supplier, we can provide high - quality systemin to researchers and agricultural companies. Our systemin products are carefully purified and tested to ensure their biological activity. Researchers can use our systemin to study the molecular mechanisms of plant defense, while agricultural companies can explore its potential applications in crop protection.
Contact for Purchase and Collaboration
If you are interested in purchasing Systemin for your research or agricultural projects, we invite you to contact us for a detailed discussion. Our team of experts is ready to assist you in choosing the right product and providing technical support. Whether you are a scientist looking to unravel the mysteries of plant biology or an agricultural entrepreneur seeking innovative solutions for crop protection, we are here to help.
References
- Pearce, G., Strydom, D. J., Johnson, R., & Ryan, C. A. (1991). A polypeptide from tomato leaves induces wound - inducible proteinase inhibitor genes. Science, 253(5024), 895 - 898.
- Ryan, C. A., & Pearce, G. (1998). Systemin: a polypeptide signal for plant defense responses. Annual Review of Plant Physiology and Plant Molecular Biology, 49, 87 - 105.
- Schilmiller, A. L., & Howe, G. A. (2005). Jasmonate signaling: a conserved response to attack. Current Opinion in Plant Biology, 8(4), 369 - 377.