response to fungus

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus from a fungus. [GOC:hb]

Response to fungus is a complex and highly orchestrated process involving a wide range of cellular and molecular mechanisms. It is essential for plants and animals to defend themselves against fungal pathogens, which can cause diseases, damage crops, and even be fatal. Here's a detailed description of the key biological processes involved:

1. **Recognition of the Fungal Pathogen:** The first step in responding to fungus is recognizing its presence. This is typically achieved through the detection of specific fungal molecules called pathogen-associated molecular patterns (PAMPs). PAMPs are conserved structures found on the surface of fungal cells, such as chitin, glucans, and fungal proteins.
2. **Activation of Immune Signaling Pathways:** Once a PAMP is detected, it triggers a cascade of signaling events within the host organism. This can involve activation of receptor kinases on the cell surface, which in turn activate intracellular signaling pathways. Key pathways involved in plant defense against fungi include the MAPK (mitogen-activated protein kinase) cascade and the jasmonic acid (JA) signaling pathway. In animals, Toll-like receptors (TLRs) play a crucial role in recognizing fungal PAMPs and initiating immune responses.
3. **Production of Defense Molecules:** The activation of signaling pathways leads to the production of various defense molecules, including antimicrobial peptides, enzymes, and reactive oxygen species (ROS). Antimicrobial peptides can directly kill fungal cells by disrupting their cell membranes, while enzymes like chitinases and glucanases degrade fungal cell walls. ROS can act as signaling molecules and also have direct antimicrobial activity.
4. **Cell Wall Strengthening:** In plants, the cell wall plays a critical role in defending against fungal pathogens. In response to fungal infection, plants reinforce their cell walls by depositing callose, a polysaccharide that acts as a barrier against fungal penetration.
5. **Hypersensitive Response (HR):** In some cases, plants mount a hypersensitive response (HR) to fungal infection. This is a localized programmed cell death that restricts the spread of the fungus. The HR involves the rapid production of ROS and the accumulation of defense-related molecules.
6. **Immune Memory:** Some organisms, particularly plants, exhibit immune memory, where exposure to one pathogen can prime them for faster and stronger responses to subsequent infections, including those by different fungal species.

These processes are interconnected and work in concert to provide robust protection against fungal infections. The specific mechanisms and responses can vary depending on the host organism, the fungal pathogen, and environmental conditions.'
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Proteins (2)

Compounds (9)