Tentoxin

Tentoxin is a cyclic tetrapeptide produced by certain strains of the fungus Alternaria spp., particularly Alternaria alternata. It is known for its phytotoxic properties, specifically causing chlorosis in seedlings of certain plant species by inhibiting chlorophyll synthesis. Tentoxin targets the chloroplasts, leading to a failure in the establishment of the photosynthesis apparatus in susceptible plants.

The structure of tentoxin consists of a cyclic chain of four amino acids, making it a member of the cyclic tetrapeptide family. This structure is crucial for its mode of action, as it allows tentoxin to specifically bind to and inhibit the CF1 ATP synthase complex in chloroplasts. This inhibition disrupts the normal flow of protons across the chloroplast membrane, which is essential for the synthesis of ATP during photosynthesis.

Tentoxin's specificity towards certain plant species makes it an interesting subject for research in the field of plant pathology and weed control. However, its potential as a herbicide is limited due to its non-selective nature and the risk of affecting non-target plant species.