Phytoalexins include

✅ Explanation: Phytoalexins are a diverse group of low molecular weight antimicrobial compounds produced by plants in response to biotic and abiotic stresses, including microbial infections. They act as a defense mechanism, inhibiting the growth and spread of pathogens. The options listed are all examples of phytoalexins:
-Pisatin: This is a phytoalexin produced by pea plants (Pisum sativum) in response to fungal infection
-Isocoumarin: Isocoumarins are a class of phytoalexins found in various plants, including carrots and potatoes.
-Phaseoline: This is a phytoalexin found in beans (Phaseolus vulgaris) that exhibits antifungal activity

🔑Key Points :
-Phytoalexins are secondary metabolites produced by plants in response to pathogen attacks.
-These compounds exhibit strong antimicrobial activity and accumulate at the site of infection to inhibit the growth of the invading pathogens.
-Phytoalexins play a crucial role in the plant's defense mechanism by providing a rapid and localized response to infection.
-Phytochelatins: These are small, cysteine-rich peptides that chelate heavy metals and are involved in the detoxification of metal ions in plants. They do not have antimicrobial properties and are not synthesized in response to pathogen infection.
-Phytochrome: Phytochromes are photoreceptor proteins in plants that regulate various aspects of growth and development in response to light conditions. They are not related to antimicrobial activity or pathogen response.
-Phytoalexins: These are antimicrobial substances synthesized by plants in response to pathogen attack. They accumulate at the site of infection and help in inhibiting the growth and spread of the pathogen. Examples include resveratrol in grapes and camalexin in Arabidopsis.
-Phytin: Also known as phytic acid, this compound is a storage form of phosphorus in plants, particularly in seeds. It is not involved in antimicrobial activity or pathogen response.