How do plants cope with their attackers? Can plants defend themselves?
YES, plants have sophisticated defence mechanisms against herbivorous insects and pathogens that constantly attack them. When attacked by herbivorous insects, plants exhibit dynamic biochemical changes resulting ultimately in direct and/or indirect defence responses. Direct plant defences range from hard waxy plant surfaces, thorns, toxic chemicals (eg. alkaloids, tannins, flavanoids) to defensive proteins like protease inhibitors or polyphenol oxidases. Indirect plant defences are those which help in recruiting carnivorous predators (third trophic level). By emitting volatile organic compounds (VOCs) plants signal predatory wasps or parasitoids to oviposit on the larvae feeding them. Further, some plants also secrete sugary, sweet extrafloral nectar (EFN) on leaves,stem or petiole to attract (and sometime house) ants that act as very effective bodyguards against feeding insect larvae. Overall, plants are quite smart and are capable of defending themselves, otherwise our world would no longer be green!
Can plants regulate their defences? Plants regulate their defensive response using phytohormones, small molecules that are very important for plant growth, development and defence. We study hormones like jasmonates (JA), cytokinins (CKs) and salicylic acid (SA) to understand their role in defence regulation. Initially, phytohormones were thought to individually influence a specific aspect of plant metabolism. However, recent evidences have shown that phytohormones interact with each other and form a web of overlap signaling.
How do plants sense herbivore attack ? Herbivore recognition by plants is crucial to activate appropriate defence responses rapidly and accurately. Usually simple mechanical wounding (such as puncture wounds or cuts) do not elicit VOC, EFN or any defence gene up-regulation. However when a larval oral secretion (OS) is applied to these wounds, we see an immediate burst of responses. This clearly shows that plants can sense what is eating them and this recognition comes from elements in the OS. In our lab,we are attempting to screen for plant defence elicitors from insect OS. We use phytohormone profiling as well as defence up-regulation as indicators of elicitor activity.
YES, plants have sophisticated defence mechanisms against herbivorous insects and pathogens that constantly attack them. When attacked by herbivorous insects, plants exhibit dynamic biochemical changes resulting ultimately in direct and/or indirect defence responses. Direct plant defences range from hard waxy plant surfaces, thorns, toxic chemicals (eg. alkaloids, tannins, flavanoids) to defensive proteins like protease inhibitors or polyphenol oxidases. Indirect plant defences are those which help in recruiting carnivorous predators (third trophic level). By emitting volatile organic compounds (VOCs) plants signal predatory wasps or parasitoids to oviposit on the larvae feeding them. Further, some plants also secrete sugary, sweet extrafloral nectar (EFN) on leaves,stem or petiole to attract (and sometime house) ants that act as very effective bodyguards against feeding insect larvae. Overall, plants are quite smart and are capable of defending themselves, otherwise our world would no longer be green!
Can plants regulate their defences? Plants regulate their defensive response using phytohormones, small molecules that are very important for plant growth, development and defence. We study hormones like jasmonates (JA), cytokinins (CKs) and salicylic acid (SA) to understand their role in defence regulation. Initially, phytohormones were thought to individually influence a specific aspect of plant metabolism. However, recent evidences have shown that phytohormones interact with each other and form a web of overlap signaling.
How do plants sense herbivore attack ? Herbivore recognition by plants is crucial to activate appropriate defence responses rapidly and accurately. Usually simple mechanical wounding (such as puncture wounds or cuts) do not elicit VOC, EFN or any defence gene up-regulation. However when a larval oral secretion (OS) is applied to these wounds, we see an immediate burst of responses. This clearly shows that plants can sense what is eating them and this recognition comes from elements in the OS. In our lab,we are attempting to screen for plant defence elicitors from insect OS. We use phytohormone profiling as well as defence up-regulation as indicators of elicitor activity.