Role of Phytohormones in Plant Defence Against Insects: Signalling and Crosstalk

Plants possess their own defence mechanisms to combat infestations of herbivorous insects and pathogens. It has few preexisting defence mechanisms, whereas most of the defence response is activated only after insect or pathogen invasion. Crosstalk between defence signalling pathways induced in response to herbivore/pathogen attack offer plants to regulate defence mechanism in an effective manner. Crosstalk and interaction of signalling pathways can function synergistically, or either one is suppressed under stress condition. Crosstalk enables the plant to utilize less energy for defence response and allocate energy for its growth and development. Host plant resistance against herbivores can be manipulated using chemical elicitors, which induces defence signalling mechanism in plants. Unravelling of defence mechanisms and phytohormonal signalling pathway under stress condition, the induced responses of the herbivores can be predicted, that can be further utilized for pest management and reduction in crop losses.