Reactive Oxygen Species and Antioxidant Defence Systems in Plants: Role and Crosstalk Under Biotic Stress

Abstract

The plant defence system always acts under the influence of many biotic and abiotic factors, and it has a prime key role in enhancing crop yield potentiality by improving quality as well as disease resistance. Similar to abiotic stress, biotic stress plays a critical role in accelerating reactive oxygen species (ROS) production in the plant system. ROS are generated in response to stress-responsive stimuli and generally regarded as oxidative stress indicative marker. ROS were initially recognized as toxic by-products of stress metabolism causing oxidative stress damage. However, the importance of ROS as signal transduction molecules in the regulation of various biological processes involved in growth, development and different pathways during plant adaptation to various biotic stresses has also been deciphered. To restrict pathogen invasion, a delicate spatio-temporal balance between ROS-producing and ROS-scavenging pathways is essential for the utilization of ROS as signalling molecules and highly crucial for sustainable agriculture. Besides this, plants also developed another survival mechanism that deals with antioxidant systems having two different components, namely, enzymatic and non-enzymatic. These two antioxidant systems coordinately work together, and the generated functional proteins are overexpressed during pathogen attack to ensure the molecular defence response in resistant and/or tolerant plant species. The role of ROS in correlation to antioxidant systems in plant cells is gaining attention due to the fact that ROS are having valuable contribution towards increasing the response in plant defence systems at the molecular level. In the present chapter, we have described some newer aspects of ROS signalling networks in plants under biotic stress along with the use of synthetic biology approaches in increasing a better defence system, especially in crop plants. The molecular network between ROS signalling and antioxidant systems during defence response is also addressed. Further, the chapter also describes the novel techniques being investigated in order to understand the mechanism of signalling networks and metabolic networks in plant systems under biotic stress condition.