Complex interactions between insect-borne rice viruses and their vectors.

Insect-borne rice viral diseases are widespread and economically important in many rice-growing countries. Long-term associations between rice viruses and their insect vectors result in evolutionary trade-offs that maintain a balance between the fitness cost of the viral infection of insects and the persistent transmission of the virus by the insect. To promote optimal replication, rice viruses activate innate immune responses, such as autophagy, apoptosis, and stress-regulated signaling pathways in the vector; meanwhile, a conserved insect small interfering RNA antiviral pathway is activated to control excessive viral replication, guaranteeing persistent virus transmission. Furthermore, growing evidence has shown that rice viruses can manipulate their vectors either directly or by inducing changes in host plants to promote the spread of viral pathogens. Thus, understanding the plant-virus-insect relationships offers important insights into how disease epidemics occur and facilitates the design of powerful new strategies for disease control.