Unlike animal viruses, the transmission of plant viruses depends more on insect vectors due to the lack of host mobility. Among 1,400 plant viruses worldwide, nearly 80% are transmitted by insect vectors. Currently, controlling viral plant diseases relies almost completely on chemical pesticides, creating enormous ecological and environmental costs.

Prof. YE’s team has focused on the geminivirus and bunyavirus – two types of arbovirus that cause many notorious crops diseases in developing countries. "Previous studies on arbovirus diseases often focused on the interactions of viruses and plant hosts, or viruses and host insects, thus failing to generate effective measures for controlling viral diseases. Our findings identify better control methods for arbovirus diseases,” said Prof. YE.

The researchers in this study found that plants have evolved a dual fail-safe switch to counter whitefly-transmission of geminivirus. That safe switch could integrate external environment and internal signaling to defense. Geminivirus infection turn-off this switch to dramatically reduce the light-controlled plant metabolites terpenes, which function as repellent for whitefly.

They identified a helix-rich domain of geminiviral protein βC1 serves as an inhibitor of PHYTOCHROME-INTERACTING FACTORS (PIFs) transcription factors which are also positive promoters of biosynthesis of terpene repellent for whitefly.

"Red light secures plant host immunity against begomovirus, the largest genus of plant viruses and transmitted exclusively by whitefly. However, it always run the red light by counterdenfensing host immunity,” said Prof. YE. "We could apply Far-Red Radiation LED lights technology which inactive the viral protein βC1.”

This study presents a novel scenario of how a pathogen adapts environmental conditions for vector attraction and pathogen spread. It will help to address similar tripartite interaction systems in plants, animals and humans and allow innovative control methods through interference with vector transmission.