Shanghai scientists make new discovery in plant immunity

Shanghai scientists have discovered the correlation between two immune pathways that plants use to protect themselves against diverse pathogens, providing new insights into strategies of improving plant resistance to numerous diseases.

Plants have a two-layered immune system - comprising of pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) - to defend themselves against pathogens. Previous studies showed that PTI and ETI have significant differences in signaling initiation and early transduction events, and therefore have traditionally been considered to act independently.

A research group led by Xin Xiufang at the Center for Excellence in Molecular Plant Sciences affiliated with the Chinese Academy of Sciences – John Innes Center (UK) joint Center of Excellence in Plant and Microbial Science found that there exists an exquisite synergistic mechanism between PTI and ETI pathways and that PTI is an indispensable component of ETI.

A paper of their study was published on the website of the United Kingdom-based journal Nature on Thursday.

In the study, scientists found that PTI pathway activation is crucial for the production of ETI-associated reactive oxygen species (ROS). ETI-triggered ROS production is mainly mediated by a type of oxidase. The researchers also found that ETI can significantly upregulate the mRNA and protein level of the oxidase in a PTI independent manner, but the full activation of the oxidase during ETI depends on PTI signaling.

"Therefore, the PTI and ETI pathways work together to regulate the oxidase and production of ROS, and ETI strongly upregulates the transcript and protein levels of many key signaling components of PTI," said Xin.

"It's like ETI is a bomb producer and PTI is responsible for igniting them. They cooperate for counterfire when confronting attacks from pathogens," she said.

Xin said such findings may help researchers develop anti-pathogenic strategies for plants that make them more disease resistant.