The Food and Agriculture Organization of the United Nations estimates that between 20 and 40 percent of global crop production is lost each year due to plant pests and infections with microbial pathogens.
According to the article, scientists found their first clue in tomatoes, which contain a class of proteins that behave differently from those in the immune systems of other plants.
Most plants have two lines of defense: one on the surface of the cells and one within them, dominated by a disease-resistant protein called NLR.
These proteins, encoded by disease resistance genes, recognize specific invading pathogens and overwhelm the immune system, creating an efficient and rapid response and helping the plant deal with its enemies.
Typically, the proteins are tightly regulated and present at relatively low levels. But in the heat of the moment, when the immune response is activated, it can trigger a ‘suicide’ mechanism that leads to cell death and inhibits plant growth.
However, the researchers found that tomatoes had a class of proteins from the same family that did not appear to follow this pattern.
According to Chai and his colleagues, levels of this protein – called NRC – remain high regardless of whether the plant is attacked, potentially causing an overreaction of the immune system and even cell suicide.
The researchers analyzed the structure of the tomato proteins and found that they remain stable by assembling into different shapes with the help of a small organic molecule involved in the process of the plant’s energy metabolism.
Cao Yu, a researcher who works in the same laboratory as Chai, said the identification of the mechanism, including the helper, “has important implications” by providing a new theoretical basis for crop breeding and pest control.
The research could open up new agricultural biotechnologies to improve disease resistance in crops without disrupting their normal growth and yield by causing an excessive immune response, he said.
Scientists have long known that plants, like animals, are equipped with an immune system, with the cloning of the first gene for resistance to plant diseases in 1994 providing molecular evidence. But the biochemical functions of plant NLR proteins remained poorly understood.
Shi, a young assistant professor in Princeton University’s molecular biology department, accepted Chai as his first postdoctoral fellow in 1999.
Last year, in an interview with The Economic Observer in China, Shi described his former student as “one of the world’s leading scientists” in his field.
Upon returning to China in 2004, Chai joined the National Institute of Biological Sciences in Beijing as an independent principal investigator, focusing his research on the then fledgling field of plant immunology.
Last August, Chai and his long-time collaborator Zhou Jianmin won the prestigious Chinese Future Science Prize for their groundbreaking contributions to the understanding of immune mechanisms in plants.
Zhou, a researcher at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, and Chai shared in the $1 million prize, which was initiated in 2016 by a group of scientists and entrepreneurs to promote basic scientific research in China.
The privately funded award recognizes outstanding scientists in three main areas: life sciences, physical sciences, and mathematics and computer science.