Plant scientist has life's work honored

Growing up in the agricultural heartland of Shandong province, as a boy Li Chuanyou would often ask his father about how plants grow.

Over four decades later, and Li is a globally recognized scientist specializing in plant molecular biology and genetics, specifically focusing on how plants defend themselves and grow.

In November, the dean of the College of Life Sciences at Shandong Agricultural University was honored with the Humboldt Research Award for his lifetime's work on plant hormone signaling.

After graduating from Shandong Agricultural University in 1994 with a master's degree in crop genetics and breeding, Li began his career there as a teacher and researcher.

It was his particular interest in how plants are able to signal that they are under attack and repair their damaged cells that took his interest.

"Plants cannot run or call for help when they get injured," Li said. "When an insect bites into a tomato leaf, how does the whole plant learn of the intrusion and quickly organize a defense?"

In the early 1970s, scientists in the United States discovered that plants send out an alarm when injured, believing a substance called systemin carried the message.

However, during his postdoctoral research at Michigan State University from 1999 to 2003, Li discovered that the long-distance mobile alarm signal was not systemin, but another hormone called jasmonic acid.

Systemin acted more like an "alarm amplifier", which turns up the volume at the injury site to ensure jasmonic acid can effectively activate the plant's full defense system, said Li.

His findings were hailed by the journal Science in 2002 as a major breakthrough in the field of signal transduction in plants and microbes.

Li pondered that if plants cannot escape harm, what do they rely on to repair damaged tissues?

Leading his team on a search that spanned over a decade, Li championed the idea that defense and regeneration in plant injury responses are inseparable.

Sifting through tens of thousands of mutant tomato variants and through genetic comparison, they pinpointed a key gene that can activate stem cells, allowing damaged tissues to regrow.

Last year, this achievement was published in the journal Cell, answering a long-standing scientific question of how plants achieve organ regeneration.

To advance tomato breeding, Li has collaborated with over 300 scientists from 14 countries to sequence the entire genome of cultivated tomatoes and their wild ancestor. "The genome contains all the genetic information controlling a plant's growth, ripening, flavor, firmness and more," Li said.

"This achievement has not only advanced functional genomics research in tomatoes and other Solanaceae crops like potatoes and eggplants, but also laid a solid foundation for breeding new, high-quality, disease-resistant varieties," he added.

In 2023, Shandong Agricultural University partnered with the city of Tai'an to establish the Taishan Academy of Tomato Innovation. Utilizing this platform, Li's team is working to standardize and brand tomato seed and seedling production, bridging fundamental research, molecular breeding and variety promotion.

Li and his breeding team have developed over 30 high-end tomato varieties, offering viable domestic alternatives to imported seeds.

"Our research must return to the land," Li told his students. "It must serve the farmers well and bring delicious food to the people."