Study Identifies Mechanism that Allows Plants to Tolerate Salt

Dec 14, 2018

By Brian Wallheimer

Purdue University scientists have discovered a signaling pathway necessary for plant salt tolerance. The findings are important for understanding how plants overcome some environmental stresses.

High salt already affects about 20 percent of the world’s arable land, reducing crop yields. By 2050, it’s thought that around half of all crop land will be impacted by salinity. Development of salt-tolerant crops, then, will be important for feeding a population expected to approach 10 billion by 2050.

Jian-Kang Zhu, distinguished professor of plant biology, Chunzhao Zhao, a senior researcher, and Omar Zayed, a doctoral student, identified a series of cell wall proteins that sense the salt-induced modification of cell wall. Those start a cascade, leading to the activation of intracellular signaling pathways that are essential to a plant’s growth in the presence of salt.

Purdue scientists, collaborating with colleagues at the Chinese Academy of Sciences and Nanjing Agricultural University, reported their findings in the Proceedings of the of the National Academy of Sciences.

Specifically, salt activates cell-wall leucine-rich repeat extensins (LRX) 3/4/5 in Arabidopsis, a model plant. Those proteins regulate the activity of two peptides – RAPID ALKALINIZATION FACTOR (RALF) peptides RALF22/23 – which interact with protein kinase FERONIA (FER) in the cell plasma membrane.

Plants with mutations of the LRX and FER genes, and plants with overexpressed RALF22 or RALF23 were sensitive to salt stress and did not grow well.

The research was funded by the Chinese Academy of Sciences.

Source:purdue.edu

Video: Why Your Food Future Could be Trapped in a Seed Morgue

In a world of PowerPoint overload, Rex Bernardo stands out. No bullet points. No charts. No jargon. Just stories and photographs. At this year’s National Association for Plant Breeding conference on the Big Island of Hawaii, he stood before a room of peers — all experts in the science of seeds — and did something radical: he showed them images. He told them stories. And he asked them to remember not what they saw, but how they felt.

Bernardo, recipient of the 2025 Lifetime Achievement Award, has spent his career searching for the genetic treasures tucked inside what plant breeders call exotic germplasm — ancient, often wild genetic lines that hold secrets to resilience, taste, and traits we've forgotten to value.

But Bernardo didn’t always think this way.

“I worked in private industry for nearly a decade,” he recalls. “I remember one breeder saying, ‘We’re making new hybrids, but they’re basically the same genetics.’ That stuck with me. Where is the new diversity going to come from?”

For Bernardo, part of the answer lies in the world’s gene banks — vast vaults of seed samples collected from every corner of the globe. Yet, he says, many of these vaults have quietly become “seed morgues.” “Something goes in, but it never comes out,” he explains. “We need to start treating these collections like living investments, not museums of dead potential.”

That potential — and the barriers to unlocking it — are deeply personal for Bernardo. He’s wrestled with international policies that prevent access to valuable lines (like North Korean corn) and with the slow, painstaking science of transferring useful traits from wild relatives into elite lines that farmers can actually grow. Sometimes it works. Sometimes it doesn’t. But he’s convinced that success starts not in the lab, but in the way we communicate.

“The fact sheet model isn’t cutting it anymore,” he says. “We hand out a paper about a new variety and think that’s enough. But stories? Plants you can see and touch? That’s what stays with people.”

Bernardo practices what he preaches. At the University of Minnesota, he helped launch a student-led breeding program that’s working to adapt leafy African vegetables for the Twin Cities’ African diaspora. The goal? Culturally relevant crops that mature in Minnesota’s shorter growing season — and can be regrown year after year.

“That’s real impact,” he says. “Helping people grow food that’s meaningful to them, not just what's commercially viable.”

He’s also brewed plant breeding into something more relatable — literally. Coffee and beer have become unexpected tools in his mission to make science accessible. His undergraduate course on coffee, for instance, connects the dots between genetics, geography, and culture. “Everyone drinks coffee,” he says. “It’s a conversation starter. It’s a gateway into plant science.”