Global chocolate supply threatened by disease, new cacao plant offers solution

UNIVERSITY PARK, Pa. — Chocolate lovers may not realize it, but the future of one of the world's most popular foods is increasingly under pressure. Diseases, shifting weather patterns and other environmental stressors are threatening cacao production globally, contributing to supply concerns and economic challenges for the millions of farmers who grow the crop that makes chocolate possible.

Now, after decades of research, Penn State scientists have developed a new disease-tolerant variety of cacao — and they said it has the potential to fundamentally change the chocolate industry.

The new cacao variety builds on decades of research led by Mark Guiltinan, J. Franklin Styer Professor of Horticultural Botany and professor of plant molecular biology in the Department of Plant Sciences at Penn State's College of Agricultural Sciences, and Siela Maximova, research professor of plant biotechnology in the same department.

“For consumers, chocolate is something they expect to find on store shelves every day, but behind that product is a crop and industry facing significant challenges,” Guiltinan said. “Our goal is to develop tools that help growers continue producing cacao sustainably and profitably.”

Penn State's Program in the Molecular Biology of Cocoa, which Guiltinan and Maximova co-direct, traces its roots to an industry-supported endowment established in the 1980s. Since then, researchers at the University have developed foundational tools for cacao biotechnology, mapped important genetic pathways, and built one of the world's leading cacao research programs.

The University recently entered into a licensing agreement with AgroNetica, a cacao-focused biotechnology company, to work toward bringing the plant to growers worldwide. The company will advance field testing of the plants with the goal of eventually marketing the plant directly to growers, helping address some of the most significant threats facing global chocolate production.

The AgroNetica agreement represents a new chapter in the University’s effort to understand and improve cacao, Maximova said, one focused on translating discoveries into technologies that can help growers, strengthen supply chains and support the future of chocolate production.

“Thanks to this long-term investment in research and maintaining a sustained program, we now have an opportunity to begin getting technologies developed here in the lab closer to the hands of farmers,” Maximova said. “The focus was always on helping cacao farmers and the industry. We're now at the place where we have a partner whose expertise is moving these discoveries into real-world use.”

According to Guiltinan, this new commercialization opportunity is particularly important as cacao production worldwide faces mounting threats from disease, climate variability, and changing environmental conditions that jeopardize both grower livelihoods and supply chains.

Black pod disease, an especially destructive disease caused by a mold-like pathogen, alone is estimated to cause yield losses of roughly 30% worldwide, he said, while climate-related stresses continue to threaten production in major cacao-growing regions.

Native to the Amazon rainforest, cacao evolved as an understory tree growing beneath a tropical forest canopy. Today, it is cultivated across tropical regions in Africa, Asia and Latin America, often under environmental conditions that are very different from those in which the species evolved.

“Cacao evolved in a very stable rainforest environment,” Guiltinan said. “It's a delicate plant in many ways. Changes in rainfall, temperature and humidity can all affect production, and some of those changes can also increase disease pressure.”

Traditional cacao breeding is notoriously slow. Maximova explained that developing and evaluating new varieties can take decades because cacao trees require roughly three years to mature and produce seed. That slow rate of growth means climate change is an especially dangerous threat to its survival, she added. Not only are environmental conditions shifting faster than plants can evolve, but increased humidity and weather variability can create favorable conditions for pathogens and insect pests.

“The climate is changing faster than these trees can naturally adapt,” she said. “One of our goals is to develop tools that help breeders respond more quickly to those challenges.”

In a study published in the Plant Biotechnology Journal, the researchers combined advanced genetic tools such as genome sequencing and editing with traditional plant breeding to create a cacao plant with significantly improved resistance to black pod disease.

Using gene editing technology (CRISPR), the scientists modified a cacao gene known as TcNPR3, which acts as a natural brake on the plant's immune system. The mutation partially activates the plant's defense response, increasing its defenses against subsequent pathogen infection. After introducing the desired edit, researchers bred the plants to remove all transgenic material, or foreign DNA associated with the gene-editing machinery, leaving only the beneficial genetic change.

The result was a cacao plant carrying a precise genetic modification for disease tolerance, but no longer considered a genetically modified organism or GMO, consistent with U.S. and European Union regulatory frameworks that treat certain gene-edited traits similarly to those developed through conventional breeding.

“In one case, we only changed two bases in the entire genome of the plant,” Guiltinan said. “Out of roughly 450 million bases, that single change resulted in about a 42% reduction in disease under laboratory conditions.”

Although the edited plants have shown promising results in laboratory testing, the researchers emphasized that further work is needed before growers could plant them commercially. Field evaluations are underway through collaborations with the U.S. Department of Agriculture in Hawaii and Puerto Rico, where researchers will assess performance under real growing conditions.

“These plants are specifically designed to improve disease resistance,” Maximova said. “The next step is proving performance in field trials. Scale-up and marketing will be the next challenges should the field testing prove encouraging. That's where commercial partners can play an important role in helping move the technology forward.”

She noted that commercialization of improved cacao varieties requires substantial investment, beyond what universities are designed to provide.

That’s where AgroNetica comes in. The company recently licensed the commercial rights to the plants carrying the mutation for disease tolerance. AgroNetica has a plan to test, scale up and sell new varieties of cacao with improved traits for more sustainable production in cacao-growing countries. The company also plans to introduce additional traits from its development pipeline aimed at improving heat and drought resilience, reducing cadmium accumulation, enabling more compact plant architecture and greater mechanization, accelerating time to first harvest, and developing caffeine-free cacao varieties.

“It takes millions of dollars and many years to bring a new crop variety to farmers,” Maximova said. “That's why partnerships with companies willing to invest in development, testing and deployment are so important.”

While the licensed technology focuses on resistance to disease, Maximova and Guiltinan are also studying traits related to climate resilience and crop productivity. Accelerated breeding and genome editing will become increasingly important tools as environmental pressures on cacao production continue to grow, they explained.

“The diseases are changing. The climate is changing. The challenges growers face continue to evolve,” Maximova said. “This is not something you solve once and then you're finished. It's an ongoing effort to develop better plants and provide growers with new options.”

For Guiltinan, the licensing agreement represents more than a commercial milestone. It is evidence that long-term university research can lead to tangible benefits for agriculture.

“We're trying to solve real problems for farmers,” he said. “If we can help growers reduce losses, improve productivity and adapt more quickly to changing conditions, then that's the ultimate measure of success.”