Texas A&M AgriLife Scientists Find New Defense Against Hard-To-Treat Plant Diseases

Scientists at Texas A&M AgriLife Research have developed a new approach to countering citrus greening and potato zebra chip diseases, two economically devastating agricultural diseases in the U.S. The scientists used spinach antimicrobial peptides, known as defensins, which naturally defend plants against a broad range of pathogens.

The research team, led by Kranthi Mandadi, Ph.D., an AgriLife Research plant molecular biologist and professor in the Texas A&M Department of Plant Pathology and Microbiology, showed that some spinach defensins confer similar protection to citrus and potatoes, and possibly to other crops. The effects show significant progress toward recovering yield and improving quality in diseased plants.

Mandadi and his team successfully used naturally occurring antimicrobial peptides from spinach to combat citrus greening disease in commercial citrus trees. These safe peptides, delivered via a benign virus that naturally infects the trees where the bacteria reside, led to promising results, including up to 50% increases in fruit yield after a single application compared to untreated trees.

The team also found that the peptides can effectively combat plant diseases, including potato zebra chip disease, caused by a bacterium related to citrus greening. When expressed in potatoes, these safe, naturally occurring peptides reduced disease symptoms, lowered bacterial presence, minimized discoloration in tubers, and increased tuber yield. This success, alongside their effectiveness in citrus, encourages broader applications, with plans to create "peptide cocktails" and integrate them with insect control strategies to further manage bacterial spread.

For more details, read the news release in Texas A&M Stories.