Oranges, olives, and bananas are already under threat in many areas due to diseases that affect plants’ circulatory systems and that cannot be treated by applying pesticides. A new method developed by engineers at MIT may offer a starting point for delivering life-saving treatments to plants ravaged by such diseases. The method uses an array of microneedles made of a silk-based biomaterial to deliver nutrients, drugs, or other molecules to specific parts of the plant. The work started in response to a request from the U.S. Department of Agriculture for ideas on how to address the citrus greening crisis, which is threatening the collapse of a $9 billion industry.
The microneedles designed for human use were intended to biodegrade naturally in the body’s moisture, but plants have far less available water, so the material didn’t dissolve and was not useful for delivering the pesticide or other macromolecules into the phloem. The researchers had to design a new material, but they decided to stick with silk as its basis. That’s because of silk’s strength, its inertness in plants (preventing undesirable side effects), and the fact that it degrades into tiny particles that don’t risk clogging the plant’s internal vasculature systems.
The technology has potential to be used to bioengineer disease-resistant varieties of important crops. In experiments with tobacco the researchers were able to inject Agrobacterium to alter the plant’s deoxyribonucleic acid – a typical bioengineering tool, but delivered in a new and precise way.
Read more at MIT News