With average sea surface temperatures increasing around the world, coral bleaching events are growing in extent and severity. More than two thirds of the corals in the Great Barrier Reef, the world’s largest coral reef, have already bleached. While the physiological consequences of coral bleaching are well-studied, we still don’t fully understand how bleaching happens on a cellular level.
Steve Palumbi at Stanford University is delving deeper into the mechanisms by which coral bleaching occurs. In 2018, Promega pledged $3 million over three years to the nonprofit Revive & Restore Catalyst Science Fund, to identify and develop advanced techniques for conservation, enhancing biodiversity, and genetic rescue. Palumbi was awarded the first grant from this fund to study the genomic stress trigger that causes corals to bleach in warming oceans.
A paper published in Science this week describes use of engineered tobacco plants to produce a precursor of etoposide, a key anti-cancer drug. The paper illustrates how engineered crops could be used for production of drugs or other compounds that are difficult to isolate or purify from natural sources.
Although etoposide is derived from a plant compound, little is known about its natural biosynthetic pathway. The authors of the paper first used genome mining to identify candidate genes that may be involved in synthesis of the etoposide precursor in its native host—the rare and slow-growing mayapple plant. Through a complex process of elimination, were eventually able to identify 10 enzymes involved in biosynthesis, and reconstitute the pathway in engineered tobacco plants.
The paper showcases some elegant scientific detective work, making use of both genomic analysis and classical genetic engineering to solve the puzzle of etoposide biosynthesis. The results presented also illustrate the potential benefit of engineering agricultural crops to be used as drug production systems, and generate hope for a much more abundant, easily cultivable supply of these and other therapeutic compounds.
The use of tobacco to generate an anti-cancer compound. Delightful science.