MEWS OF THE MEEK NATURAL
PRODUCTS
SYMBIOSIS IS BEHIND RICE BLIGHT Fungal toxin blamed for disease turns out to be made by symbiotic bacterium
R PARTNERS IN BLIGHT Rhizoxin is produced not by the fungus itself but by bacteria (green) living inside.
MERGERS
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ICE SEEDLING BLIGHT, AN
economically costly agricultural disease, is caused by a toxin released by certain Rhizopus fungi. Long thought to be produced by the fungus itself, this toxin has now been shown to be biosynthesized by bacteria that live symbiotically inside the fungus. This unexpected finding— by professor Christian Hertweck and graduate student Laila P. PartidaMartinez of the Leibniz Institute for N a t u r a l Products Research & Infection Biology in Jena, Germany—reveals a complex and unprecedented symbiotic alliance that pits fungus and bacterium against plant
{Nature 2 0 0 5 , 437, 884). At the center of this alliance is rhizoxin, a macrocyclic polyketide natural product produced by the bacterium. Rhizoxin binding to a rice structural protein known as (3-tubulin blocks cell division and weakens or kills the rice plant. By showing t h a t an antibiotic can be used to generate a symbiont-free fungus unable to produce rhizoxin, Hertweck and Partida-Martinez have revealed new strategies for controlling rice seedling blight. "It could be possible to control the disease by applying antibiotics rather than antifungal agents," Hertweck says. Rhizoxin is a potent anticancer
ACQUISITIONS
Reilly Industries Is Acquired By Investment Firm
T
he owners of Reilly Industries, one of the U.S. chemical industry's last family-held companies, have sold a majority interest in their firm to the investment group Arsenal Capital Partners for $250 million. Indianapolis-based Reilly makes pyridine and derivatives, coal tar products, the insect repellant A/,/V-diethyl-m-toluamide (DEET), and other specialty chemicals. It has annual sales of about $300 million from seven plants in the U.S., Europe, and Asia. According to Reilly CEO Robert D. McNeeley, the sale fits with his firm's plan to expand existing businesses and enter new ones. He notes that the sale also provides Reilly family members with the liquidity to diversify their holdings. The family will continue to maintain a minority interest in the company. McNeeley, a long-time Reilly executive, became the company's first nonfamily CEO
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when he replaced Thomas E. Reilly Jr. in 2001. Arsenal Managing Director Barry Siadat says his firm invests in niche market leaders in the specialty chemical industry and thus has long been interested in Reilly for its strong positions in DEET; vitamin B-3; citrate esters; and pyridine, a feedstock for the herbicide paraquat. Arsenal, which was formed in 2001, already owns Scientific Protein Laboratories and Rutherford Chemicals, the former specialty chemical business of Cambrex. Siadat sees synergies among these holdings, particularly in the personal care, pharmaceutical, agrochemical, and polymer additive markets. Siadat says Arsenal is committed to funding recently announced Reilly plant expansions in Indianapolis and China. He also anticipates other chemical industry deals for the investment group.-MICHAEL MCCOY
agent, but toxicity problems have prevented its use as a drug. Thanks to their success in cultivating the bacterium outside its fungal host, the researchers have been able to isolate rhizoxin, as well as novel rhizoxin analogs, Hertweck tells C&EN. His lab hopes that metabolic engineering may lead to other rhizoxin derivatives with improved properties. "The exciting aspects of this research go beyond the prospects for controlling seedling blight in rice
0CH3 Rhizoxin
and using rhizoxin to treat cancer," writes ecologist Ian R. Sanders of Switzerland's University of Lausanne in an accompanying Nature commentary. "The existence and evolution of such a symbiosis between the fungus and bacterium are in themselves intriguing." W h a t the partners get out of the alliance remains unclear. The fungus certainly profits from the nutrients provided by the decaying rice plant. But why doesn't the bacterium strike on its own? And how do both bacterium and fungus resist the toxic effects of rhizoxin? Hertweck's lab hopes that further study of this unusual alliance will provide answers to these questions. Symbiotic natural product producers have recently been fingered in creatures as diverse as beetles, sponges, and microscopic marine animals. "The discovery of more and more examples of chemically mediated symbiotic complexity bodes well for drug discovery," comments medicinal chemist Eric W. Schmidt of the University of Utah. "These relationships may reveal new sources of novel natural products.'-AMANDAYARNELL
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