Endophytes Are Magic Helpers For Making Natural Products

Much like the elves from “Grimm’s Fairy Tales” who secretly turn up at night to make shoes for a poor cobbler in need, chemists have discovered a plant-dwelling microbial community that is a hidden producer of a natural product with potent anticancer properties (J. Nat. Prod. 2014, DOI: 10.1021/np500219a). The discovery lends growing evidence that some metabolites found in plants are actually produced by associated bacteria or fungi, rather than the plants themselves. A team led by Souvik Kusari and Michael Spiteller of the Technical University of Dortmund, in Germany, explored the root endophytic communities of shrubby Putterlickia plants of South African origin and evaluated their fermentation products using a microbiological assay and high-pressure liquid chromatography/high-resolution mass spectrometry. The researchers discovered that the microbes produce maytansine, one of the most potent cellular microtubule-targeting compounds used for treating breast cancer. They further confirmed the results via genetic studies and mass spec imaging to show that maytansine produced by the endophytes accumulates mainly in the roots of the plants. The team is now studying whether maytansine is produced by a single organism or by cross talk between two or more members of the endophyte community in order to possibly produce the drug biosynthetically.