We already know that's the case for antibiotics. And we know plants compete with one another by suppressing competitors' growth.
Seems to me Thomas's comment is intended to add a loophole -- "we created this cDNA and patented it, so we have the patent, so if you claim you found the exact same thing out there in nature somewhere, it must be you stole it from us." Betcha.
The Future of Antibiotics and Resistance
Brad Spellberg, M.D., John G. Bartlett, M.D., and David N. Gilbert, M.D.
N Engl J Med 2013; 368:299-302January 24, 2013DOI: 10.1056/NEJMp1215093
"... after billions of years of evolution, microbes have most likely invented antibiotics against every biochemical target that can be attacked — and, of necessity, developed resistance mechanisms to protect all those biochemical targets. Indeed, widespread antibiotic resistance was recently discovered among bacteria found in underground caves that had been geologically isolated from the surface of the planet for 4 million years.2 Remarkably, resistance was found even to synthetic antibiotics that did not exist on earth until the 20th century. These results underscore a critical reality: antibiotic resistance already exists, widely disseminated in nature, to drugs we have not yet invented.
"Thus, from the microbial perspective, all antibiotic targets are “old” targets...."