A recent study in plastid genetic engineering from the PDS' laboratories has greatly advanced chloroplast metabolic engineering of valuable heterologous terpenes, which creates promising new…

The Department of Agriculture National Institute of Food and Agriculture awarded the University of Tennessee $644,140 on September 15, 2026, under the Biotechnology Risk Assessment Research (BRAG) program to conduct a comprehensive ecological assessment of transplastomic potato genotypes engineered to produce terpenes.

The University of Tennessee will evaluate the environmental effects of three transplastomic potato lines producing monoterpenes, sesquiterpenes, and diterpenes respectively. Following phenotypic characterization and selection of the top-performing line, the recipient will assess impacts on target herbivores, beneficial non-target insects, neighboring crop and weed species, soil microbial communities, and soil physicochemical properties. The assessment will support regulatory decision-making on safe agricultural deployment of terpene-producing potato varieties developed through plastid genetic engineering, a platform that enables strong transgene expression without compromising plant phenotype.

The project runs through September 14, 2029, with work performed at the University of Tennessee's Agricultural Research Division in Knoxville, Tennessee. The award supports NIFA's BRAG priority area examining the effects of genetically engineered organisms relative to non-engineered organisms within production systems, with emphasis on understanding unintended ecological effects on microbes, animals, and related species to inform regulatory agencies.

A recent study in plastid genetic engineering from the PDS' laboratories has greatly advanced chloroplast metabolic engineering of valuable heterologous terpenes, which creates promising new opportunities to enhance crop resilience to natural enemies and abiotic stresses. First, the PDS developed a major innovation in solanum tuberosum (potato) plastid engineering by combining a novel site-specific transformation vector with endogenous plastid regulatory elements, enabling strong transgene expression without compromising plant phenotype. Second, this platform was successfully used to express valuable terpene-producing genes in chloroplasts, generating transplastomic potato lines with normal growth and strong potential as improved traits. Before these novel lines can be safely released, a rigorous environmental risk assessment is essential. This project will evaluate the ecological effects of three transplastomic potato genotypes producing monoterpenes, sesquiterpenes, and diterpenes respectively that are already available in the PDS' laboratories. Following comprehensive phenotypic characterization and selection of the top-performing line, we will assess effects on target herbivores, beneficial non-target insects, neighboring crop and weed species, soil microbial communities, and soil physicochemical properties. By delivering this comprehensive ecological assessment, this study will support safe agricultural use of terpene-producing transplastomic potato varieties. This project is strongly aligned with the USDA brag priority area, effects of GE organisms relative to non-GE organisms in the context of production systems, particularly its emphasis on understanding and informing regulatory agencies on unintended ecological effects of GE organisms to microbes, animals, and related species.