Characterizing  Nopaline Synthase Promoter Variants  for Use in Plant Synthetic Biology

Plants are a significant potential platform for synthetic biology applications. Quantitatively characterizing genetic parts for use in synthetic circuitry designed specifically for plant applications is an ongoing process in plant synthetic biology laboratories. We have developed a methodology to characterize and quantitatively test genetic parts in isolated plant cells. We used this methodology to characterize a variant library of the Nopaline Synthase promoter (PNOS), an Agrobacterium tumefaciens derived promoter commonly used in plant genetic engineering applications due to its constitutive activity in plant cells. Screening of the PNOS library using flow cytometry yielded a collection of variant PNOS with a range of transcriptional strengths that can be used to tune synthetic genetic circuitry in plants.