Rubisco production in maize mesophyll cells through ectopic expression of subunits and chaperones

Abstract C4 plants, such as maize, strictly compartmentalize Rubisco to bundle sheath chloroplasts. The molecular basis for the restriction of from more abundant mesophyll chloroplasts is not fully understood. Mesophyll transcribe large subunit gene and, when normally quiescent transcription nuclear small family overcome by ectopic expression, still do accumulate measurable Rubisco. Here we show that a combination five ubiquitin promoter-driven transgenes expressed in maize leads accumulation assembled These encode and subunits, assembly factors 1 2, factor Bundle defective 2. In these accumulates cells, appears be into holoenzyme capable binding substrate analog CABP (carboxyarabinitol bisphosphate). Isotope discrimination assays suggest, however, participating carbon assimilation most probably due lack ribulose 1,5-bisphosphate and/or activase. Overall, this work defines minimal set planta may help lead methods regulating pathway.