Plant cell walls are essential for a plant’s growth, development, and structural integrity towards biological and environmental factors. Cellulose is one of the main structural components in the primary cell walls of plants. This biopolymer is synthesized at the plasma membrane by cellulose synthase complexes (CSC), which are made up of cellulose synthase proteins (CESA). Previous research has shown that CSC complexes and CESA proteins are found in the plasma membrane during synthesis; however, the assembly and trafficking of these complexes to the membrane are poorly understood. In this study, we investigate the role Tca17, a TRAPPII and TRAPPIII specific subunit, may play in regulating CSC dynamics and compare its subcellular dynamics to Trs85, a TRAPPIII specific subunit. We found that tca17 mutants had reduced seven-day-old dark-grown hypocotyls and a lower crystalline cellulose content in four-day-old hypocotyls. The YFP-CESA6 density at the plasma membrane in prc1-1 tca17 was not affected in 2.5-day-old etiolated hypocotyls, unlike the increase in YFP-CESA6 density observed in prc1- 1 trs85-1. Overall, our findings suggest that Tca17 is involved in cellulose synthesis at the plasma membrane, however, the role it plays may be different and independent of Trs85.
