An efficient transient expression system for study of endosperm development in plants

As the edible part of cereal grains, endosperm supplies over 60 % of the nutritional needs of humanity. Endosperm development is a precisely regulated complex process. However, the absence of an effective and high-through tool for the functional validation poses a significant constraint on research of endosperm development. Here, we established a simple and rapid Agrobacterium-mediated transient expression system for endosperm research. This study used sweet corn as experimental materials. We systematically examined various factors affecting transient expression efficiency. Kernels from the sweet corn cultivar 7401, harvested during the picking period, were particularly suitable for transient expression. The reporter protein eGFP can be detected as early as 3 days after Agrobacterium infiltration (DAI), and exhibited stable expression up to 10 DAI. By utilizing the Agrobacterium strain GV3101 equipped with helper plasmids, we achieved a remarkable increase in transformation efficiency, reaching 100 %. Furthermore, we developed a phenotype index method that allows for the precise and efficient identification of a gene's functional effects in sweet corn kernels. Consequently, this study introduces a valuable tool to facilitate efficient and sustained gene expression, which is essential for conducting large-scale endosperm functional genomics research.