Establishment and characterization of a maize Hi-II endosperm culture

An in vitro continuous endosperm callus culture derived from developing endosperm of transformation-amenable maize Hi-II genotype was obtained. The endosperm callus was composed of cells that differentiated into aleurone-like and starchy endosperm-like cell types. This callus has been maintained for 4?yr. Endosperm callus cells transcribe and produce zein proteins at a level similar to developing endosperm tissue. Starchy endosperm cells of the endosperm callus displayed active starch biosynthetic activity. The dual cell physiology of this culture limited the utility of the cell line for promoter analysis and transient assays of gene expression in the current culture conditions. However, because such cell line can be readily initiated and easily maintained for a long period of time, it provides an alternative tool for analysis of transgene expression in endosperm callus derived from transgenic maize lines in Hi-II background.