Analysis of programmed cell death in wheat endosperm reveals differences in endosperm development between cereals

Although maize endosperm undergoes programmed cell death during its develop ment, it is not known whether this developmental feature is common to cerea ls or whether it arose inadvertently from the selection process that result ed in the enlarged endosperm of modern maize. Examination of wheat endosper m during its development revealed that this tissue undergoes a programmed c ell death that shares features with the maize program but differs in some a spects of its execution. Cell death initiated and progressed stochastically in wheat endosperm in contrast to maize where cell death initiates within the upper central endosperm and expands outward. After a peak of ethylene p roduction during early development, wheat endosperm DNA underwent internucl eosomal fragmentation that was detectable from mid to late development. The developmental onset and progression of DNA degradation was regulated by th e level of ethylene production and perception. These observations suggest t hat programmed cell death of the endosperm and regulation of this program b y ethylene is not unique to maize but that differences in the execution of the program appear to exist among cereals.