Programmed chloroplast destruction during leaf senescence involves 13-lipoxygenase (13-LOX)

Abstract

Significance Mammals including humans use highly specific pathways for tissue differentiation. One such pathway is operative in reticulocytes and involves the programmed destruction of the cell’s organellar complement by 15-lipoxygenase (15-LOX), which oxygenates polyunsaturated membrane fatty acids and provokes organelle leakage. As we report here, plants make use of a similar LOX pathway to degrade their chloroplasts during leaf senescence. The enzyme involved is a 13-LOX with unique positional specificity and molecular terms. Because 15-LOX and 13-LOX pathway products likewise operate in biological defense, a mechanism of cross-kingdom conservation of pathway regulation and function was uncovered for multicellular eukaryotes.