Programmed cell death (PCD) is a collective term for diverse processes causing an actively induced, tightly controlled cellular suicide. PCD has a multitude of functions in the development and health of multicellular organisms. In comparison to intensively studied forms of animal PCD such as apoptosis, our knowledge of the regulation of PCD in plants remains limited. Despite the importance of PCD in plant development and as a response to biotic and abiotic stresses, the complex molecular networks controlling different forms of plant PCD are only just beginning to emerge. With this review, we provide an update on the considerable progress that has been made over the last decade in our understanding of PCD as an inherent part of plant development. We highlight both functions of developmental PCD and central aspects of its molecular regulation.

Flowers have a species-specific functional life span that determines the time window in which pollination, fertilization and seed set can occur. The stigma tissue plays a key role in flower receptivity by intercepting pollen and initiating pollen tube growth toward the ovary. In this article, we show that a developmentally controlled cell death programme terminates the functional life span of stigma cells in Arabidopsis. We identified the leaf senescence regulator ORESARA1 (also known as ANAC092) and the previously uncharacterized KIRA1 (also known as ANAC074) as partially redundant transcription factors that modulate stigma longevity by controlling the expression of programmed cell death-associated genes. KIRA1 expression is sufficient to induce cell death and terminate floral receptivity, whereas lack of both KIRA1 and ORESARA1 substantially increases stigma life span. Surprisingly, the extension of stigma longevity is accompanied by only a moderate extension of flower receptivity, suggesting that additional processes participate in the control of the flower's receptive life span.