Reception closed: Ethylene control of stigma longevity and programmed cell death

Non-pollinated flowers have a species-specific life span, which ends by wilting and death of floral organs, and loss the flower’s potential to produce a fruit and seeds. Though much research has been dedicated to flower senescence, we still know only little of the intricate molecular network that controls this process. With this project, we want connect the well-known plant hormone ethylene controlling flower senescence and the process of age-induced programmed cell death (PCD), which is the endpoint of senescence in floral organs. In the model plant Arabidopsis thaliana we recently confirmed that ethylene is a lifespan-regulator of the floral stigma, which is a specialized floral organ for pollen reception and crucial for effective pollination and seed set. On the basis of a recently generated transcriptome profile over different stages of stigma senescence, we aim to uncover novel nodes and edges in the regulatory network downstream of ethylene signaling and upstream of PCD execution. To this end, we will use state-of the art bioinformatics and laboratory approaches to identify stigmaexpressed genes that are activated or repressed by ethylene signaling, and transcriptional regulators that are responsible for induction of a group of recently discovered PCD marker genes in the stigma. We hope thus to find a connection between the upstream ethylene signal and the downstream PCD response, and key regulatory mechanisms that determine stigma longevity in flowering plants.