Graduate Student The University of Mississippi oxford, Mississippi
Body of Abstract: Organ boundaries play crucial roles in coordinating the growth and development of plant organs. Within the developing gynoecium, an organ boundary known as the carpel margin meristem gives rise to a set of reproductive tissues that include the ovules, septum, transmitting tract, style and stigma. Previous studies have shown that disruption of organ boundary gene function is associated with female sterility. For instance, loss of the redundant CUC1 and CUC2 NAC transcription factors prevents septum fusion and interferes with ovule development. Our studies of the STM and ATH1 homeodomain transcription factors have shown that stm ath1 double mutant flowers lack gynoecia or produce fruit with defects in septum fusion and ovule development. To explore the interactions between STM and ATH1 with other organ boundary genes during gynoecium development, phenotypic analysis of higher order mutants is in progress. Our results to date suggest that STM activity functionally overlaps with that of CUC1, CUC2, and SPT. Each of the double mutants—stm cuc1, stm cuc2, and stm spt—produce fruit with unfused septa and ovules that fail to form seeds. These defects are more severe than those observed in the stm, cuc or spt single mutants