The role of auxin for reproductive organ patterning and development

Abstract

The reproductive structures of flowering plants consist of the gynoecium harboring the female gametophyte (embryo sac) inside one or many ovules as well as stamen and anthers containing the male gametophytes (pollen). The coordinative development and patterning of these structures from undifferentiated flower meristems into gametophyte-containing reproductive organs constitutes the most complex developmental process in plants. Auxin represents a master player as it acts not only as a local morphogenetic trigger in flower organ primordia formation, but also in concert with other hormones during further development, patterning, and function of both reproductive organs. Most of our knowledge about the role of auxin for plant reproduction was obtained from the study of mutants in the Brassicaceae model plant Arabidopsis thaliana. Especially mutants defective in biosynthesis and perception of the hormone as well as in auxin-regulated transcriptional response have been analyzed. Although very little is known about the role of auxin during reproduction in crop plants, we will briefly report on reproductive structures in the economically important grass family and highlight auxin signaling data in other species when available.