The regulation of plant organ initiation, identity and morphogenesis is crucial for the formation of a functional plant. It has been established that both hormonal and genetic networks are crucial for organ development and one of our aims is to identify central genetic and hormonal pathways. We are specifically interested in the developmental regulation of one of the most complex and important plant organs, the female gynoecia / fruit. In addition, we aim to identify evolutionary changes / conservations in the regulation of organ development.
All flowering plants produce fruits. Whereas we often think of fruits as nutritious, their function is to protect and nurse the seeds that will give rise to the next generation. Fruits occur in extremely diverse forms. Underlying this enormous biodiversity, a common set of regulatory mechanisms control fruit development in diverse species. We know several key genetic regulators of fruit development, and some of these relate to the synthesis, transport or signal transduction of the plant hormone auxin. Our aim is to study auxin dynamics and the interaction of this hormone with genetic networks, in order to achieve an integrated view of fruit development. We have so far identified key genetic regulators of auxin dynamics during gynoecium / fruit development.
Another aim is to study the interplay between controlled auxin biosynthesis and polar auxin transport in early cotyledon and leaf development. We are, together with Professor Jim Mattsson (Simon Fraser University, Vancouver) mapping the spatiotemporal activity of these processes in young cotyledon and leaf primordia.
The origin of land plants was one of the most important evolutionary events in the earth’s history. The earliest land plants were likely haploid-dominant organisms in many ways similar to extant bryophytes (mosses). Most available data suggest that the evolution of the diploid multi-cellular sporophyte dominating the higher plant life cycle involved the recruitment of existing gametophytic developmental programs of the haploid early bryophytes. Our aim is to study the role and genetic regulation of the plant hormone auxin during organ development in the haploid gamtetophyte of the moss Physcomitrella patens, and to make comparisons with the identified networks in angiosperms. We have shown that homologous regulators affect auxin biosynthesis during organ development in moss and angiosperms, and that auxin is crucial for organ morphogenesis in both lineages.
Larsson E, Roberts CJ, Claes AR, Franks RG, Sundberg E (2014) Polar Auxin Transport is Essential for Medial versus Lateral Tissue Specification and Vascular-mediated Valve Outgrowth in Arabidopsis Gynoecia. Plant Physiology 166:1998-2012
Viaene T, Landberg K, Thelander M, Medvecka E, Pederson ERA, Feraru E, Cooper ED, Karimi M, Delwiche C, Ljung M, Geisler M, Sundberg E*, Friml J* (2014) Directional auxin transport mechanisms in early diverging land plants. Current Biology 24:2786-91 * senior co-authors
Landberg K, Pederson ERA, Viaene T, Bozorg B, Friml J, Jönsson H, Thelander M, Sundberg E (2013) The moss Physcomitrella patens reproductive organ development is highly organized, affected by the two SHI/STY genes and by the level of active auxin in the SHI/STY expression domain. Plant Physiology 162:1406-1419.
Eklund DM, Ståldal V, Valsecchi I, Cierlik I, Eriksson C, Hiratsu K, Ohme-Takagi M, Sundström J, Thelander M, Ezcurra I and Sundberg E (2010) The Arabidopsis thaliana STYLISH1 protein acts as a transcriptional activator regulating auxin biosynthesis. Plant Cell 22:349-363
Eklund DM, Thelander M, Landberg K, Ståldal V, Nilsson A, Johansson M, Valsecchi I, Pederson ERA, Kowalczyk M, Ljung K, Ronne H and Sundberg E (2010). Homologues of the Arabidopsis thaliana SHI/STY/LRP1 genes control auxin biosynthesis and affect growth and development in moss Physcomitrella patens. Development 137:1275-1284