Cell differentiation and rhizoid development in seaweed

Understanding the mechanisms of polarization and patterning of cells, tissues, and organs is a central goal for developmental biologists. Embryos of angiosperms develop while still enclosed in maternal tissue, making cellular, molecular, and physiological analyses technically challenging. In contrast, harvesting gametes from broadcast spawning seaweeds such as Fucus and Dictyota is straightforward and results in large populations of synchronously developing cells. Additionally, the large size of the eggs facilitates visualization of internal structures and experimental manipulation of the zygotes.

  • Bogaert KA*, Zakka EE, Coelho SM, De Clerck O (2023) Polarization of brown algal zygotes. Semin Cell Dev Biol. 134, 90-102. doi: 10.1016/j.semcdb.2022.03.008
  • Bogaert KA, Beeckman T, De Clerck O* (2015) Photopolarization of Fucus zygotes is determined by time sensitive vectorial addition of environmental cues during axis amplification. Frontiers in Plant Science 6:26.
Bogaert et al. (2023) Seminars in Cell & Developmental Biology

The most frequently used model species belong to the genera Fucus and Silvetia. The difficulty of culturing these fucoid algae under laboratory conditions impedes the extensive use of gene editing, and epigenomics in this line of developmental research. In contrast, the oogamous parenchymatous Dictyota dichotoma can be cultured easily. Part of my research aims to gain deeper insights into the polarization mechanisms and the evolvability of early development in plant systems using Dictyota as the model system.

  • Bogaert KA*, Beeckman T, De Clerck O (2017) Two-step cell polarization in algal zygotes. Nature Plants 3: 16221
  • Bogaert KA*, Beeckman T, De Clerck O (2017) Egg activation-triggered shape change in the Dictyota dichotoma (Phaeophyceae) zygote is actin–myosin and secretion dependent. Annals of Botany 120: 529–538
  • Bogaert KA*, Beeckman T, De Clerck O (2016) Abiotic regulation of growth and fertility in the sporophyte of Dictyota dichotoma (Hudson) J.V. Lamouroux (Dictyotales, Phaeophyceae). Journal of Applied Phycology 28:  2915-2924.
Bogaert et al. (2022) Trends in Plant Science

For example, we demonstrated that auxin acts as a rhizoid differentiation-promoting compound in the brown alga Dictyota. Despite the long evolutionary distance and independent evolution of multicellularity, similar phenotypes emerge in mosses and brown seaweeds upon auxin addition. Conservation of the auxin transporters, PILS family suggests a putative deep homology of auxin function which has been convergently expanded.

  • Bogaert KA*, Blommaert L, Ljung K, Beeckman T, De Clerck O. (2019) Auxin function in the brown alga Dictyota dichotomaPlant Physiology 179: 280-299
  • Bogaert KA*, Blomme J, Beeckman T, De Clerck O. (2022) Auxin’s origin: do PILS hold the key? Trends in Plant Science 27: 227-236.

In contrast to broadcast spawners such as Dictyota and Fucus, kelp eggs and embryos remain physically connected to the female gametophyte after extrusion from the oogonium. Kelp aquaculture garners significant interest; however, its early development is poorly understood. By studying kelp, especially Undaria pinnatifida (wakame) and Saccharina latissima (sugar kelp), I aim to understand this mode of development and contribute to advancing sustainable seaweed aquaculture.

  • Dries E, Meyers Y, Liesner D, Gonzaga F, Becker, J, Zakka EE., Beeckman T, Coelho S, De Clerck O & Bogaert KA* (2024). Cell wall-mediated maternal control of apical-basal patterning of the kelp Undaria pinnatifida. bioRxiv, 2024-04.