AGROBACTERIUM ‐MEDIATED GENETIC TRANSFORMATION IN THE MACROSCOPIC MARINE RED ALGA PORPHYRA YEZOENSIS

Cheney, D. 1 , Metz, B. 1 , & Stiller, J. 21 Biology Department, Northeastern University, Boston, MA 02115 USA; 2 Department of Biology, East Carolina University, Greenville, NC 27858 USA Amongst marine algae, stable genetic transformation has only been accomplished in a few unicellular species (i.e. a few diatom and dinoflagellate species). We report on the stable genetic transformation of a multicellular marine red alga or seaweed, Porphyra yezoensis. Porphyra, also known as nori, which is one of the most widely eaten and cultivated seaweeds in the world. It is also one of the most ancient seaweeds and multicellular eukaryotes that exists today, being at least 500 million years old. Our method of gene transfer is unusual in that it utilizes Agrobacterium tumefaciens, which has not heretofore been used to transform any alga. Transformation has been confirmed using both GUS (with and without an intron) and GFP reporter genes coupled to either a heterologous cauliflower mosaic virus (CaMV) 35S promoter gene or one of two homologous reporter genes (RPB1 and GAPDH). Transgene expression has been observed in primary transformants for more than an eight‐month period, as well as in progeny through the T1 and T2 generations. Evidence of stable genetic transformation will be presented. This gene transfer system permits for the first time the study of red algal promoter gene structure and function. (Supported by NSF)