title: Stable chloroplast transformation of the unicellular red alga Porphyridium species.
abstract: Red algae are extremely attractive for biotechnology because they synthesize accessory photosynthetic pigments (phycobilins and carotenoids), unsaturated fatty acids, and unique cell wall sulfated polysaccharides. We report a high-efficiency chloroplast transformation system for the unicellular red microalga Porphyridium sp. This is the first genetic transformation system for Rhodophytes and is based on use of a mutant form of the gene encoding acetohydroxyacid synthase [AHAS(W492S)] as a dominant selectable marker. AHAS is the target enzyme of the herbicide sulfometuron methyl, which effectively inhibits growth of bacteria, fungi, plants, and algae. Biolistic transformation of synchronized Porphyridium sp. cells with the mutant AHAS(W492S) gene that confers herbicide resistance gave a high frequency of sulfomethuron methyl-resistant colonies. The mutant AHAS gene integrated into the chloroplast genome by homologous recombination. This system paves the way for expression of foreign genes in red algae and has important biotechnological implications.
authors: Department of Life Sciences, Ben Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors: Miri
authors: M
authors: Lapidot
authors: Dina
authors: D
authors: Raveh
authors: Alex
authors: A
authors: Sivan
authors: Shoshana Malis
authors: SM
authors: Arad
authors: Michal
authors: M
authors: Shapira
mesh_terms: D000095:Acetolactate Synthase / Q000235:genetics / Q000378:metabolism; D015139:Blotting, Southern; D002736:Chloroplasts / Q000187:drug effects / Q000235:genetics*; D006540:Herbicides / Q000494:pharmacology; D030781:Organisms, Genetically Modified; D000461:Rhodophyta / Q000187:drug effects / Q000235:genetics*; D013453:Sulfonylurea Compounds / Q000494:pharmacology; D014170:Transformation, Genetic
chemical_list: D006540:Herbicides; D013453:Sulfonylurea Compounds; D000095:Acetolactate Synthase; C042031:sulfometuron methyl