SDA Growth Medium w/o LEU

Principle and Interpretation

SDA Growth Medium w/o LEU is a synthetic defined agar media for the selective growth of Saccharomyces cerevisiae. Synthetically Defined media known as Yeast Nitrogen Base Media for the growth of yeast cells were first cited by Wickerham (1, 2). SDA Growth Medium w/o LEU includes a yeast nitrogen base along with ammonium sulfate, and dextrose as the carbon source, which is further supplemented with various amino acids except leucine which makes it a dropout growth medium for yeast cells. A leucine auxotrophic yeast mutant cannot grow on this media but a wild-type or a leucine prototrophic yeast strain can grow. The leucine auxotroph has a mutation in a gene (e.g. LEU2) of the leucine synthesis pathway and this mutant strain will grow in this medium if leucine is supplied from outside e.g. from a plasmid which contains LEU2 gene (3). For this purpose, a leu2 mutant strain of S. cerevisiae is transformed with a LEU2 containing plasmid and the transformants can be selected by growing the cells on SDA Growth Media w/o LEU. Hence this medium is very useful in molecular genetics.