Provided are recombinant constructs comprising DNA sequences encoding
enzymes effective in altering the biosynthesis and accumulation of sterol
compounds and tocopherols in transgenic plants. Also provided are methods
of using such constructs to produce transgenic plants, seeds of which
contain elevated levels of sitostanol and/or sitostanol esters, and
.alpha.-tocopherol, as well as reduced levels of campesterol and
campestanol and their corresponding esters. These seeds also contain the
novel sterol brassicastanol. Oil obtained from seeds of such transgenic
plants is also provided. This oil can be used to prepare food and
pharmaceutical compositions effective in lowering the level of low
density lipoprotein cholesterol in blood serum. In addition, novel DNA
sequences encoding plant steroid 5.alpha.-reductases are also disclosed.
