Genes encoding sterol delta-14 reductase in plants

An isolated polynucleotide comprising:

• (a) a nucleotide sequence encoding a sterol delta-14 reductase polypeptide, wherein the polypeptide has an amino acid sequence of at least 85% sequence identity, based on the Clustal method of alignment wherein the default parameters for multiple alignment are GAP PENALTY=10, GAP LENGTH PENALTY=10 and default parameters for pairwise alignments are KTUPLE 1, GAP PENALTY=3, WINDOW=5 and DIAGONALS SAVED=5, when compared to one of SEQ ID NO:
• 6 or 8, or
• (b) a complement of the nucleotide sequence, wherein the complement and the nucleotide sequence consist of the same number of nucleotides and are 100% complementary.