Sterol profile determind by GC-MS of <i>erg7</i> expressing a tobacco cycloartenol synthase CAS1.

<p><b>A</b>, TIC of a total unsaponifiable extract of <i>erg7</i> transformed with a void vector. <b>B</b>, TIC of a total unsaponifiable extract of <i>erg7::NtCAS1</i>. <b>C</b>, 9β,19-cyclopropylsterol biosynthetic pathway in yeast. Compounds are: <b>1</b>, 2,3-oxidosqualene; <b>2</b>, ergosterol; <b>3</b>, cycloartenol; <b>4</b>, 31-norcycloartenol; <b>5</b>, 24-dehydropollinastanol; <b>6</b>, cycloeucalenol; <b>7</b>, 24-methylene pollinastanol. Compounds are identified according to their mass spectra and to those of authentic standards for 3, 6, and 7 purified from plant material as previously described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109156#pone.0109156-Lovato1" target="_blank">[25]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109156#pone.0109156-Men1" target="_blank">[26]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109156#pone.0109156-Wang2" target="_blank">[44]</a>. Peaks that are not numbered are not sterols.