SEQUENCE-ANALYSIS OF 2 NEW MEMBERS OF THE MAJOR LATEX PROTEIN GENE FAMILY SUPPORTS THE TRIPLOID-HYBRID ORIGIN OF THE OPIUM POPPY

Latex from the opium poppy (Papaver somniferum) contains an abundant g roup of laticifer-specific, low-molecular-weight polypeptides called t he major latex proteins (MLPs). MLPs are encoded by a family of nine g enes which can be divided into two distinct subfamilies based on DNA g el blot analysis. This report describes two new members of the MLP gen e family (MLP146 and MLP149) that are physically linked and separated by approx. 5.5 kb. Comparison of their nucleotide and deduced amino-ac id sequences with those of other MLP indicates that both new MLP belon g to the MLP15 subfamily. The organization of the MLP family is consis tent with the triploid-hybrid origin of the opium poppy.