Described are nucleic acid molecules encoding basal endosperm transfer cell layer (BETL) specific proteins as well as regulatory sequences which naturally regulate the expression of such nucleic acid molecules. Vectors comprising said nucleic acid molecules, wherein the nucleic acid molecules are operatively linked to regulatory elements allowing expression in prokaryotic and/or eukaryotic host cells as well as proteins encoded by said nucleic acid molecules, antibodies to said proteins and methods for their production are provided. Described are also recombinant DNA molecules and vectors comprising said regulatory sequences as well as host cells transformed therewith. Furthermore, kits and diagnostic compositions comprising the aforementioned nucleic acid molecules, proteins, antibodies, regulatory sequences, recombinant DNA molecules and vectors as well as antibodies are provided. Also provided are methods for the identification of compounds being capable of activating or inhibiting the expression of BETL specific genes. Furthermore, transgenic plant cells, plant tissue and plants containing the above-described nucleic acid molecules, regulatory sequences, recombinant DNA molecules and vectors as well as the use of the aforementioned nucleic acid molecules, regulatory sequences, recombinant DNA molecules, vectors, proteins, antibodies, peptides and/or compounds identified by a method of the invention in plant cell and tissue culture, plant breeding and/or agriculture are described.