Protein disulfide isomerase that may be required for proper pollen development, ovule fertilization and embryo development. Catalyzes the rearrangement of -S-S- bonds in proteins. A number of isoforms are produced. According to EST sequences. Widely expressed. During flower development, expressed at early stage in inner and outer integuments, and nucellar cells. Later, expressed in the integument cells but not in the embryo sac. In the mature ovule, highly expressed in the micropylar region. After fertilization, expressed in the seed integuments but not in the embryo. By chemically-induced ER stress response. Smaller siliques and reduced seed set. Disrupted pollen tube guidance. Belongs to the protein disulfide isomerase family.