FIG. 2.

Immunohistochemical localization of NolX. Six-day-old cowpea nodules (A, B, and D) and 8-day-old soybean nodules (C) were embedded in paraffin, processed for immunohistochemical localization, and counterstained with hematoxylin. Paraffin-embedded sections were treated with NolX-specific antiserum (A, C, and D) or preimmune serum (B). Note the brown color (arrows) indicative of the specific labeling of NolX on the infection threads (IT) of both cowpea (A) and soybean (C) nodules. No specific labeling was detected in cowpea nodules formed by USDA257Mu78 (nolX mutant) (D).