Peroxisomes of soybean (Glycine max) root nodule vascular parenchyma cells contain a “nodule—specific” urate oxidase

Abstract

The cortex of soybean (Glycine max L. cv. Centennial) nodules contain an organellerich layer of vascular parenchyma tissue, which encircles the elaborate vascular tissue of the nodule. Peroxisomes with small, electron‐opaque nucleoids are found in the vascular parenchyma cells. Positive cytochemical staining for catalase (EC 1.11.1.6) confirms their morphological identification as peroxisomes. Activities of both glycolate oxidase (EC 1.1.3.1) and urate oxidase (EC 1.7.3.3) were detected cytochemically in these peroxisomes. Nodule‐specific urate oxidase was localized principally in the nucleoid region of these vascular parenchyma peroxisomes, as indicated by immunogold labelling using antibodies against nodulin‐35, the nodule‐specific urate oxidase. The density of urate oxidase immunogold labelling in the vascular parenchyma peroxisome nucleoid is similar to that of the more well‐characterized interstitial cell peroxisomes of the infected zone. These results show that the induction of nodule‐specific urate oxidase may be induced in tissue outside of the infected zone.