Transient Oleosomes (Lipid Bodies) in Early Differentiation of Sesbania rostrata Nodules

Abstract

Transient occurrence of oleosomes (lipid bodies) was observed during early stages of nodule differentiation in Sesbania rostrata. In stem nodules the first appearance of oleosomes in the infected cells was noted 8 d after inoculation of root primordia of the stem. These nodules were at the early stages of differentiation, white and <1 mm in diameter. At this stage the oleosomes were found in spherical/ovoid infected cells showing a single bacteroid in the symbiosomes. The elongated and larger infected cells revealed no or very rare presence of oleosomes; the symbiosomes were enlarged containing seven to eight bacteroids. In mature pink nodules as many as 17 bacteroids were counted within the symbiosomes. One of the unique features of the stem nodule oleosome is its large size, which could measure up to 8-10 μm in diameter. The increased size is thought to result from an oversupply of photosynthate from the chlorophyllous nodule parenchyma and the other chlorophyllous aerial tissues. These oleosomes are po...