Uncovering C4-like photosynthesis in C3 vascular cells

In C4 plants, the vascularization of the leaf is extended to include a ring of photosynthetic bundle sheath cells, which have essential and specific functions. In contrast to the substantial knowledge of photosynthesis in C4 plants, relatively little is known about photosynthesis in C3 plant veins, which differs substantially from that in C3 mesophyll cells. In this review we highlight the specific photosynthetic machinery present in C3 vascular cells, which likely evolved prior to the divergence between C3 and C4 plants. The associated primary processes of carbon recapture, nitrogen transport, and antioxidant metabolism are discussed. This review of the basal C4 photosynthesis in C3 plants is significant in the context of promoting the potential for biotechnological development of C4-transgenic rice crops.