Uncovering C 4 -like photosynthesis in C 3 vascular cells

Abstract

In C 4 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 C 4 plants, relatively little is known about photosynthesis in C 3 plant veins, which differs substantially from that in C 3 mesophyll cells. In this review we highlight the specific photosynthetic machinery present in C 3 vascular cells, which likely evolved prior to the divergence between C 3 and C 4 plants. The associated primary processes of carbon recapture, nitrogen transport, and antioxidant metabolism are discussed. This review of the basal C 4 photosynthesis in C 3 plants is significant in the context of promoting the potential for biotechnological development of C 4 -transgenic rice crops.