The subject invention concerns materials and methods for increasing and/or improving photosynthetic efficiency in plants, and in particular, C3 plants. In particular, the subject invention provides for means to increase the number of bundle sheath (BS) cells in plants, to improve the efficiency of photosynthesis in BS cells, and to increase channels between BS and mesophyll (M) cells. In one embodiment, a method of the invention concerns altering the expression level or pattern of one or more of SHR, SCR, and/or SCL23 in a plant. The subject invention also pertains to genetically modified plants, and in particular, C3 plants, that exhibit increased expression of one or more of SHR, SCR, and/or SCL23. Transformed and transgenic plants are contemplated within the scope of the invention. The subject invention also concerns methods for increasing expression of photosynthetically important genes in a plant, wherein one or more genes of interest are operably linked with a plant SHR, SCR or SCL23 promoter sequence and expressed in a plant.