The Arabidopsis fruit is a dehiscent silique that basically consists of a mature ovary. Along the mediolateral axis, the ovary develops as a cylindrical species that externally comprises two valves with lateral polarity separated at the medial plane by two repla. Another tissue with lateral polarity, the valve margin, develops between valve and replum and will differentiate into the dehiscence zone. Our knowledge of the molecular mechanisms and genetic networks involved in the formation of these three pattern elements has increased greatly over the past few years. The present view on the establishment of this pattern is that the ovary reproduces the antagonistic interactions between meristem- and leaf-expressed genes. Thus, the replum displays meristematic properties and expresses meristem genes (replum factors), whereas valves express genes that work to make leaves (valve factors) and are more related to these lateral organs. Following this line of argument, a recent model puts forward that the antagonistic activities of the opposing gradients of replum and valve factors determine the territories of the ovary where replum, valve margin and valves will form. Undoubtedly, understanding these mechanisms will contribute to optimize harvest yield in crops with dehiscent fruits, providing control of seedpod shatter.