Maintenance Mechanism of Plant Shoot Apex Cell Arrangement by WUSCHEL and CLAVATA Genes

Throughout their life cycle, plants are capable of forming organs by differentiating from special tissues called meristems. The shoot apical meristem (SAM) produces all above ground organs, such as leaves, axillary shoots, and flowers, through the continuous regeneration of stem cells. A delicate balance exists between stem cell regeneration and differentiation. Stem cell homeostasis in the SAM is maintained by a precise and dynamic negative feedback loop established through WUSCHEL and CLAVATA signalling. There is an important correlation between WUS, which preserves stem cell identity, and CLV, which inhibits meristem overgrowth, in plant development. While the WUS protein moves upward, activating CLV3 expression, the CLV3 signalling protein moves downward, suppressing WUS, creating a dynamic equilibrium. The WUS-CLV feedback cycle contributes to the morphologic integrity and preservation of the plant’s vegetative and generative developmental stages. This review aims to clarify the genetic regulatory mechanisms that play a role in maintaining stem cell identity and limiting meristem size during plant development and to evaluate the functional significance of the WUS-CLV interaction in SAM. In addition to its primary role in developmental morphogenesis, this pathway holds agronomic importance in terms of organ number and related yield parameter.