10. In Arabidoposis gene responsible for formation shoot meristem is
(1) Leafy                                                       (2) Agamous
(3) Clavata                                                    (4) Wus

Introduction

Shoot meristem formation is critical for plant growth and organogenesis. In Arabidopsis, the transcription factor encoded by the gene WUSCHEL (WUS) is essential for maintaining the stem cell population in the shoot apical meristem (SAM) and ensuring its proper structure and function throughout development.

Role of WUSCHEL Gene in Shoot Meristem Development

• WUS is expressed specifically in a group of cells known as the organizing center within the central zone of the shoot apical meristem.​

• It maintains the stem cell population by promoting stem cell identity and regulating the balance between stem cell renewal and differentiation.​

• Mutations in WUS lead to premature termination of shoot meristems, failure to maintain stem cells, and defects in shoot organ formation.​

• WUS protein moves from the organizing center to stem cells, where it activates the expression of signaling molecules such as CLAVATA3 (CLV3), which in turn represses WUS expression, forming a feedback loop to regulate meristem size and function.​

Interaction with Other Genes

• WUS acts upstream of genes like AGAMOUS (AG) that pattern floral organ identity.​

• The dynamic regulation of WUS and its feedback with CLV3 ensures the homeostasis of the meristem stem cell niche.​

• Other genes like LEAFY and CLAVATA are also involved in shoot development but WUS is the key regulator of meristem maintenance.​

Importance of WUS in Plant Development

• WUS is crucial for initiating and sustaining the shoot apical meristem during embryogenesis and throughout post-embryonic development.​

• Ectopic expression of WUS can induce somatic embryogenesis and formation of new meristems, demonstrating its role as a master regulator.​

Summary Table: Key Features of WUSCHEL Gene

Conclusion

WUSCHEL is the essential gene responsible for the formation and maintenance of the shoot meristem in Arabidopsis. It regulates stem cell identity through a tightly controlled feedback mechanism with CLAVATA signaling, ensuring proper meristem function and shoot development.