63. Which one of the following statements about LEAFY (LFY), a regulatory gene in Arabidopsis thaliana, is correct?
(1) LEAFY (LFY) is involved in floral meristem identity
(2) LEAFY (LFY) is involved in leaf expansion.
(3) LEAFY (LFY) ‘is involved in root meristem identity.
(4) LEAFY (LFY) is responsible far far-red light mediated seedling growth

Introduction

LEAFY (LFY) is a pivotal regulatory gene in Arabidopsis thaliana that controls the transition from vegetative growth to reproductive development by specifying floral meristem identity. LFY encodes a plant-specific transcription factor that activates key floral homeotic genes and triggers the developmental reprogramming necessary for flower formation.

Role of LEAFY (LFY) in Flower Development

• LFY is expressed predominantly in the shoot apical meristem during the transition phase to flowering and maintains expression in floral meristems.​

• Acting as a master regulator, LFY activates downstream genes including APETALA1 (AP1), which is crucial for floral organ identity specification.​

• LFY influences multiple aspects of floral morphogenesis, including organ number, positioning, and identity, by controlling the expression of homeotic gene complexes.​

Other Functions and Characteristics of LFY

• LFY functions as a pioneer transcription factor that can bind to target DNA sites even in closed chromatin, enabling chromatin remodeling and activation of flower-specific genes.​

• It is essential for initiating the developmental switch from inflorescence to floral meristem, distinguishing flower primordia from vegetative shoots.​

Contrast with Other Functions

• LFY is not involved in leaf expansion, root meristem identity, or far-red light-mediated seedling growth.​

• These functions are regulated by other gene networks and environmental pathways.

Summary Table: LEAFY Gene Attributes

Conclusion

LEAFY (LFY) gene in Arabidopsis is primarily responsible for specifying floral meristem identity and initiating flower development, making statement (1) the correct choice.