Chinese Bulletin of Botany ›› 2018, Vol. 53 ›› Issue (1): 1-4.DOI: 10.11983/CBB17234

• COMMENTARY •     Next Articles

Mechanism of The “Pioneer” Transcription Factor LEC1 in Resetting Vernalized State in Early Embryos

Shujuan Xu1,2, Kang Chong1,2*   

  1. 1Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2University of the Chinese Academy of Sciences, Beijing 100049, China
  • Received:2017-12-04 Accepted:2018-01-10 Online:2018-01-01 Published:2018-08-10
  • Contact: Kang Chong

Abstract: Flowering is an important process for plants to switch from vegetative to reproductive phase. Vernalization is a process whereby plants acquire the ability to flower after exposure to a prolonged cold temperature. In Arabidopsis, inhibitor-type transcription factor FLOWERING LOCUS C (FLC) is a critical point in vernalization-mediated flowering pathway. Previous studies in Arabidopsis thaliana revealed that two homologous epigenome readers, VAL1 and VAL2, re- cognize a cis DNA element in the nucleation region for Polycomb group (PcG) silencing at the key floral repressor FLC, engaging Polycomb group proteins to induce epigenetic silencing of FLC by histone 3 lysine trimethylation (H3K27me3) during vernalization. This silencing is maintained in subsequent growth and development under normal temperature, namely vernalization memory. How to delete vernalization memory in the next generation to de novo activate FLC expression, preventing the offspring from flowering before or during winter, is not clear. Recently, Chinese scientist have found that a seed-specific transcription factor LEAFY COTYLEDON1 (LEC1) functions in deleting vernalization memory and reactivating the expression of FLC in the pro-embryo by resetting the chromatin states from the silenced state (marked by H3K27me3) to an active state (H3K36me3). This study provides important understanding of molecular and genetic mechanisms for flowering control by vernalization, and a novel strategy to genetically manipulate crop flowering times for the benefit of agricultural production, which is a great breakthrough of this field.

Key words: chromatin reprogramming, epigenetic regulation, vernalization, vernalization memory