Some plants require winter season for flowering, which is called vernalization, and it is a key agriculture trait for crop breeding. Mechanism with molecular module for remembering winter is a key base for the molecular design of crop breeding.
Recently, a research group led by CHONG Kang from the Institute of Botany of the Chinese Academy of Sciences (IBCAS) published a review article entitled "Remembering winter through vernalization" in Nature Plants.
Based on the authors' achievements on the function of crosstalk between phosphorylation and O-GlcNAcylation on the key proteins and epigenetic modifications of the key gene VRN1 in wheat vernalization, a fresh viewpoint for vernalization sensing as well as the potential evolutionary origins of vernalization in various species were arisen and discussed in the review article.
The epigenetic-regulation and memory mechanism for vernalization have been clarified in the dicots Arabidopsis and temperate grasses wheat, barley and Brachypodium.
The article also sketches out the molecular genetic framework for vernalization in various species. It summarizes the latest regulatory and sensing mechanisms of vernalization, and puts forward future research directions for vernalization and prospects for its applications in molecular breeding strategies.
There is a distinct diversity between the genetic pathways of vernalization-mediated flowering in Arabidopsis and temperate grasses (such as wheat, barley and Brachypodium distachyon) (Figure 1). Winter cereals varieties that require vernalization express various regulatory genes in response to vernalization to adjust floral initiation, such as VRN1, VRN2 and VRN3.
VRN1, encoding an AP1-like MADS-box transcription factor, is induced by vernalization and plays a crucial role in the floral transition.
VER2, induced by vernalization, encodes a jacalin-like lectin with high affinity for galactose and GlcNAc. VER2 can interact with the glycine-rich RNA-binding protein GRP2 to move GRP2 from the nucleus to the cytoplasm, which repressed the specific RNA-binding function of GRP2 to RIP3 in the first intron of VRN1 in the nucleus, resulting in high levels of VRN1 transcripts upon prolonged cold exposure (Figure 2).
And SNPs in the RIP3 motif of VRN-A1 are correlated with winter and spring growth habits in wheat, which provides a novel idea to develop wheat varieties adapting the different environments.
The study was supported by the Natural Science Foundation of China.
Figure 1. The vernalization gene-regulatory networks. (Image by IBCAS)
Figure 2. The regulatory role of O-GlcNAc signal in vernalization. (Image by IBCAS)
52 Sanlihe Rd., Xicheng District,
Beijing, China (100864)