# O-GlcNAc and phosphorylation modifications on HtL1/FBA10 regulate wheat vernalization for flowering

## TL;DR

This study reveals how sugar metabolism and epigenetic changes in wheat influence flowering time through a key gene called HtL1/FBA10.

## Contribution

The study identifies HtL1/FBA10 as a modulator of flowering time and shows how vernalization alters its modifications to regulate gene expression.

## Key findings

- Vernalization reduces phosphorylation and increases O-GlcNAcylation of HtL1/FBA10, enhancing its enzymatic activity.
- Modified HtL1/FBA10 promotes VRN1 transcription through histone acetylation regulation.
- Evolutionary analysis shows a decrease in delayed-flowering haplotype-2 of HtL1 in modern wheat varieties.

## Abstract

Vernalization-regulated flowering is vital for wheat yield and geographical distribution, and the diversity of flowering time genes is essential for the breeding of climate-resilient varieties. Sugars have long been recognized in regulating flowering; however, the intrinsic connection between carbohydrate metabolism and vernalization response remains largely unexplored. Here, we identify a fructose 1,6-bisphosphate aldolase (FBA) encoding gene, HtL1/FBA10, as a modulator of heading time variation based on a genome-wide association study utilizing wheat core germplasm collections. Evolutionary analysis shows a decrease in the proportion of haplotype-2 of HtL1, which is linked to delayed flowering, in Chinese and American wheat varieties compared to landraces. Vernalization reduces HtL1/FBA10 phosphorylation levels and  increases  its O-GlcNAcylation, which in turn enhances its enzymatic activity and facilitates VERNALIZATION 1 (VRN1) transcription by regulating histone acetylation at the VRN1 locus. Our findings provide mechanistic insights into the interplay between glucose metabolism and the epigenetic regulation of vernalization in winter wheat.

This study shows that the wheat major QTL gene-encoded sugar metabolic enzyme HtL1/FBA10 undergoes vernalization-induced dynamic changes in O-GlcNAcylation and phosphorylation, enhancing its enzymatic activity and increasing VRN1 gene expression for flowering.