Wheat (Triticum aestivum) is an important global food crop whose productivity is highly dependent on nitrogen fertilizer application. The need to improve nitrogen use efficiency (NUE) in wheat is evident as a countermeasure to the negative effects of excessive nitrogen application. Effective nitrate absorption, a key factor in NUE, is closely linked to root system architecture. However, there remains a notable research gap regarding the establishment of wheat root morphology under varying nitrogen conditions, particularly in the areas of epigenomics and transcriptional regulation.

Led by Prof. XIAO Jun at the Institute of Genetics and Developmental Biology (IGDB) of the Chinese Academy of Sciences, researchers delved into the epigenomic landscape of two representative wheat cultivars-Kenong 9204 (KN9204) and Jing 411 (J411)-known for their divergent responses to low nitrogen (LN) conditions, indicative of different NUE.

The researchers unveiled the cultivar specificity of distal H3K27ac regulatory regions, shedding light on their pivotal role in shaping distinct agronomic traits, such as root morphology.

In particular, they underscored that differences in histone modifications, rather than variations in DNA sequences, significantly influence the disparate expression patterns of genes related to nitrogen metabolism in these cultivars.

The dynamic changes in histone modifications (H3K27ac and H3K27me3) emerge as key drivers of distinct adaptation strategies in KN9204 and J411 under low-nitrogen conditions, affecting both root development and the induction of high-affinity nitrate transporters, specifically Nitrate Transporter 2 (NRT2).

Importantly, evidence from histone deacetylase inhibitor treatment and transgenic plants with impaired H3K27me3 methyltransferase function illustrates how modifications in histone profiles can fundamentally influence the preferred adaptation strategies in wheat.

This work, published in the Nature Communications, was funded by the National Key Research and Development Program of China and the National Natural Science Foundation of China.

Epigenetic regulation determination of low-ni trogen adaptation strategy in wheat cultivars (Image by IGDB)