{
  "abstract": "Perennial ryegrass (Lolium perenne) is the most widely sown forage grass of temperate agriculture and a major sink for fertiliser nitrogen, yet the cellular basis of its nitrogen-use efficiency (NUE) is unknown. We built a single-nucleus atlas of 76,684 root nuclei from a high- and a low-NUE genotype under matched nitrogen resupply. High-affinity nitrate uptake is concentrated in one cortical cell state that co-expresses nine NRT2 transporters and all three NAR2 partner proteins, a state that whole-root RNA-seq of the same tissue cannot resolve. Under reduced nitrogen the low-NUE genotype induces this state, whereas the high-NUE genotype does not; it expresses NRT2.3 at a higher baseline and uses different NRT2 paralogs, with one array member nearly silent. Across 44 annual and perennial Pooideae genomes, the same gene families show no life-history difference in copy number, evolutionary rate or selection intensity. Their regulation, however, varies in the same direction as between the two genotypes: the perennial Brachypodium sylvaticum expresses the NRT2.3 ortholog at the level that the annual B. distachyon reaches only under nitrogen deprivation, and an N-efficient barley genotype does not induce the transporters that an N-sensitive genotype induces. NUE differences are therefore associated with constitutive versus inducible deployment of a conserved toolkit, and the expression and presence/absence variants we identify are candidate breeding markers. The atlas, the first for a forage grass, is released as an open web resource.",
  "abstract_shown": true,
  "affiliations": [
    "Norwegian University of Life Sciences, Norway"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 18,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "M. R. Kovi"
    },
    {
      "name": "P. Guevarra"
    },
    {
      "name": "S. Thu"
    },
    {
      "name": "E. T. M. Kragholm"
    },
    {
      "name": "A. R. Pashapu"
    },
    {
      "name": "F. H. Nohr"
    },
    {
      "name": "I. F. da Costa"
    },
    {
      "name": "M. Steinkopf"
    },
    {
      "name": "K. H. Gylstrom"
    },
    {
      "name": "H. Amdahl"
    },
    {
      "name": "P. Manishankar"
    },
    {
      "name": "J. M. Alcantara"
    },
    {
      "name": "S. Windju"
    },
    {
      "name": "M. Veerabagu"
    },
    {
      "name": "M. Alsheikh"
    },
    {
      "name": "S. Fjellheim"
    },
    {
      "name": "R. S. Sobral"
    },
    {
      "name": "O. A. Rognli"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6jxbstjtegmfq.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.12.758384",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758384v1.full",
  "id": "6jxbstjtegmfq",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758384v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "plant biology"
    ],
    [
      "openalex",
      "1110|Plant nutrient uptake and metabolism"
    ]
  ],
  "openalex": "W7221747132",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758384v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6jxbstjtegmfq.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:47Z",
      "native_id": "10.64898/2026.10.12.758384",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758384v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:plant biology",
      "subfield": "plant-biology"
    }
  ],
  "title": "A constitutively active cortical nitrate-uptake cell state underlies nitrogen-use efficiency in perennial ryegrass",
  "title_text": "A constitutively active cortical nitrate-uptake cell state underlies nitrogen-use efficiency in perennial ryegrass",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:47Z",
  "url": "https://research.draconitic.com/paper/6jxbstjtegmfq",
  "venue": "bioRxiv",
  "versions": []
}