A new genome allows the identification of genes associated with natural variation in aluminium tolerance in Brachiaria grasses

Authors Organisations
  • Margaret Worthington(Author)
    Centro Internacional de Agricultura Tropical (CIAT)
  • Juan Perez(Author)
    Centro Internacional de Agricultura Tropical (CIAT)
  • Saule Mussurova(Author)
    The Earlham Institute
  • Alexander Silva-Cordoba(Author)
    Centro Internacional de Agricultura Tropical (CIAT)
  • Valheria Castiblanco(Author)
    Centro Internacional de Agricultura Tropical (CIAT)
  • Juan Arango(Author)
    Centro Internacional de Agricultura Tropical (CIAT)
  • Charlotte Jones(Author)
  • Narcis Fernandez Fuentes(Author)
  • Leif Skot(Author)
  • Sarah Dyer(Author)
    The Earlham Institute
  • Joe Tohme(Author)
    Centro Internacional de Agricultura Tropical (CIAT)
  • Federica Di Palma(Author)
    The Earlham Institute
  • Jacobo Arango(Author)
    Centro Internacional de Agricultura Tropical (CIAT)
  • Ian Armstead(Author)
  • Jose De Vega(Author)
    The Earlham Institute
Type Article
Original languageEnglish
Pages (from-to)302-319
Number of pages18
JournalJournal of Experimental Botany
Volume72
Issue number2
Early online date16 Oct 2020
DOI
Publication statusPublished - 02 Feb 2021
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Abstract

Toxic concentrations of aluminium cations and low phosphorus availability are the main yield-limiting factors in acidic soils, which represent half of the potentially available arable land. Brachiaria grasses, which are commonly sown as forage in the tropics because of their resilience and low demand for nutrients, show greater tolerance to high concentrations of aluminium cations (Al3+) than most other grass crops. In this work, we explored the natural variation in tolerance to Al3+ between high and low tolerant Brachiaria species and characterized their transcriptional differences during stress. We identified three QTLs (quantitative trait loci) associated with root vigour during Al3+ stress in their hybrid progeny. By integrating these results with a new Brachiaria reference genome, we identified 30 genes putatively responsible for Al3+ tolerance in Brachiaria. We observed differential expression during stress of genes involved in RNA translation, response signalling, cell wall composition, and vesicle location homologous to aluminium-induced proteins involved in limiting uptake or localizing the toxin. However, there was limited regulation of malate transporters in Brachiaria, which suggests that exudation of organic acids and other external tolerance mechanisms, common in other grasses, might not be relevant in Brachiaria. The contrasting regulation of RNA translation and response signalling suggests that response timing is critical in high Al3+-tolerant Brachiaria.

Keywords

  • Acid soils, Brachiaria, QTL mapping, Urochloa, aluminium tolerance, differential expression, genome assembly, grass

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