Rice Science

Rice Science

• Research Paper • Previous Articles     Next Articles

Knockout of OsHIPP19 Reduces Rice Susceptibility to Root-Knot Nematode Meloidogyne graminicola

  1. Division of Nematology, Indian Council of Agricultural Research (ICAR)-Indian Agricultural Research Institute, New Delhi 110012, India; Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India; Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India; Department of Nematology, University of California, Riverside, CA 92521, USA; Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA; Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
  • Contact: Tushar K. DUTTA; Simon C. GROEN
  • Supported by:
    Simon C. Groen thanks the University of California Riverside for providing funding for this work. Tushar K. Dutta acknowledges Indian Council of Agricultural Research (ICAR) Expenditure Finance Committee project ‘Enhancing climate resilience and ensuring food security with genome editing tools’ (Grant No. 12-197-K) for supporting the current study. We thank In-Charge, Phytotron facility, ICAR-Indian Agricultural Research Institute for providing us space to grow transgenic rice plants.

PDF

Supplement

1

Abstract: Direct-seeded rice (DSR) offers a sustainable alternative for climate-resilient agriculture, but it is severely threatened by the root-knot nematode Meloidogyne graminicola. Knockout of susceptibility (S) genes has emerged as a promising strategy to combat such obligate parasites. Among candidate S genes, heavy metal-associated (HMA) domain containing isoprenylated plant proteins (HIPPs) are central regulators of plant stress responses. Here, we show that CRISPR/Cas9-mediated knockout of the nematode-responsive S gene, OsHIPP19, reduces susceptibility to M. graminicola in the DSR cultivar Pusa 2090. Given the variable transformation efficiency among Oryza sativa ssp. indica rice cultivars, we first standardized an immature embryo-derived callus culture method for Pusa 2090. Subsequently, we generated three loss-of-function mutant lines harboring novel alleles. In microplot trials, these lines exhibited a 38.75%‒40.08% reduction in gall counts and a 40.26%‒42.66% reduction in nematode multiplication compared with control plants. Conversely, OsHIPP19 overexpression exhibited hypersusceptibility to M. graminicola, and reintroducing OsHIPP19 into a resistant knockout line restored susceptibility. The role of OsHIPP19 as an S gene was further confirmed by promoter-GUS reporter assays and expression analysis of defense-related marker genes. Notably, OsHIPP19 knockout did not cause yield penalties in Pusa 2090, highlighting the translational potential of this approach for engineering sustainable nematode resistance in crops.

Key words: CRISPR/Cas9 technology, heavy metal-associated domain containing isoprenylated plant proteins, rice transformation, direct-seeded rice agriculture, nematode susceptibility, defense response