Boosting Rice Disease Resistance with CRISPR Gene Editing

Greg Howard
21st March, 2024

Boosting Rice Disease Resistance with CRISPR Gene Editing

Image Source: Natural Science News, 2024

Key Findings

  • Most japonica rice in China's Jilin Province lacks a gene variant (Bsr-d1) that resists rice blast disease
  • Scientists used CRISPR to edit the rice, creating mutants with stronger resistance to the disease
  • The edited rice produced more hydrogen peroxide, a defense against the rice blast fungus
Rice blast disease, caused by the fungus Magnaporthe oryzae, is a major threat to rice production worldwide. It leads to significant yield losses and poses challenges to food security. The disease is notorious for its ability to overcome resistance in rice varieties, making it difficult to manage. In the fight against this relentless pathogen, scientists from the Jilin Academy of Agricultural Sciences have made a breakthrough[1]. They discovered that a particular allele (variant of a gene) known as Bsr-d1, which confers resistance to rice blast, is absent in most japonica rice varieties from Jilin Province, China. This finding is crucial because japonica rice is widely cultivated in the region. Building on previous research that identified Bsr-d1 in the indica rice cultivar Digu as a broad-spectrum resistance gene[2], the team set out to understand its role in japonica varieties. They analyzed 256 japonica rice varieties and found the resistance allele missing, indicating a vulnerability to blast disease in these crops. To address this, they employed CRISPR/Cas9, a cutting-edge gene-editing technology, to knock out the Bsr-d1 gene in a japonica rice variety. The resulting Bsr-d1 knockout mutants showed enhanced resistance to multiple strains of the rice blast fungus. This study ties into earlier findings that the Bsr-d1 gene regulates the redox state of plant cells and affects various metabolic processes, including the metabolism of amino acids and unsaturated fatty acids[2]. The Bsr-d1 gene also plays a role in the immune response by regulating the levels of hydrogen peroxide, a molecule involved in plant defense mechanisms. The new research confirms that Bsr-d1 knockout mutants produce more hydrogen peroxide when attacked by the fungus, which likely contributes to their increased resistance. Moreover, the study's comparative RNA sequencing analysis revealed that the knockout mutants exhibited differences in gene expression related to amide compounds, zinc finger proteins, and transmembrane transporters, among other things. These findings suggest that Bsr-d1 has a broad impact on the plant's response to infection. The research builds on a body of work seeking to understand how miRNAs, small RNA molecules that regulate gene expression, contribute to rice's resistance to blast disease[3]. It also leverages knowledge about other genetic factors that confer broad-spectrum resistance without compromising crop yield[4]. For instance, the discovery of a natural allele of a transcription factor that enhances resistance by reducing the expression of Bsr-d1 through the binding of a repressive MYB transcription factor[5] adds to the genetic toolkit available for rice breeding. The Jilin Academy of Agricultural Sciences' study not only advances our understanding of the Bsr-d1 gene's role in rice blast resistance but also provides practical solutions for breeding more resilient rice varieties. By developing Bsr-d1 knockout mutants that are resistant to a wide range of M. oryzae strains, the researchers have equipped breeders with new germplasm resources. These resources can be used to cultivate rice varieties that maintain high yields while withstanding the pervasive threat of rice blast, thereby securing the staple food for millions of people. In summary, the study demonstrates the power of gene editing to improve crop resistance to diseases and the potential of targeted genetic interventions to enhance food security. The findings represent a significant step forward in the ongoing battle against rice blast disease and offer hope for more sustainable agricultural practices in the future.

AgricultureBiotechGenetics

References

Main Study

1) CRISPR/Cas9-mediated knockout of Bsr-d1 enhances the blast resistance of rice in Northeast China.

Published 18th March, 2024

https://doi.org/10.1007/s00299-024-03192-0

Related Studies

2) New insights into bsr-d1-mediated broad-spectrum resistance to rice blast.

https://doi.org/10.1111/mpp.12941

3) Unraveling the transcriptional network regulated by miRNAs in blast-resistant and blast-susceptible rice genotypes during Magnaporthe oryzae interaction.

https://doi.org/10.1016/j.gene.2023.147718

4) Recent advances in broad-spectrum resistance to the rice blast disease.

https://doi.org/10.1016/j.pbi.2019.03.015

5) A Natural Allele of a Transcription Factor in Rice Confers Broad-Spectrum Blast Resistance.

https://doi.org/10.1016/j.cell.2017.06.008


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