Engineering broad-spectrum disease-resistant rice by editing multiple susceptibility genes

Area of Science:

• Plant Pathology
• Genetics
• Agricultural Science

Background:

• Rice blast (Magnaporthe oryzae) and bacterial blight (Xanthomonas oryzae pv. oryzae) are major threats to rice (Oryza sativa) production worldwide.
• Developing broad-spectrum resistant rice varieties is crucial for sustainable agriculture.
• Targeting susceptibility (S) genes offers a novel approach to disease resistance, distinct from traditional resistance gene strategies.

Purpose of the Study:

• To investigate the potential of editing rice S genes for enhanced resistance to rice blast and bacterial blight.
• To assess the efficacy of CRISPR/Cas9 technology in generating loss-of-function mutants of specific S genes (Pi21, Bsr-d1, Xa5).
• To evaluate the agronomic performance of edited rice lines.

Main Methods:

• Utilized CRISPR/Cas9 gene editing to create loss-of-function mutants of rice S genes Pi21, Bsr-d1, and Xa5.
• Assessed the resistance of generated mutants against Magnaporthe oryzae and Xanthomonas oryzae pv. oryzae.
• Compared the agronomic traits of triple S gene mutants with wild-type rice.

Main Results:

• Loss-of-function mutants of Pi21 and Bsr-d1 exhibited increased resistance to Magnaporthe oryzae.
• A knockout mutant of Xa5 showed enhanced resistance to Xanthomonas oryzae pv. oryzae.
• A triple mutant simultaneously edited for Pi21, Bsr-d1, and Xa5 demonstrated significantly improved resistance to both pathogens.
• The triple mutant maintained agronomic performance comparable to wild-type rice.

Conclusions:

• Simultaneous editing of multiple S genes is a potent strategy for developing rice with broad-spectrum resistance to major diseases.
• This approach offers a promising avenue for breeding resilient rice varieties.
• CRISPR/Cas9 technology is effective for generating multi-gene edited rice with desirable disease resistance and agronomic traits.