Molecular Breeding for Bacterial Blight Resistance in Rice

Bacterial blight, caused by the pathogen Xanthomonas oryzae pv. oryzae, poses a serious threat to global rice production, with potential yield losses of up to 50 per cent under severe epidemics. Conventional control methods rely on chemical treatments and agronomic practices, but durable genetic resistance remains the most sustainable solution. Molecular breeding harnesses advances in genomics and marker technology to identify resistance genes, define their chromosomal locations and assemble multiple genes into high‐performing varieties. Techniques such as quantitative trait locus (QTL) mapping, marker‐assisted selection and gene pyramiding have accelerated the development of rice lines that combine broad‐spectrum resistance, favourable agronomic traits and high grain quality. By deploying both dominant and recessive resistance alleles, and by tapping wild‐species diversity, breeders can outpace the evolving pathogen and reduce reliance on pesticides. The global significance of these efforts is underlined by the rapid adoption of improved cultivars in Asia and beyond, where rice forms the dietary staple for billions.

Research from Nature Portfolio

A recent study has characterised a novel dominant resistance gene, termed Xa46(t), in a japonica mutant line with broad resistance to diverse X. oryzae strains. Through genetic mapping in F2 populations, the locus was refined to a 65 kb interval on chromosome 11. Within this region, expression profiling after bacterial inoculation implicated a serine/threonine-protein kinase gene as the most likely candidate. The work combined high-resolution genotyping with RNA-sequencing to validate differential gene expression and facilitated the development of tightly linked markers for marker-assisted breeding. This research exemplifies the integration of functional genomics and classical genetics to deliver precise tools for the rapid incorporation of new resistance genes into elite rice cultivars.

Molecular Breeding for Bacterial Blight Resistance in Rice publication trend

The graph below shows the total number of articles in molecular breeding for bacterial blight resistance in rice across all publications each year (not limited to Nature Index journals).

Technical terms

Marker-assisted selection: Use of DNA markers linked to target genes to accelerate breeding decisions.

Quantitative trait locus (QTL): A genomic region that contributes to variation in a measurable trait, such as disease resistance.

Gene pyramiding: The process of combining two or more resistance genes into a single cultivar to achieve broad-spectrum or durable resistance.

Near-isogenic line (NIL): A plant line genetically identical to a recurrent parent except for a small introduced segment carrying a target gene.

NB-ARC domain: A conserved nucleotide-binding region found in many plant resistance proteins that mediate pathogen recognition.

Xanthomonas oryzae pv. oryzae (Xoo): The bacterial pathogen responsible for bacterial blight in rice.

References

1. Genetic Enhancement for Biotic Stress Resistance in Basmati Rice through Marker-Assisted Backcross Breeding. International Journal of Molecular Sciences (2023).
2. Fine mapping and sequence analysis reveal a promising candidate gene encoding a novel NB-ARC domain derived from wild rice (Oryza officinalis) that confers bacterial blight resistance. Frontiers in Plant Science (2023).
3. Molecular Breeding for Incorporation of Submergence Tolerance and Durable Bacterial Blight Resistance into the Popular Rice Variety ‘Ranidhan’. Biomolecules (2023).
4. Identification of the novel bacterial blight resistance gene Xa46(t) by mapping and expression analysis of the rice mutant H120. Scientific Reports (2020).