Dissecting the Genetic Basis of Preharvest Sprouting in Rice Using a Genome-Wide Association Study

Area of Science:

• Plant Genetics
• Crop Science
• Molecular Biology

Background:

• Preharvest sprouting (PHS) is a detrimental trait in cereal crops, negatively impacting grain yield and quality.
• The genetic and regulatory mechanisms governing PHS are not fully understood, hindering the development of resistant varieties.

Purpose of the Study:

• To identify genetic loci associated with preharvest sprouting resistance in rice.
• To investigate the role of candidate genes within these loci, particularly novel genes, in regulating PHS.

Main Methods:

• Genome-wide association study (GWAS) using 276 rice accessions from the 3000 Rice Genomes Project.
• Identification and analysis of quantitative trait loci (QTLs) and candidate genes through haplotype and gene expression analysis.

Main Results:

• Seven PHS-associated QTLs were identified, including two novel QTLs. Four QTLs showed stability across multiple years.
• Five candidate genes were identified within stable QTLs. A novel QTL, qPhs-6, contained OsPTF1, a Pi starvation-induced transcription factor 1.
• OsPTF1 was found to play a novel, negative regulatory role in PHS, with two elite haplotypes associated with reduced PHS.

Conclusions:

• The study elucidates the genetic architecture of PHS in rice, identifying key QTLs and candidate genes.
• OsPTF1 is a novel regulator of PHS, offering a potential target for breeding PHS-resistant rice varieties.
• Findings provide a foundation for future research into OsPTF1's function and for developing strategies to mitigate PHS in rice.