QTL mapping and transcriptome analysis identify candidate genes regulating pericarp thickness in sweet corn.

Area of Science:

• Plant Genetics
• Crop Breeding
• Molecular Biology

Background:

• Sweet corn cultivation is expanding in China, with new high-yield varieties.
• Improving edible quality, specifically reducing pericarp thickness, remains a challenge.
• Pericarp thickness is a key determinant of sweet corn's edible quality.

Purpose of the Study:

• To identify novel quantitative trait loci (QTLs) for pericarp thickness in sweet corn.
• To pinpoint candidate genes associated with pericarp thickness variation.
• To facilitate the development of sweet corn varieties with thinner pericarps.

Main Methods:

• Developed a BC4F3 population from two distinct sweet corn lines.
• Constructed a high-density genetic linkage map using specific length amplified fragment (SLAF) tags.
• Performed quantitative trait loci (QTL) mapping and transcriptome analysis.

Main Results:

• Identified 14 QTLs for pericarp thickness, including one stable QTL (qPT10-5) on chromosome 10.
• Located 42 candidate genes within the qPT10-5 region.
• Found five differentially expressed genes, with three (GRMZM2G143352, GRMZM2G143402, GRMZM2G143389) identified as potential candidates for controlling pericarp thickness.

Conclusions:

• A major QTL and candidate genes for sweet corn pericarp thickness were identified.
• These findings can accelerate breeding programs for thin-pericarp sweet corn varieties.
• Provides a foundation for map-based cloning and further functional studies.