Genetic basis of kernel starch content decoded in a maize multi-parent population

Area of Science:

• Plant Genetics
• Agricultural Science
• Biochemistry

Background:

• Starch is a crucial carbohydrate in maize kernels, vital for nutrition and industrial uses.
• Understanding the genetic basis of starch variation is essential for molecular breeding to enhance maize quality and quantity.

Purpose of the Study:

• To decode the genetic basis of natural variation in maize kernel starch content.
• To identify quantitative trait loci (QTLs) and causal genes influencing starch accumulation.
• To explore the potential of identified genes for improving maize starch and yield.

Main Methods:

• Employed single linkage mapping, joint linkage mapping, and genome-wide association studies (GWAS) in a multi-parent maize population.
• Conducted regional association studies to identify candidate genes underlying QTLs.
• Utilized pathway-driven analysis and gene knockout experiments to validate gene function.

Main Results:

• Identified 50 unique QTLs for starch content, including 18 novel ones, with a few explaining significant phenotypic variation.
• Discovered both additive and epistatic QTLs contributing to starch content variation.
• Pinpointed ZmTPS9, involved in the trehalose pathway, as the causal gene for a major QTL (qSTA4-2); its knockout increased kernel starch and weight.

Conclusions:

• The study elucidates the complex genetic architecture of maize kernel starch content.
• ZmTPS9 is a key gene for starch accumulation and kernel weight, offering a target for maize improvement.
• Findings provide valuable genetic resources for enhancing maize starch quantity and quality.