Transcriptome analysis reveals the mechanism of internode development affecting maize stalk strength

Area of Science:

• Plant Biology
• Agricultural Science
• Genetics

Background:

• Maize stalk strength is crucial for preventing lodging, with the stalk rind being a key contributing factor.
• The developmental mechanisms of maize stalk rind remain largely uncharacterized.

Purpose of the Study:

• To investigate the mechanical, anatomical, and biochemical differences between stiff-stalk (SS) and non-stiff-stalk (NSS) maize lines.
• To identify molecular mechanisms underlying enhanced stalk strength in maize.

Main Methods:

• Comparative analysis of mechanical (penetrometer resistance), anatomical (rind thickness), and biochemical (dry matter, cellulose, hemicellulose, lignin) properties.
• RNA sequencing (RNA-seq) to compare transcriptomes of the third basal internode between SS and NSS lines at key developmental stages (ninth leaf and tasseling).
• Gene Ontology (GO) enrichment analysis to identify significantly regulated biological pathways.

Main Results:

• Stiff-stalk (SS) lines exhibited significantly higher rind penetrometer resistance, increased rind thickness, and greater dry matter, hemicellulose, cellulose, and lignin content per unit length compared to the non-stiff-stalk (NSS) line.
• Gene Ontology analysis revealed significant upregulation of genes involved in hydrolase activity and cytoskeleton organization in SS lines at the ninth leaf stage.
• Genes related to microtubule processes and cell wall metabolism were significantly upregulated in SS lines at the tasseling stage.

Conclusions:

• Cell wall polysaccharide synthesis and cytoskeleton dynamics are critical for maize internode development and stalk strength.
• The findings provide a basis for selecting lodging-resistant inbred lines and breeding improved maize cultivars.