Genomic and Transcriptomic Analyses Reveal Pathways and Genes Associated With Brittle Stalk Phenotype in Maize

Area of Science:

• Plant genetics
• Molecular biology
• Agricultural science

Background:

• Maize stalk mechanical strength is crucial for lodging resistance and digestibility.
• The molecular basis for brittle stalk phenotypes in maize is not well understood.

Purpose of the Study:

• To investigate the genetic and molecular mechanisms underlying the brittle stalk phenotype in maize.
• To identify candidate genes and pathways involved in regulating maize stalk integrity.

Main Methods:

• Generated a brittle stalk mutant (bk5) in maize via crossing.
• Performed RNA-sequencing (RNA-seq) for gene expression analysis.
• Utilized bulked-segregant sequence analysis (BSA-seq) to identify causative mutations.

Main Results:

• The bk5 mutant exhibited a brittle stalk phenotype across all plant organs after the five-leaf stage.
• Significant differences in cell wall composition (cellulose, lignin, starch, soluble sugar) were observed between mutant and wild-type stalks.
• RNA-seq identified 226 differentially expressed genes, with pathways related to endocytosis and GPI-anchored biosynthesis implicated.
• BSA-seq pinpointed 17 candidate genes with mutations, some linked to cellulose and lignin synthesis, with overlapping differential expression from RNA-seq.

Conclusions:

• The study elucidates key molecular mechanisms contributing to brittle stalks in maize.
• Identified candidate genes provide targets for future research on improving maize stalk strength and crop yield.