Transcriptomic Analysis of a Susceptible African Maize Line to Fusarium verticillioides Infection

Area of Science:

• Plant Pathology
• Molecular Biology
• Genomics

Background:

• Maize (Zea mays L.) is crucial for food security in sub-Saharan Africa.
• Fusarium verticillioides causes Fusarium Ear Rot, reducing maize yield and quality.
• No African maize line exhibits complete resistance to F. verticillioides.

Purpose of the Study:

• Investigate the molecular response of the African maize line CML144 to F. verticillioides infection.
• Identify differentially expressed genes (DEGs) and defense mechanisms.
• Provide insights into maize resistance against Fusarium Ear Rot.

Main Methods:

• Morphological analysis of infected and mock-inoculated plants.
• RNA-sequencing (RNA-seq) to identify DEGs at 14 days post-inoculation.
• Kauralexin analysis, Gene Ontology (GO) enrichment, and quantitative real-time PCR (qRT-PCR).

Main Results:

• Significant morphological differences observed between infected and control plants.
• Identified up-regulated maize TPS1 and cytochrome P450 genes, suggesting kauralexin involvement.
• Kauralexins (class A and B) accumulated in infected tissues; GO terms related to stimulus response and carbohydrate metabolism were enriched and genes down-regulated.
• qRT-PCR and phytoalexin analysis validated RNA-seq and GO findings.
• 18 DEGs, including 17 up-regulated and 1 down-regulated, were common with a previous study on different maize genotypes.

Conclusions:

• The African maize line CML144 mounts a defense response against F. verticillioides involving kauralexin accumulation.
• This study is the first transcriptomic analysis of CML144 in response to F. verticillioides.
• Findings contribute to understanding maize resistance mechanisms and breeding efforts for Fusarium Ear Rot.