Transcriptomic Analysis Reveals Candidate Genes Responding Maize Gray Leaf Spot Caused by Cercospora zeina

Area of Science:

• Plant Pathology
• Molecular Biology
• Genetics

Background:

• Gray leaf spot (GLS), caused by *Cercospora zeina*, is a major destructive soil-borne disease impacting maize (*Zea mays* L.) production, particularly in Southwest China.
• The precise mechanisms underlying maize resistance to GLS remain largely unclear, with limited identification of resistant alleles.
• Understanding these resistance mechanisms is crucial for developing effective disease management strategies and improving crop yields.

Purpose of the Study:

• To elucidate the molecular mechanisms of maize resistance to gray leaf spot (GLS).
• To identify key genes and pathways involved in the plant's response to *Cercospora zeina* infection.
• To provide genetic resources for enhancing GLS resistance in maize breeding programs.

Main Methods:

• Comparative transcriptome analysis of resistant (R6) and susceptible (S8) maize inbred lines inoculated with *Cercospora zeina* spore suspensions.
• Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of differentially expressed genes (DEGs).
• Weighted-Genes Co-expression Network Analysis (WGCNA) and integration with Quantitative Trait Loci (QTL) mapping to identify candidate resistance genes.

Main Results:

• A total of 667 and 419 stable common DEGs were identified in resistant and susceptible lines, respectively, across multiple time points post-inoculation.
• Enrichment analysis revealed significant involvement of 'response to stimulus,' 'response to stress,' 'plant-pathogen interaction,' 'MAPK signaling pathways,' and 'plant hormone signal transduction.'
• WGCNA identified hub genes related to plant hormone and calcium signaling, and transcription factors. Five consensus genes, including two putative Leucine-rich repeat protein kinase family proteins specifically expressed in the resistant line, were identified.

Conclusions:

• Plant hormone signaling, calcium signaling pathways, and transcription factors play critical roles in maize's perception and response to GLS.
• The identified consensus genes, particularly the Leucine-rich repeat protein kinase family proteins, represent promising targets for genetic improvement of GLS resistance in maize.
• This study provides valuable molecular resources for further research into the mechanisms of GLS resistance and for developing durable resistance strategies in maize.