The First Genome-Wide Mildew Locus O Genes Characterization in the Lamiaceae Plant Family

Area of Science:

• Plant Pathology
• Genomics
• Molecular Biology

Background:

• Powdery mildew (PM) causes significant crop losses, particularly in Lamiaceae species.
• mlo-resistance, a form of PM resistance, is linked to the inactivation of specific Mildew Locus O (MLO) genes.

Purpose of the Study:

• To perform a genome-wide characterization of the MLO gene family in 11 Lamiaceae species.
• To identify potential MLO genes for use in crop breeding programs aimed at enhancing PM resistance.

Main Methods:

• Genome-wide characterization of MLO gene family in 11 Lamiaceae species.
• Phylogenetic analysis using maximum likelihood and motif pattern reconstruction.
• Codon-based evolutionary analysis to assess selection pressures.

Main Results:

• A catalog of 324 MLO proteins was curated across the 11 Lamiaceae species.
• Seven distinct MLO clades were identified, originating from an ancestral domain pattern with 18 conserved motifs.
• 74 putative PM susceptibility genes were located within clade V, with evidence of purifying selection and some diversifying selection in candidate genes.

Conclusions:

• The genomic characterization of Lamiaceae MLO genes provides a foundation for understanding PM susceptibility.
• Identification of candidate susceptibility genes offers targets for future research into PM resistance strategies, such as gene silencing or loss-of-function mutations.