Molli-CUTES vs. microbiota: Rewilding maize to resist corn stunt disease

Corn stunt disease, caused by the phloem-limited mollicute Spiroplasma kunkelii and vectored by the leafhopper Dalbulus maidis, is expanding northward in the U.S., due to temperature-driven ecological shifts. While modern maize are susceptible to this disease, wild ancestors are known to be tolerant to pests and pathogens; which is potentially due to the healthier microbiota as shown in our earlier research. To explore this, we developed a reproducible vector-free infection assay with the pathogen inoculum, and controls with media and water. Comprehensive analysis of multiple growth parameters revealed significant differences in plant development. The overall performance metric, the pathogen-infected plants shows significantly reduced performance values expected with corn stunt. These physical changes correlated with distinct spectral Raman spectroscopy patterns. Partial Least Squares Discriminant Analysis (PLS-DA) of Raman spectra from infected vs. control plants showed strong group separation (R² = 0.92, Q² = 0.87), supporting the utility of this method for non-invasive diagnostics. Our current work integrates electropenetrography (EPG), a technique that records the electrical activity of insect stylets during plant tissue penetration. This will help in assessing the insect’s feeding behavior, and its interaction with the pathogen, and thus revealing the mechanisms of disease transmission. This integrative workflow provides a robust platform for future microbiome investigations. This study sets the foundation for sustainable, microbiome-based strategies to manage corn stunt disease by rewilding maize with protective microbes—an urgently needed approach under intensifying climate pressures.