Silicon modulation of sugarcane seedling growth and disease resistance against Nigrospora oryzae: a transcriptomic and metabolomic approach.

Main conclusion: Silicon application at a concentration of 2 mM induced sugarcane resistance to Nigrospora oryzae by upregulating pathogen recognition and defense genes, thus increasing plant metabolic activities and productivity. Sugarcane is an important global food and industrial crop, but numerous pathogens threaten its productivity. Our team recently identified the fungus Nigrospora oryzae as a pathogen affecting sugarcane's growth and productivity. Although silicon supplementation is active against most fungi, it remains unclear if it would enhance the resilience of sugarcane to N. oryzae, and molecular mechanisms underlying this process are yet to be explored. In this study, we explored the effects of four silicon concentrations (control, 1 mM, 2 mM, and 4 mM) on the growth and disease resistance of seedlings of the sugarcane variety ROC22 under fungal stress. Employing an integrative approach combining detailed phenotypic analysis with transcriptomic and metabolomic profiling, we elucidated the underlying molecular mechanisms of silicon's protective effects. Results indicated that optimal concentrations (2 mM) of silicon enhanced disease resistance and significantly improved plant height, root characteristics, and enzymatic activities. Transcriptomic analysis revealed an upregulation of genes (826) involved in pathogen recognition and defensive response, while metabolomic analysis highlighted alterations in metabolic pathways pertinent to stress response. These findings suggest that silicon supplementation could effectively bolster sugarcane's defense against fungal diseases, offering new insights into its role in plant pathology and paving the way for developing more resilient crop varieties.