Carbon dots as a green alternative for preventing Magnaporthe oryzae infection in rice: Mechanisms of disease resistance

The current study investigates the potential of carbon dots (CDs) as an eco-friendly "plant vaccine" for controlling rice blast disease caused by <i>Magnaporthe oryzae.</i> These CDs offer a promising alternative to commercial fungicides that threaten environmental and human health. Foliar application of CDs (at 100 and 200 ​mg/L) at the tillering stage enhanced rice blast resistance across the entire life cycle. CDs significantly reduced the leaf blast disease index, with infection rates of 30.8%-49.5%, outperforming the commercial fungicide isoprothiolane (57.3%). CDs significantly increased grain yield (186%-198%), starch content in grains (27.0%-27.5%), and protein content in grains (25.4%-36.1%) relative to infected controls. Moreover, CDs demonstrated lower toxicity to soil organisms (<i>Eisenia fetida</i> and <i>Caenorhabditis elegans</i>) than isoprothiolane. Mechanistically, CDs stabilized chloroplast homeostasis, amplified photosynthesis, and enhanced carbohydrate allocation, thereby synchronously activating systemic resistance through indole acetic and jasmonic acid signaling. These dual agricultural and environmental benefits position CDs as a sustainable crop protection strategy, reconciling food security with ecological safety.