Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China.
Plant Physiol Biochem. 2024 Oct;215:109058. doi: 10.1016/j.plaphy.2024.109058. Epub 2024 Aug 19.
Nitrogen (N) is essential for the physiological processes of plants. However, the specific mechanisms by which different nitrogen forms influence rice blast pathogenesis remain poorly understood. This study used hydroponic assays to explore how ammonium (NH) and nitrate (NO) affect rice after inoculation with Magnaporthe oryzae (M. oryzae). The results showed that NH, compared to NO, significantly reduced disease severity, fungal growth, fungal hyphae number, the expansion capacity of infectious hyphae, and disease-related loss of photosynthesis. Additionally, NH enhanced the expression of defense-related genes, including OsPBZ1, OsCHT1, OsPR1a, and OsPR10. NH-treated rice also exhibited higher hydrogen peroxide (HO) accumulation and increased antioxidant enzyme activities. Moreover, susceptibility to rice blast disease increased when HO was scavenged, while a reduction in susceptibility was observed with the application of exogenous HO. These results suggest that ammonium enhances rice resistance to M. oryzae, potentially through HO accumulation. The findings provide valuable insights into how different nitrogen forms affect plant immunity in rice, which is crucial for controlling rice blast and ensuring stable food production.
氮（N）是植物生理过程所必需的。然而，不同氮形式如何影响稻瘟病发病机制的具体机制仍知之甚少。本研究使用水培试验来探讨铵（NH）和硝酸盐（NO）在接种稻瘟病菌（Magnaporthe oryzae，M. oryzae）后对水稻的影响。结果表明，与 NO 相比，NH 显著降低了病情严重度、真菌生长、真菌菌丝数量、传染性菌丝的扩展能力以及与光合作用相关的损失。此外，NH 增强了防御相关基因的表达，包括 OsPBZ1、OsCHT1、OsPR1a 和 OsPR10。NH 处理的水稻还表现出更高的过氧化氢（HO）积累和增加的抗氧化酶活性。此外，当 HO 被清除时，水稻对稻瘟病的敏感性增加，而外源 HO 的应用则降低了对稻瘟病的敏感性。这些结果表明，铵通过 HO 积累增强了水稻对 M. oryzae 的抗性。这些发现为不同氮形式如何影响水稻植物免疫提供了有价值的见解，这对于控制稻瘟病和确保稳定的粮食生产至关重要。
