Abstract Rice sheath blight causes serious damage to rice crops in China. The most common practice for rice sheath blight control is still chemical treatment, an environmentally unfriendly way. Studies have demonstrated the use of nitrogen-fixing cyanobacteria to prevent crop diseases as well as to improve soil fertility and crop productivity. However, little information is available on the biocontrol of rice sheath blight using cyanobacteria. Therefore, the objective of the present study was to screen and evaluate the biocontrol effect of nitrogen-fixing cyanobacteria against the disease through microchamber and microarea experiments. Based on the results of the microchamber experiment, three strains (SCAU04, SCAU15, and SCAU26) out of nine nitrogen-fixing cyanobacterial strains with a significant inhibition (>80%) on rice sheath blight were selected. Further, microarea experiments during two seasons demonstrated the highest disease control efficacy (54.5%) on day 20 with SCAU26 treatment. Moreover, the algal treatments significantly promoted root length, underground biomass, and number of grains per panicle. SCAU04 and SCAU26 treatments significantly improved the rice theoretical yield and significantly (P

中文翻译：

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杂囊固氮蓝藻对水稻纹枯病的影响及机制

摘要 水稻纹枯病对我国水稻作物造成严重危害。水稻纹枯病控制最常见的做法仍然是化学处理，这是一种对环境不友好的方式。研究表明，使用固氮蓝藻可以预防作物病害以及提高土壤肥力和作物生产力。然而，关于使用蓝藻生物防治水稻纹枯病的信息很少。因此，本研究的目的是通过微室和微区实验筛选和评价固氮蓝藻对该病害的生防效果。根据微室实验结果，9 株固氮蓝藻菌株中的 3 株（SCAU04、SCAU15 和 SCAU26）具有显着抑制（> 80%) 的水稻纹枯病被选中。此外，两个季节的微区实验表明，SCAU26 治疗在第 20 天的疾病控制效果最高（54.5%）。此外，藻类处理显着提高了根长、地下生物量和每穗粒数。SCAU04和SCAU26处理显着提高水稻理论产量，显着（P