Abstract：
Symbiotic nitrogen fixation can reduce the impact of agriculture on the environment by reducing fertilizer input. The rapid development of nanomaterials in agriculture provides a new prospect for us to improve the biological nitrogen fixation ability of leguminous crops. Molybdenum is an important component of nitrogenase, and the potential application of MoO3NPs in agriculture is largely unexplored. In this study, on the basis of verifying that MoO3NPs can improve the nitrogen fixation ability of soybean, the effects of MoO3NPs on the symbiotic nitrogen fixation process of soybean were investigated by using dynamic transcriptome and targeted metabolome techniques. Here we showed that compared with conventional molybdenum fertilizer, minute concentrations of MoO3NPs (0.01-0.1 mg kg-1) could promote soybean growth and nitrogen fixation efficiency. The nodules number, fresh nodule weight and nitrogenase activity of 0.1 mg kg-1 were increased by 17 %, 14 % and 27 %, and plant nitrogen accumulation increased by 17 %. Compared with conventional molybdenum fertilizer, MoO3NPs had a greater effect on apigenin, kaempferol and other flavonoid, and the expression of nodulation related genes such as ENOD93, F3\'H. Based on WGCNA analysis, we identified a core gene GmCHS9 that was positively responsive to molybdenum and was highly expressed during MoO3NPs induced nodulation. MoO3NPs could improve the nitrogen fixation ability of soybean by promoting the secretion of flavonoids and the expression of key genes. This study provided a new perspective for the nano-strengthening strategy of nodules development and flavonoid biosynthesis by molybdenum.
摘要：
共生固氮可以通过减少化肥投入来减少农业对环境的影响。纳米材料在农业中的快速发展为我们提高豆科作物的生物固氮能力提供了新的前景。钼是固氮酶的重要成分，MoO3NP在农业中的潜在应用在很大程度上尚未开发。在这项研究中,在验证MoO3NPs能够提高大豆固氮能力的基础上,利用动态转录组和靶向代谢组技术研究了MoO3NPs对大豆共生固氮过程的影响。在这里我们表明，与常规钼肥相比，微量浓度的MoO3NPs（0.01-0.1mgkg-1）可以促进大豆的生长和固氮效率。结节数量,0.1mgkg-1的新鲜结节重量和固氮酶活性增加了17％，14%和27%，植株氮素积累量增加17%。与常规钼肥相比，MoO3NP对芹菜素的影响更大，山奈酚和其他类黄酮，和结瘤相关基因如ENOD93，F3\'H的表达。基于WGCNA分析，我们确定了一个核心基因GmCHS9，该基因对钼呈正反应，并且在MoO3NP诱导的结瘤过程中高度表达。MoO3NPs可以通过促进黄酮类化合物的分泌和关键基因的表达来提高大豆的固氮能力。该研究为根瘤发育和钼生物合成类黄酮的纳米强化策略提供了新的视角。
