Table 3_Inoculation frequency and maize genotype influence plant growth-promoting effects of soil bacteria under low nitrogen conditions.xlsx

Global agriculture relies heavily on the use of synthetic nitrogen fertilizer to meet the current global food demand. Unfortunately, the average nitrogen-use efficiency (NUE) of maize (Zea mays ssp. mays) is as low as 50%. Improving the NUE of maize is essential for feeding the ever-increasing world population while also decreasing the negative environmental impacts of nitrogen fertilizer due to runoff and volatilization. Harnessing the symbiotic relationship between plants and soil microorganisms may be one method for increasing the NUE in crops such as maize. In the present study, a set of potentially beneficial bacterial species chosen based on genetic information from the host was investigated for their ability to improve NUE-related traits in maize grown under nitrogen-deficient conditions. This was carried out through non-repeated and repeated bacterial inoculations using different maize genotypes. We identified several growth-promoting bacterial isolates and observed a significant interaction between the bacterial isolates and the maize genotype, suggesting a strong interaction between the host genetics and the effects of bacterial isolates. In addition, our results showed a significant growth response to repeated inoculations with a beneficial bacterial isolate. In summary, when evaluating the plant-growth-promoting effects of a bacterial species, it is essential to consider the interaction between host plant genotype and bacterial isolate. In addition, when inoculating with bacterial isolates, multiple inoculations appear to be more effective than a single inoculation after bacterial seed priming.

全球农业高度依赖合成氮肥以满足当前全球粮食需求。遗憾的是，玉米（Zea mays ssp. mays）的平均氮素利用效率（nitrogen-use efficiency, NUE）仅约50%。提升玉米的氮素利用效率，既是保障全球持续增长人口粮食供给的核心需求，也可降低氮肥因径流与挥发所引发的负面环境影响。
挖掘植物与土壤微生物的共生关系，或许是提升玉米等作物氮素利用效率的可行路径之一。本研究针对一组基于宿主遗传信息筛选获得的潜在有益细菌菌株，探究其在缺氮培养条件下对玉米氮素利用效率相关性状的改良效果。实验采用不同玉米基因型，分别开展单次与重复细菌接种处理。
研究团队筛选得到多株促生长细菌分离株，并观察到细菌分离株与玉米基因型间存在显著交互作用，这表明宿主遗传学与细菌分离株的作用之间存在紧密关联。此外，本研究结果显示，对有益细菌分离株进行重复接种，可显著促进植物生长。
综上，在评估细菌菌株的促植物生长效应时，必须考虑宿主植物基因型与细菌分离株之间的交互作用。同时，在完成细菌种子引发后进行接种时，多次接种相较于单次接种似乎能取得更优的效果。