Facultad de Farmacia, Universidad San Pablo-CEU Universities, Ctra. Boadilla del Monte km 5.3, Boadilla del Monte, 28668, Madrid, Spain.
Sci Rep. 2023 Dec 15;13(1):22507. doi: 10.1038/s41598-023-49533-z.
In addition to genetic adaptative mechanisms, plants retrieve additional help from the surrounding microbiome, especially beneficial bacterial strains (PGPB) that contribute to plant fitness by modulating plant physiology to fine-tune adaptation to environmental changes. The aim of this study was to determine the mechanisms by which the PGPB Bacillus G7 stimulates the adaptive mechanisms of Olea europaea plantlets to high-salinity conditions, exploring changes at the physiological, metabolic and gene expression levels. On the one hand, G7 prevented photosynthetic imbalance under saline stress, increasing the maximum photosynthetic efficiency of photosystem II (Fv/Fm) and energy dissipation (NPQ) and protecting against photooxidative stress. On the other hand, despite the decrease in effective PSII quantum yield (ΦPSII), net carbon fixation was significantly improved, resulting in significant increases in osmolytes and antioxidants, suggesting an improvement in the use of absorbed energy. Water use efficiency (WUE) was significantly improved. Strong genetic reprogramming was evidenced by the transcriptome that revealed involvement of the ABA-mediated pathway based on upregulation of ABA synthesis- and ABA-sensing-related genes together with a strong downregulation of the PLC2 phosphatase family, repressors of ABA-response elements and upregulation of ion homeostasis-related genes. The ion homeostasis response was activated faster in G7-treated plants, as suggested by qPCR data. All these results reveal the multitargeted improvement of plant metabolism under salt stress by Bacillus G7, which allows growth under water limitation conditions, an excellent trait to develop biofertilizers for agriculture under harsh conditions supporting the use of biofertilizers among the new farming practices to meet the increasing demand for food.
除了遗传适应机制外，植物还从周围的微生物群中获取额外的帮助，特别是有益的细菌菌株（PGPB），通过调节植物生理学来微调对环境变化的适应，从而有助于植物的健康。本研究的目的是确定 PGPB 芽孢杆菌 G7 刺激油橄榄植物适应高盐条件的适应机制，探索生理、代谢和基因表达水平的变化。一方面，G7 防止了盐胁迫下的光合作用失衡，增加了光系统 II（Fv/Fm）的最大光合作用效率和能量耗散（NPQ），并保护植物免受光氧化应激。另一方面，尽管有效 PSII 量子产率（ΦPSII）下降，但净碳固定显著提高，导致渗透调节剂和抗氧化剂显著增加，这表明吸收能量的利用得到了改善。水利用效率（WUE）显著提高。转录组证据表明存在强烈的基因重编程，这表明 ABA 介导的途径参与其中，基于 ABA 合成和 ABA 感应相关基因的上调，同时强烈下调 PLC2 磷酸酶家族、ABA 反应元件的抑制剂和上调与离子稳态相关的基因。qPCR 数据表明，G7 处理的植物中更快地激活了离子稳态反应。所有这些结果揭示了芽孢杆菌 G7 在盐胁迫下对植物代谢的多靶点改善，这使得植物在水分限制条件下也能生长，这是在恶劣条件下开发农业生物肥料的一个极好特性，有助于在新的农业实践中使用生物肥料来满足不断增长的粮食需求。
