Xu Fangfang, Liang Yungang, Wang Xiaobing, Guo Yuze, Tang Kai, Feng Fuying
Laboratory for Environmental Microbiology and Biotechnology in Arid and Cold Regions, College of Life Sciences, Inner Mongolia Agricultural University, Hohhot, China.
Laboratory for Wheat Breeding and Cultivation, Institute of Crop Sciences, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China.
Front Microbiol. 2023 Jan 16;13:1100232. doi: 10.3389/fmicb.2022.1100232. eCollection 2022.
Although microorganisms and silicon are well documented as factors that mitigate salt stress, their effect mitigating saline-alkaline stress in plants remains unknown. In this study, wheat plant seeds were treated with silicon, sp. FN0603 alone and in combination of both. Wheat seeds were soaked in silicon and bacterial solutions and sown in pots containing artificial saline-alkaline soils to compare the effects among all treatments. The results showed that the treatments with silicon and FN0603 alone significantly changed plant morphology, enhanced the rhizosphere soil nutrient content and enzyme activities, improved some important antioxidant enzyme activities (e.g., superoxide dismutase) and the contents of small molecules (e.g., proline) that affected osmotic conditions in the top second leaves. However, treatment with silicon and FN0603 in combination significantly further increased these stress tolerance indexes and eventually promoted the plant growth dramatically compared to the treatments with silicon or FN0603 alone ( < 0.01), indicating a synergic plant growth-promoting effect. High relative abundance of strain FN0603 was detected in the treated plants roots, and silicon further improved the colonization of FN0603 in stressed wheat roots. Strain FN0603 particularly when present in combination with silicon changed the root endophytic bacterial and fungal communities rather than the rhizosphere communities. Bipartite network analysis, variation partitioning analysis and structure equation model further showed that strain FN0603 indirectly shaped root endophytic bacterial and fungal communities and improved plant physiology, rhizosphere soil properties and plant growth through significantly and positively directing FN0603-specific biomarkers ( < 0.05). This synergetic effect of silicon and plant growth-promoting microorganism in the mitigation of saline-alkaline stress in plants shaping root endophyte community may provide a promising approach for sustainable agriculture in saline-alkaline soils.
虽然微生物和硅作为缓解盐胁迫的因素已有充分记载，但它们缓解植物盐碱胁迫的作用仍不清楚。在本研究中，小麦植株种子分别用硅、菌株FN0603单独处理以及两者组合处理。将小麦种子浸泡在硅溶液和细菌溶液中，然后播种在装有人工盐碱土的花盆中，以比较所有处理之间的效果。结果表明，单独用硅和FN0603处理显著改变了植株形态，提高了根际土壤养分含量和酶活性，改善了一些重要的抗氧化酶活性（如超氧化物歧化酶）以及影响第二片上位叶渗透条件的小分子（如脯氨酸）含量。然而，与单独用硅或FN0603处理相比，硅和FN0603组合处理显著进一步提高了这些胁迫耐受指标，并最终显著促进了植株生长（<0.01），表明具有协同促进植物生长的作用。在处理过的植株根系中检测到菌株FN0603的相对丰度较高，硅进一步提高了FN0603在受胁迫小麦根系中的定殖。菌株FN0603特别是与硅组合存在时，改变了根内生细菌和真菌群落，而不是根际群落。二分网络分析、变异分割分析和结构方程模型进一步表明，菌株FN0603通过显著正向引导FN0603特异性生物标志物（<0.05）间接塑造根内生细菌和真菌群落，并改善植物生理、根际土壤性质和植物生长。硅和促植物生长微生物在缓解植物盐碱胁迫中塑造根内生菌群落的这种协同效应，可能为盐碱地可持续农业提供一种有前景的方法。
