Silicon and phosphorus are elements that are beneficial for plant growth. Despite the abundant availability of silicate and phosphate in the Earth's crust, crop nutritional requirements for silicon and phosphorus are normally met through the application of fertilizer. However, fertilizers are one of the major causes of heavy metal pollution. In our study, we aimed to assess silicate and phosphate solubilization by the bacteria Enterobacter ludwigii GAK2, in the presence and absence of phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), to counteract cadmium stress in rice (Oryza sativa L). Our results showed that the GAK2-treated rice plants, grown in soil amended with phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), had significantly reduced cadmium content, and enhanced plant growth promoting characteristics including fresh shoot and root weight, plant height, and chlorophyll content. These plants showed significant downregulation of the cadmium transporter gene, OsHMA2, and upregulation of the silicon carrier gene, OsLsi1. Moreover, jasmonic acid levels were significantly reduced in the GAK2-inoculated plants, and this was further supported by the downregulation of the jasmonic acid related gene, OsJAZ1. These results indicate that Enterobacter ludwigii GAK2 can be used as a silicon and phosphorus bio-fertilizer, which solubilizes insoluble silicate and phosphate, and mitigates heavy metal toxicity in crops.

中文翻译：

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镉胁迫下硅酸盐和磷酸盐增溶根际肠杆菌 Ludwigii GAK2 对水稻的影响。

硅和磷是对植物生长有益的元素。尽管地壳中有丰富的硅酸盐和磷酸盐，但作物对硅和磷的营养需求通常可以通过施肥来满足。然而，化肥是造成重金属污染的主要原因之一。在我们的研究中，我们旨在评估在存在和不存在磷酸盐 [Ca ₃ (PO ₄ ) ₂ ] 或硅酸盐 (Mg ₂ O ₈ Si _{3 ) 的情况下，细菌路德维氏}肠杆菌GAK2 对硅酸盐和磷酸盐的增溶作用，以抵消镉胁迫在大米（Oryza sativa升）。我们的结果表明，在用磷酸盐 [Ca ₃ (PO ₄ ) ₂ ] 或硅酸盐 (Mg ₂ O ₈ Si ₃ ) 改良的土壤中生长的经 GAK2 处理的水稻植株显着降低了镉含量，并增强了植物生长促进特性，包括鲜枝和根重、株高和叶绿素含量。这些植物表现出镉转运蛋白基因OsHMA2的显着下调和硅载体基因OsLsi1的上调。此外，GAK2 接种植物中的茉莉酸水平显着降低，茉莉酸相关基因的下调进一步支持了这一点，奥斯贾兹1。这些结果表明Enterobacter ludwigii GAK2 可以用作硅磷生物肥料，它可以溶解不溶性硅酸盐和磷酸盐，并减轻重金属对作物的毒性。