DataSheet1_Effect of a Bacillus velezensis and Lysinibacillus fusiformis-based biofertilizer on phosphorus acquisition and grain yield of soybean.pdf

IntroductionPhosphate-solubilizing bacteria that function through acidification (organic acid synthesis) or mineralization (production of enzymes such as phytase and phosphatases) have been explored as a biotechnological alternative to enhance plant access to phosphorus (P) retained in organic and inorganic forms in agricultural soils. This study tested the hypothesis that applying a biofertilizer composed of a recognized phosphate-solubilizing bacterium (Bacillus velezensis – endophytic strain BVPS01) and an underexplored plant growth-promoting bacterium (Lysinibacillus fusiformis – endophytic strain BVPS02) would improve the growth and grain yield of Glycine max L. plants.
MethodsInitial in vitro tests assessed the functional traits of these bacteria, and a mix of strains BVPS01 and BVPS02 was produced and tested under field conditions to evaluate its agronomic efficiency.
ResultsThe results confirmed the hypothesis that the tested biofertilizer enhances the agronomic performance of G. max plants in the field. The B. velezensis strain (BVPS01) was found to be more effective than the L. fusiformis strain (BVPS02) in solubilizing phosphates via the phosphatase enzyme production pathway, indicated by the expression of the phoC and phoD genes. In contrast, L. fusiformis was more effective in solubilizing phosphates through organic acid and phytase-related pathways, in addition to synthesizing indole-3-acetic acid and increasing the mitotic index in the root meristem of G. max plants. These strains exhibited biological compatibility, and the formulated product based on these rhizobacteria enhanced root development and increased the number of nodules and flowers, positively affecting 1000-grain weight, grain yield, and grain P content.
DiscussionThus, the tested biofertilizer demonstrated potential to improve root growth and increase both the yield and quality of soybean crops, making it a sustainable and low-cost strategy.

引言：通过酸化作用（有机酸合成）或矿化作用（合成植酸酶、磷酸酶等酶类）发挥功能的解磷细菌（phosphate-solubilizing bacteria），已被开发为生物技术替代方案，以提升作物对农业土壤中有机与无机态滞留磷（P）的生物利用效率。本研究验证了如下假说：施用由公认解磷细菌——贝莱斯芽孢杆菌（Bacillus velezensis）内生菌株BVPS01——与尚未被充分研究的植物生长促生细菌——纺锤形赖氨酸芽孢杆菌（Lysinibacillus fusiformis）内生菌株BVPS02——组成的生物肥料，可提升大豆（Glycine max L.）植株的生长性能与籽粒产量。

试验方法：首先通过体外试验评估了上述两类细菌的功能性状，随后制备了BVPS01与BVPS02的复合菌剂，并在田间条件下开展试验以评价其农艺效率。

试验结果：本研究结果证实了所提出的假说，即受试生物肥料可提升田间大豆植株的农艺表现。研究发现，贝莱斯芽孢杆菌BVPS01相较于纺锤形赖氨酸芽孢杆菌BVPS02，更能通过磷酸酶产酶途径介导磷素溶解，该结论可通过phoC与phoD基因的表达得到佐证。与之相对，纺锤形赖氨酸芽孢杆菌则更擅长通过有机酸与植酸酶相关途径溶解磷素，此外还可合成吲哚-3-乙酸，并提升大豆植株根尖分生组织的有丝分裂指数。两类菌株展现出良好的生物学相容性，基于这些根际细菌（rhizobacteria）配制的产品可促进根系发育，增加根瘤与花的数量，进而对千粒重、籽粒产量及籽粒磷含量产生积极影响。

讨论：综上，受试生物肥料展现出促进大豆根系生长、提升作物产量与籽粒品质的潜力，是一种可持续且低成本的农业种植策略。