Pramparo Romina Del Pilar, Vezza Mariana Elisa, Wevar Oller Ana Laura, Talano Melina Andrea, Agostini Elizabeth
Departamento de Biología Molecular, Facultad de Ciencias Exactas Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, 5800, Río Cuarto, Córdoba, CP, Argentina.
Instituto de Biotecnología Ambiental y Salud (INBIAS-CONICET). Río Cuarto, Córdoba, Argentina.
World J Microbiol Biotechnol. 2024 Dec 30;41(1):20. doi: 10.1007/s11274-024-04233-2.
Arsenic (As) contamination in agricultural groundwater and soil is a significant economic and health problem worldwide. It inhibits soybean (Glycine max (L.) Merr.) nodulation and biological nitrogen fixation in symbiosis with Bradyrhizobium japonicum E109 (E109), a commonly used rhizobial strain for commercial biofertiliser formulation in Argentina. In the context of sustainable and climate-smart agriculture promoted by FAO, co-inoculating legumes with As-tolerant plant growth-promoting bacteria (PGPB) is suggested as a superior alternative to single inoculation. This study aimed to evaluate the impact of As on plant growth-promoting (PGP) traits -siderophore and indole acetic acid production, phosphate solubilisation, diazotrophic activity and hydrolytic enzymes activity- in E109 and three other PGPB strains: Pseudomonas sp. AW4 (AW4), Bacillus pumilus SF5 (SF5) and Bacillus toyonensis SFC 500-1E (Bt). In addition, bacterial compatibility and adhesion on soybean seed were evaluated. Arsenic significantly reduced PGP traits of E109 even at low concentrations, AW4's traits remained unchanged, while those of SF5 and Bt traits were affected (positively or negatively) only at the highest concentrations tested (500 µM arsenate, 250 µM arsenite). All PGPB strains were compatible with E109 under both control and As-stress conditions. Soybean seed adhesion was reduced for E109, only under As stress. Findings suggest that the effect of As on PGP traits is highly strain-dependent and influenced by As concentration and speciation. AW4, SF5, and Bt strains show promise for co-inoculation with E109 in soybean cultivation.
农业地下水和土壤中的砷（As）污染是一个全球性的重大经济和健康问题。它会抑制大豆（Glycine max (L.) Merr.）与慢生根瘤菌E109（E109）共生时的结瘤和生物固氮，E109是阿根廷商业生物肥料配方中常用的一种根瘤菌菌株。在联合国粮食及农业组织倡导的可持续和气候智能型农业背景下，建议将耐砷植物促生细菌（PGPB）与豆科植物共同接种，作为单一接种的一种更好选择。本研究旨在评估砷对E109以及其他三种PGPB菌株（假单胞菌属AW4（AW4）、短小芽孢杆菌SF5（SF5）和东洋芽孢杆菌SFC 500 - 1E（Bt））的植物促生（PGP）特性（铁载体和吲哚乙酸产生、磷溶解、固氮活性和水解酶活性）的影响。此外，还评估了细菌在大豆种子上的兼容性和粘附性。即使在低浓度下，砷也会显著降低E109的PGP特性，AW4的特性保持不变，而SF5和Bt的特性仅在测试的最高浓度（500 μM砷酸盐、250 μM亚砷酸盐）下受到（正向或负向）影响。在对照和砷胁迫条件下，所有PGPB菌株都与E109兼容。仅在砷胁迫下，E109对大豆种子的粘附性降低。研究结果表明，砷对PGP特性的影响高度依赖菌株，并且受砷浓度和形态的影响。AW4、SF5和Bt菌株在大豆种植中与E109共同接种显示出前景。
