Departamento de Biología Molecular, FCEFQyN, Universidad Nacional de Río Cuarto, Ruta Nacional 36 Km 601, Río Cuarto, CP 5800, Córdoba, Argentina; Instituto de Biotecnología Ambiental y Salud (INBIAS - CONICET), Ruta Nacional 36 Km 601, Río Cuarto, CP 5800, Córdoba, Argentina.
Plant Physiol Biochem. 2020 Oct;155:85-92. doi: 10.1016/j.plaphy.2020.07.015. Epub 2020 Jul 26.
Certain metal (loid)-resistant bacteria that inhabit the rhizosphere have shown to improve plant growth and tolerance under toxic metal stress. In this study, we tested if six native, arsenic-resistant and plant growth promoting bacteria (PGPB) were able to enhance soybean (Glycine max L.) growth and modulate arsenic (As) uptake. As a previous work, we tested all single isolates and all possible binary combinations without arsenic stress to identify the combinations that would have the greatest plant growth promoting effect. In this study, a screening assay was performed with only five inoculation options selected after first stage (Pseudomonas sp. AW4, Pseudomonas sp. AW6, AW4+AW6, Rhodococcus sp. AW3+Pseudomonas sp. AW5 and Enterobacter sp. AW1+AW6). In both stages, inoculation was implemented by imbibition of soybean seeds with bacterial suspensions, and plant growth was carried out in pots using perlite as substrate in a chamber with controlled conditions. In the third stage, we performed similar assays, under As stress, using the three most promising inoculation options (AW4, AW6 and AW3+AW5). Treatments were performed by irrigation with 25 μM arsenite (As), 25 μM arsenate (As), 25 μM equimolar As/As solution or water (control). Biometric and biochemical parameters indicated that inoculation with Pseudomonas sp. AW4 significantly promoted soybean growth under As/As treatment and did not modified As accumulation pattern. Further field studies are needed to determine if some of these inoculation options are useful to improve in situ soybean growth under arsenic stress and could become a tool for the development of sustainable agriculture in As-impacted environments.
某些栖息在根际的耐金属（类）细菌已被证明能在有毒金属胁迫下提高植物的生长和耐受性。在这项研究中，我们测试了六种本土、砷抗性和植物生长促进细菌（PGPB）是否能够增强大豆（Glycine max L.）的生长并调节砷（As）的吸收。如前一项工作所述，我们在没有砷胁迫的情况下测试了所有的单一分离株和所有可能的二元组合，以确定具有最大植物生长促进效果的组合。在这项研究中，仅使用第一轮筛选出的五个接种选项进行了筛选试验（假单胞菌 AW4、假单胞菌 AW6、AW4+AW6、罗克福氏菌 AW3+假单胞菌 AW5 和肠杆菌 AW1+AW6）。在两个阶段，通过用细菌悬浮液浸润大豆种子来进行接种，在受控条件下的室内使用珍珠岩作为基质在盆中进行植物生长。在第三阶段，我们在砷胁迫下，使用三个最有希望的接种选项（AW4、AW6 和 AW3+AW5）进行了类似的试验。处理是通过用 25μM 亚砷酸盐（As）、25μM 砷酸盐（As）、25μM 等摩尔 As/As 溶液或水（对照）进行灌溉来进行的。生物计量和生化参数表明，在 As/As 处理下，接种假单胞菌 AW4 显著促进了大豆的生长，并且没有改变 As 的积累模式。需要进一步的田间研究来确定这些接种选项中的某些是否有助于在砷胁迫下改善原位大豆的生长，并成为在砷污染环境中发展可持续农业的工具。
