Food Security and Safety Niche, Faculty of Natural and Agricultural Sciences, Private Mail Bag X2046, North-West University, Mmabatho 2735, South Africa.
Food Security and Safety Niche, Faculty of Natural and Agricultural Sciences, Private Mail Bag X2046, North-West University, Mmabatho 2735, South Africa.
Microbiol Res. 2021 Jan;242:126640. doi: 10.1016/j.micres.2020.126640. Epub 2020 Nov 2.
Soybean (Glycine max L.) is among the most economically important legumes that provide more than 1/4 of food (for man) and animal feed. However, its yield is comparatively low, most especially under drought stress. The aim of this study therefore was to assess the ability of Rhizobium spp. and mycorrhizal fungi to enhance the yield, seed size and fatty acid content of soybean grown under semi-arid environment. Rhizobium sp. strain R1 was found to possess nitrogen-fixing gene coniferyl aldehyde dehydrogenase function while Rhizobium cellulosilyticum strain R3 was found to have nitrogen-fixing genes cysteine desulfurase SufS and cysteine desulfurase IscS activity. Soybean (Glycine max L) seeds inoculated with Rhizobium spp. and mycorrhizal fungi were cultivated in soil exposed to drought stress. Rhizobium spp. inoculation and mycorrhization alleviate drought stress and increase yield, size and fat content of soybean seeds. This increase in the aboveground parameters was accompanied with an increase in belowground mycorrhizal spore number, percentage root mycorrhization and aboveground shoot relative water content (RWC) in the dually inoculated (R1 + R3MY) soybean plants. In particular, the dually inoculated (R1 + R3MY) soybean plants revealed 34.3 g fresh weight, 15.1 g dry weight and soybean plants singly inoculated with Rhizobium sp. strain R1 (R1) produced more large seeds with 12.03 g dry weight. The non-inoculated (control) seeds contained a higher percentage of moisture content compared to the microbially amended seeds while seeds co-inoculated with Rhizobium cellulosilyticum strain R3 and mycorrhizal consortium revealed the highest percent (8.4 %) of fat. Several fatty acids that are of significant health benefits to humans were observed in the soybean seeds. In order to gain insights into the bacterial communities of rhizospheric soil collected at different stages of soybean growth, class-based Heat-map analysis was performed on the Miseq sequenced data. The core bacteria that were found in the rhizospheric soil were Verrumicrobia, Proteobacteria, Gemmatimonadetes, Firmicutes, Cyanobacteria, Chloroflexi, Bacteroidetes, Actinobacteria, Acidobacteria, Planctomycetes, Deinococcus thermus and Nitrospira suggesting that the rhizobia and fungi used in this study can also improve soil microbial diversity.
大豆（Glycine max L.）是最重要的经济作物之一，为人类提供了超过四分之一的食物（作为人类的食物）和动物饲料。然而，其产量相对较低，尤其是在干旱胁迫下。因此，本研究的目的是评估根瘤菌和菌根真菌增强在半干旱环境中生长的大豆产量、种子大小和脂肪酸含量的能力。发现根瘤菌菌株 R1 具有固氮基因松柏醛脱氢酶功能，而纤维素分解根瘤菌菌株 R3 具有固氮基因半胱氨酸脱硫酶 SufS 和半胱氨酸脱硫酶 IscS 活性。接种了根瘤菌和菌根真菌的大豆种子在暴露于干旱胁迫的土壤中进行了栽培。根瘤菌接种和菌根化缓解了干旱胁迫，增加了大豆种子的产量、大小和脂肪含量。这些地上参数的增加伴随着地下菌根孢子数量、根际菌根化百分比和地上茎相对含水量（RWC）的增加，在双重接种（R1 + R3MY）的大豆植株中。特别是，双重接种（R1 + R3MY）的大豆植株表现出 34.3 g 鲜重、15.1 g 干重，而单独接种根瘤菌菌株 R1（R1）的大豆植株产生更多的大种子，干重为 12.03 g。与微生物改良的种子相比，未接种（对照）的种子含有更高百分比的水分，而与纤维素分解根瘤菌菌株 R3 和菌根共生体共同接种的种子则显示出最高的脂肪百分比（8.4%）。在大豆种子中观察到几种对人类健康有重要益处的脂肪酸。为了深入了解不同大豆生长阶段采集的根际土壤中的细菌群落，对 Miseq 测序数据进行了基于类别的热图分析。在根际土壤中发现的核心细菌是 Verrumicrobia、Proteobacteria、Gemmatimonadetes、Firmicutes、Cyanobacteria、Chloroflexi、Bacteroidetes、Actinobacteria、Acidobacteria、Planctomycetes、Deinococcus thermus 和 Nitrospira，这表明本研究中使用的根瘤菌和真菌也可以提高土壤微生物多样性。
