The bacterial consortia promote plant growth and secondary metabolite accumulation in Astragalus mongholicus under drought stress

Abstract

Astragalus mongholicus is a widely used Traditional Chinese Medicine. However, cultivated A. mongholicus is often threatened by water shortage at all growth stage, and the content of medicinal compounds of cultivated A. mongholicus is much lower than that of wild plants. To alleviate drought stress on A. mongholicus and improve the accumulation of medicinal components in roots of A. mongholicus, we combined different bacteria with plant growth promotion or abiotic stress resistance characteristics and evaluated the role of bacterial consortium in helping plants tolerate drought stress and improving medicinal component content in roots simultaneously. Through the determination of 429 bacterial strains, it was found that 97 isolates had phosphate solubilizing ability, 63 isolates could release potassium from potash feldspar, 123 isolates could produce IAA, 58 isolates could synthesize ACC deaminase, and 21 isolates could secret siderophore. Eight bacterial consortia were constructed with 25 bacterial isolates with more than three functions or strong growth promoting ability, and six out of eight bacterial consortia significantly improved the root dry weight. However, only consortium 6 could increase the root biomass, astragaloside IV and calycosin-7-glucoside content in roots simultaneously. Under drought challenge, the consortium 6 could still perform these functions. Compared with non-inoculated plants, the root dry weight of consortium inoculated-plants increased by 120.0% and 78.8% under mild and moderate drought stress, the total content of astragaloside IV increased by 183.83% and 164.97% under moderate and severe drought stress, calycosin-7-glucoside content increased by 86.60%, 148.56% and 111.45% under mild, moderate and severe drought stress, respectively. Meanwhile, consortium inoculation resulted in a decrease in MDA level, while soluble protein and proline content and SOD, POD and CAT activities increased. These findings provide novel insights about multiple bacterial combinations to improve drought stress responses and contribute to accumulate more medicinal compounds.

Using Fungi in Artificial Microbial Consortia to Solve Bioremediation Problems

“…Although genetically modified strains are effective in bioremediation processes [ 11 ], their use is limited to laboratory studies due to minimizing the risks of environmental impact. Since there are no globally accepted regulatory documents that concern the spread of genetically modified organisms, the regulation of the development and release of genetically modified organisms varies in different countries, depending on the purposes of their use, extending from a complete ban on their import, release or use to allowing their use, subject to varying degrees of regulation.…”

“…Cell immobilization can also solve the instability problems of microbial consortia, since cellular communication can be more active in a confined space and positively affects the speed of bioremediation processes. At the same time, the inclusion of cells in gel matrices [ 52 , 77 , 108 ] simulates the development of a stabilized state of cells and the additional formation of biofilms [ 11 , 34 , 91 , 103 , 111 ].…”

“…The biodegrading microorganisms of various pollutants have recently generated particular interest in studies of consortia of microorganism cells with heterogeneous composition, which combine the different metabolic potentials of participants [ 8 , 9 , 10 ]. In most cases, natural consortia contain a significant number of different prokaryotic cells (bacteria and archaea) that form biofilms, which may include aerobic and anaerobic cells [ 11 ]. At the same time, the extremely interesting properties possessed by those variants of consortia are created by cells of these prokaryotic microorganisms (i.e., bacteria and archaea) and eukaryotic microorganisms (in particular, filamentous fungi and yeast), which are able to coexist and catalyze biodegradation and bioremediation processes [ 12 ].…”

Formulation and evaluation of Ocimum sanctum Linn containing carboxymethylcellulose and sorbitol based hydrogel

“…Sorbitol is frequently used in the cosmetics sector and is thought to have a low toxicity and environmental impact [ 10 ]. A recent study used a dibenzylidene sorbitol framework to construct pseudoephedrine, preventing the active pharmaceutical ingredients from being easily extracted for usage in illicit substances [ 11 ]. Sorbitol gels were pH-tolerant and effective at absorbing large volumes of polluted particles [ 12 ].…”

Drought stress modifies the community structure of root-associated microbes that improve Atractylodes lancea growth and medicinal compound accumulation

“…For examples, inoculation with endophytic Trichoderma citrinoviride ginseng (could) promote the biosynthesis of ginsenosides (Park et al, 2019). Inoculation with combination of particular strains of bacteria could improve the accumulation of astragaloside IV and calycosin-7-glucoside in the root of Astragalus mongholicus (Lin et al, 2022). Inoculation with Glomus mosseae promoted the concentration of glycyrrhizic acid, liquiritin, isoliquiritin, and isoliquiritigenin in the main root of liquorice (Glycyrrhiza uralensis) (Chen et al, 2017).…”