Secretion Of Root Exudates Research Articles

Community metagenomics reveals the processes of cadmium resistance regulated by microbial functions in soils with Oryza sativa root exudate input

Plants exert a profound influence on their rhizosphere microbiome through the secretion of root exudates, thereby imparting critical effects on their growth and overall health. The results unveil that japonica rice showcases a remarkable augmentation in its antioxidative stress mechanisms under Cd stress. This augmentation is characterized by the sequestration of heavy metal ions within the root system and the prodigious secretion of a spectrum of flavonoids, including Quercetin, Luteolin, Apigenin, Kaempferide, and Sakuranetin. These flavonoids operate as formidable guardians, shielding the plant from oxidative damage instigated by Cd-induced stress. Furthermore, the metagenomic analyses divulge the transformative potential of flavonoids, as they induce profound alterations in the composition and structural dynamics of plant rhizosphere microbial communities. These alterations manifest through the recruitment of plant growth-promoting bacteria, effectively engineering a conducive milieu for japonica rice. In addition, our symbiotic network analysis discerns that flavonoid compounds significantly improved the positive correlations among dominant species within the rhizosphere of japonica rice. This, in turn, bolsters the stability and intricacy of the microenvironmental ecological network. KEGG functional analyses reveal a notable upregulation in the expression of flavonoid functional genes, specifically cadA, cznA, nccC, and czrB, alongside an array of transporters, encompassing RND, ABC, MIT, and P-ATPase. These molecular orchestrations distinctly demarcated the rhizosphere microbiome of japonica rice, markedly enhancing its tolerance to Cd-induced stress. These findings not only shed light on the establishment of Cd-resistant bacterial consortia in rice but also herald a promising avenue for the precise modulation of plant rhizosphere microbiomes, thereby fortifying the safety and efficiency of crop production.

Secretion of Root Exudates in Response to Biotic and Abiotic Environment

Secretion of Root Exudates in Response to Biotic and Abiotic Environment

Soil Bacterial Communities Across Seven Rhizoma Peanut Cultivars (Arachis glabrata Benth.) Respond to Seasonal Variation.

Soil microorganisms play key roles in soil nutrient transformations and have a notable effect on plant growth and health. Different plant genotypes can shape soil microbial patterns via the secretion of root exudates and volatiles, but it is uncertain how a difference in soil microorganisms induced by crop cultivars will respond to short-term seasonal variations. A field experiment was conducted to assess the changes in soil bacterial communities of seven rhizoma peanut (Arachis glabrata Benth, RP) cultivars across two growing seasons, April (Spring season) and October (Fall season). Soils' bacterial communities were targeted using 16S rRNA gene amplicon sequencing. Bacterial community diversity and taxonomic composition among rhizoma peanut cultivars were significantly affected by seasons, cultivars, and their interactions (p < 0.05). Alpha diversity, as estimated by the OTU richness and Simpson index, was around onefold decrease in October than in April across most of the RP cultivars, while the soils from Arblick and Latitude had around one time higher alpha diversity in both seasons compared with other cultivars. Beta diversity differed significantly in April (R = 0.073, p < 0.01) and October (R = 0.084, p < 0.01) across seven cultivars. Bacterial dominant taxa (at phylum and genus level) were strongly affected by seasons and varied towards more dominant groups that have functional potentials involved in nutrient cycling from April to October. A large shift in water availability induced by season variations in addition to host cultivar's effects can explain the observed patterns in diversity, composition, and co-occurrence of bacterial taxa. Overall, our results demonstrate an overriding effect of short-term seasonal variations on soil bacterial communities associated with different crop cultivars. The findings suggest that season-induced shifts in environmental conditions could exert stronger impacts on soil microorganisms than the finer-scale rhizosphere effect from crop cultivars, and consequently influence largely microbe-mediated soil processes and crop health in agricultural ecosystems.

Communication between plant roots and the soil microbiome; involvement in plant growth and development

AbstractRoot-associated microbial communities have strong influences on the health and development of plants. Through the secretion of root exudates, the soil microbiome is impacted by plants, thereby steering plant-soil reactions. Considering the importance of root exudates in the establishment of symbiotic associations in the rhizosphere, it is quite clear that understanding the interaction between plant roots and the soil microbiome may prove beneficial. Here, we review the interaction between plant root exudates and microbial communities in the soil. The influence of these bioactive molecules on the structure and function of soil microbes is also considered. We additionally, deliberate on how plants determine the soil microbiome and how they extract nutrients from endophytes for the augmentation of their growth and development. A good perspective of the communication between plant roots and the soil microbiome could lead to increased crop production, thereby limiting the need for synthetic fertilizers.

Collection of Alfalfa Root Exudates to Study the Impact of Di(2-ethylhexyl) Phthalate on Metabolite Production.

Root exudates are the main media of information communication and energy transfer between plant roots and the surrounding environment. The change in secretion of root exudates is usually an external detoxification strategy for plants under stress conditions. This protocol aims to introduce general guidelines for the collection of alfalfa root exudates to study the impact of di(2-ethylhexyl) phthalate (DEHP) on metabolite production. First, alfalfa seedlings are grown under DEHP stress in a hydroponic culture experiment. Second, the plants are transferred to centrifuge tubes containing 50 mL of sterilized ultrapure water for 6 h to collect root exudates. The solutions are then freeze-dried in a vacuum freeze dryer. The frozen samples are extracted and derivatized with bis(trimethylsilyl)) trifluoroacetamide (BSTFA) reagent. Subsequently, the derivatized extracts are measured using a gas chromatograph system coupled with a time-of-flight mass spectrometer (GC-TOF-MS). The acquired metabolite data are then analyzed based on bioinformatic methods. Differential metabolites and significantly changed metabolism pathways should be deeply explored to reveal the impact of DEHP on alfalfa in view of root exudates.

Plant Disease Resistance-Related Pathways Recruit Beneficial Bacteria by Remodeling Root Exudates upon Bacillus cereus AR156 Treatment.

The environmentally friendly biological control strategy that relies on beneficial bacterial inoculants to improve plant disease resistance is a promising strategy. Previously, it has been demonstrated that biocontrol bacteria treatments can change the plant rhizosphere microbiota but whether plant signaling pathways, especially those related to disease resistance, mediate the changes in rhizosphere microbiota has not been explored. Here, we investigated the complex interplay among biocontrol strains, plant disease resistance-related pathways, root exudates, rhizosphere microorganisms, and pathogens to further clarify the biocontrol mechanism of biocontrol bacteria by using plant signaling pathway mutants. Bacillus cereus AR156, which was previously isolated from forest soil by our laboratory, can significantly control tomato bacterial wilt disease in greenhouse and field experiments. Moreover, compared with the control treatment, the B. cereus AR156 treatment had a significant effect on the soil microbiome and recruited 35 genera of bacteria to enrich the rhizosphere of tomato. Among them, the relative rhizosphere abundance of nine genera, including Ammoniphilus, Bacillus, Bosea, Candidimonas, Flexivirga, Brevundimonas, Bordetella, Dyella, and Candidatus_Berkiella, was regulated by plant disease resistance-related signaling pathways and B. cereus AR156. Linear correlation analysis showed that the relative abundances of six genera in the rhizosphere were significantly negatively correlated with pathogen colonization in roots. These rhizosphere bacteria were affected by plant root exudates that are regulated by signaling pathways. IMPORTANCE Our data suggest that B. cereus AR156 can promote the enrichment of beneficial microorganisms in the plant rhizosphere by regulating salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) signaling pathways in plants, thereby playing a role in controlling bacterial wilt disease. Meanwhile, Spearman correlation analysis showed that the relative abundances of these beneficial bacteria were correlated with the secretion of root exudates. Our study reveals a new mechanism for SA and JA/ET signals to participate in the adjustment of plant resistance whereby the signaling pathways adjust the rhizosphere microecology by changing the root exudates and thus change plant resistance. On the other hand, biocontrol strains can utilize this mechanism to recruit beneficial bacteria by activating disease resistance-related signaling pathways to confine the infection and spread of pathogens. Finally, our data also provide a new idea for the in-depth study of biocontrol mechanisms.

The rhizosphere microbiome and host plant glucosinolates exhibit feedback cycles in Brassica rapa.

The rhizosphere microbiome influences many aspects of plant fitness, including production of secondary compounds and defence against insect herbivores. Plants also modulate the composition of the microbial community in the rhizosphere via secretion of root exudates. We tested both the effect of the rhizosphere microbiome on plant traits, and host plant effects on rhizosphere microbes using recombinant inbred lines (RILs) of Brassica rapa that differ in production of glucosinolates (GLS), secondary metabolites that contribute to defence against insect herbivores. First, we investigated the effect of genetic variation in GLS production on the composition of the rhizosphere microbiome. Using a Bayesian Dirichlet-multinomial regression model (DMBVS), we identified both negative and positive associations between bacteria from six genera and the concentration of five GLS compounds produced in plant roots. Additionally, we tested the effects of microbial inoculation (an intact vs. disrupted soil microbiome) on GLS production and insect damage in these RILs. We found a significant microbial treatment × genotype interaction, in which total GLS was higher in the intact relative to the disrupted microbiome treatment in some RILs. However, despite differences in GLS production between microbial treatments, we observed no difference in insect damage between treatments. Together, these results provide evidence for a full feedback cycle of plant-microbe interactions mediated by GLS; that is, GLS compounds produced by the host plant "feed-down" to influence rhizosphere microbial community and rhizosphere microbes "feed-up" to influence GLS production.

Plant growth-promoting rhizobacteria (PGPR) and its mechanisms against plant diseases for sustainable agriculture and better productivity

Plant growth-promoting rhizobacteria (PGPR) are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to, regulate the microbial dynamics and their interactions with the plants. These bacteria viz., Agrobacterium, Arthobacter, Azospirillum, Bacillus, Burkholderia, Flavobacterium, Pseudomonas, Rhizobium, etc., play important role in plant growth promotion. In addition, such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial, fungal and viral pathogens. The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic, siderophore, and hydrolytic enzymes, competition for space and nutrients, and quorum sensing whereas, indirect mechanisms include rhizomicrobiome regulation via. secretion of root exudates, phytostimulation through the release of phytohormones viz., auxin, cytokinin, gibberellic acid, 1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz., phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenyloxidases (PPO), superoxide dismutase (SOD), chitinase and β-glucanases. For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering. In addition, understandings of different strategies to improve PGPR strains, their competence, colonization efficiency, persistence and its future implications should also be taken into consideration.

Response of microbial community composition and function to emergent plant rhizosphere of a constructed wetland in northern China

To understand the mechanisms by which emergent plants influence the microbial communities in wetland sediments, we analyzed the response of microbial composition, abundance, metabolic activity, and metabolic genes to three emergent plant species [Cyperus alternifolius L. (Cyp), Typha angustifolia L. (Typ), and Phragmites australis (Cav.) Trin. ex Steud. (Phr)], and determined the important physicochemical properties of the soils and root exudates in Zhaoniu River Constructed Wetland in northern China. We found the composition of both the microbial communities and the metabolic genes differed between rhizosphere and non-rhizosphere sediments. The rhizosphere microbial abundance in Phr in summer was significantly higher than in the other two plants and in the non-rhizosphere. The rates of microbial respiration and ammonia oxidation in rhizosphere sediments were significantly higher than those in non-rhizosphere sediments. Our statistical analyses showed that the total organic carbon (TOC) concentration in root exudates and the oxidation–reduction potential (ORP) significantly influenced the differences in the composition, abundance, and metabolic activities of the microbial community and metabolic genes between rhizosphere and non-rhizosphere sediments, suggesting that the secretion of root exudates and oxygen by emergent plants was the main mechanism affecting the composition and function of the microbial community. As the result of the high levels of TOC and the ORP, the rhizosphere sediments showed relatively high abundances of the genes related to biodegradation of xenobiotic compounds. By contrast, non-rhizosphere sediments showed relatively high abundances of genes related to carbon fixation and sulfate reduction, possibly due to the low levels of TOC and ORP. Plants with an enhanced ability to secrete root exudates and oxygen, such as Phr, should be preferred in constructed wetlands to increase the metabolic activity of sediment microbial communities. This study extends our understanding of the mechanisms by which the plant rhizosphere affects the ecological functions of wetlands.

Specific and conserved patterns of microbiota-structuring by maize benzoxazinoids in the field

BackgroundPlants influence their root and rhizosphere microbial communities through the secretion of root exudates. However, how specific classes of root exudate compounds impact the assembly of root-associated microbiotas is not well understood, especially not under realistic field conditions. Maize roots secrete benzoxazinoids (BXs), a class of indole-derived defense compounds, and thereby impact the assembly of their microbiota. Here, we investigated the broader impacts of BX exudation on root and rhizosphere microbiotas of adult maize plants grown under natural conditions at different field locations in Europe and the USA. We examined the microbiotas of BX-producing and multiple BX-defective lines in two genetic backgrounds across three soils with different properties.ResultsOur analysis showed that BX secretion affected the community composition of the rhizosphere and root microbiota, with the most pronounced effects observed for root fungi. The impact of BX exudation was at least as strong as the genetic background, suggesting that BX exudation is a key trait by which maize structures its associated microbiota. BX-producing plants were not consistently enriching microbial lineages across the three field experiments. However, BX exudation consistently depleted Flavobacteriaceae and Comamonadaceae and enriched various potential plant pathogenic fungi in the roots across the different environments.ConclusionsThese findings reveal that BXs have a selective impact on root and rhizosphere microbiota composition across different conditions. Taken together, this study identifies the BX pathway as an interesting breeding target to manipulate plant-microbiome interactions.4atbM_n1-Xmh1rBaQ1rPHqVideo

Root exudates ameliorate cadmium tolerance in plants: A review

In the past few decades, cadmium (Cd) as soil contaminant is a major problem for the mankind. Cd contamination of soil and food crops is a critical environmental concern as it deteriorates the soil quality and creates threat to the food safety and human health. High Cd concentration in soils pose negative effects on the plants at physiological, structural and molecular levels. Secretion of certain secondary metabolites in the rhizosphere is a survival mechanism adopted by plants to tolerate and encounter Cd toxicity. Under metal-stressed conditions, secretion of root exudates in soil increases the external detoxification strategies of the plants. The secreted phytochemicals are gaseous compounds, inorganic and especially organic in composition. In plants, the role of these metabolites to confront Cd toxicity and induce tolerance under Cd distress is underrated. The review paper focuses on Cd sources, factors that affect its bioavailability, uptake and toxicity in the plants. Furthermore, it also highlights the contemporary progression in our understanding on the mechanisms of root exudation in plants and the effect of Cd toxicity on the root exudation. Finally, the review provides important information on the role of different root exudates to subsist Cd stress in plants naturally, particularly by reducing the dependence on synthetic amendments to enhance Cd-tolerance and its aquisition in plants.

Advances in the mechanism of cereal/legume intercropping promotion of symbiotic nitrogen fixation

Biological nitrogen fixation by rhizobia in symbiotic association with legumes is a valuable N source for agroecosystems, and thus it is crucial for increased sustainability of agricultural production. Previous studies found that legume and cereal intercropping can promote symbiotic nitrogen fixation mainly due to rhizosphere nitrogen depletion by the cereal and that soil mineral nitrogen is absorbed more by cereals than legumes, which forces the legume to increase its reliance on symbiotic nitrogen fixation. However, in addition to the nitrogen depletion theory in the rhizosphere, stoichiometry (such as nitrogen and phosphorus coupling) and molecular regulation mechanisms are also important in understanding legume nitrogen fixation. The legume usually maintains a stable stoichiometric relationship between nitrogen and phosphorus. Symbiotic nitrogen fixation of legumes tends to have a high demand for phosphorus, mainly because nitrogen fixation by legumes is a high energy-consuming process, and the required energy is directly provided by ATP. Therefore, when the phosphorus obtained by the intercropped legume is insufficient to meet the increase in symbiotic nitrogen fixation, legume growth is limited by phosphorus. Under phosphorus limitation, the phosphorus uptake strategy of the legume can be stimulated, i.e. by increasing the infection of arbuscular mycorrhizal fungi (AMF) and secretion of root exudates. The AMF mycelia of legumes can extend beyond the rhizosphere, linking the roots to the surrounding soil microhabitats and expanding the area of phosphorus absorbed by the roots. On the other hand, mobilizing rhizosphere insoluble phosphorus through root exudates is also an important pathway for improving phosphorus utilization. Increased soil phosphorus availability promotes plant growth and increased allocation of carbon (C) sources to roots and nodules, resulting in a larger root system or greater nodule formation, finally higher symbiotic nitrogen fixation. In addition, the formation of root nodules is influenced by rhizosphere talk between the cereal and legume, which are directly related to the level of nitrogen. A recent study found that under low N concentration conditions, cereal root exudates stimulated flavonoid biosynthesis and secretion partly through upregulating expression of the Chalcone-flavanone isomerase gene ( CFI ) in legumes. Meanwhile, an auxin-responsive GH3 family gene ( GH3.1 ) and the nodulation gene ENODL2 displayed significant increases, suggesting that nodulation continues under the regulation of auxin signaling and the nodulin-like protein. At nodule maturity, cereal root exudates continue to up-regulate key nodulation genes, such as NODL4 , ENOD93 and the N fixation gene FixI3 , finally promoting symbiotic nitrogen fixation. Moreover, a high concentration of soil mineral N significantly suppressed expression of the early nodulin gene NIN in Lotus corniculatus , which inhibited nodulation and symbiotic nitrogen fixation. In the cereal/legume intercropping system, rhizosphere nitrogen depletion can relieve the inhibition of nitrate on the expression of key nodulation and N fixation genes, thus promoting nodulation and symbiotic nitrogen fixation. In conclusion, intercropping can promote nitrogen uptake and optimize nitrogen use efficiency through the coupling effects of rhizosphere nitrogen depletion, phosphorus mobilization and the regulation of nitrogen fixation genes. This review will help improve our understanding of the mechanism of symbiotic nitrogen fixation in the cereal/legume intercropping system.

Stable isotope fractionation of zinc and cadmium in soil-plant system: A review

Stable isotope fractionation provides a useful tool for tracing the transfer of zinc (Zn) and cadmium (Cd) in the soil-plant system. Isotope fractionation processes include equilibrium fractionation, e.g. dissolution, complexation, precipitation, and kinetic fractionation, e.g. diffusion and evaporation. Therefore, isotope fractionation of metallic element can be used to study the mechanisms of metal translocation in biogeochemical cycling. With the development of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS), Zn and Cd isotopic composition in soil and plant samples can be accurately measured. The determination of Zn and Cd stable isotope ratios usually includes sample digestion, purification and mass discrimination correction. In the soil-plant system, plants are generally enriched with heavy Zn isotopes in comparison to soils, while roots are enriched with heavy Zn isotopes in comparison to shoots. For Cd, shoots are likely to be isotopically heavier than roots. The transport processes of Zn/Cd in the soil-plant system mainly involve transport in rhizosphere, root uptake and transport within plants. The adsorption and desorption of Zn/Cd by soil minerals can affect the metal mobility and the isotope fractionation between soil solid phases and soil solution. Heavy Zn isotopes are likely to be complexed, while light Zn isotopes are more mobile in soil solution. Conversely, soil minerals tend to adsorb light Cd isotopes, thereby resulting in an enrichment with heavy isotopes in the soil solution. Among the rhizospheric processes, the secretion of root exudates and the changes in pH also have an impact on the speciation and translocation of heavy metals, which lead to the release of heavy Zn isotopes into soil solution. Root uptake process is of pivotal importance for the determination of the isotopic composition of the whole plant. The diffusion of Zn2+ from the soil solution to the root surface leads to a light isotopes enrichment in plant. Heavy Zn isotopes are preferentially chelated or precipitated in the root apoplast. During the transport across the root cell membranes, the low-affinity transport leads to an enrichment with light isotopes in plant, while the high-affinity transport generates little or no isotope fractionation. Specific transporter of Cd in roots has never been found yet. Therefore, Cd may be took up mainly through low-affinity transport systems and thus be enriched in light isotopes in plants. The isotope fractionation between roots and shoots is related to the sequestration of Zn/Cd in roots and the xylem transport processes. The functional groups containing oxygen and nitrogen of organic acids in plant roots tend to chelate heavy Zn isotopes, with subsequent compartmentation in root vacuoles. The light Zn isotopes could be then loaded by the xylem and transferred to the aboveground parts. Interestingly, the intensity of isotope fractionation is mainly related to the transport distance in the xylem. Contrary to Zn, light Cd isotopes mainly bind to the thiol groups in roots, leading to the enrichment in heavy isotopes in shoots. The different behaviors between Zn and Cd in isotope fractionation in the soil-plant system could reflect the distinct accumulation and tolerance mechanisms of plants in response to Zn or Cd stress.

Phosphorus Release by Low Molecular Weight Organic Acids from Low-Grade Indian Rock Phosphate

Low molecular weight organic acids (LMWOAs) are naturally occurred in soil, particularly in the rhizosphere due to microbial metabolites and secretion of root exudates. Various functional groups present in LMWOAs can play an effective role in phosphorus dissolution. In this study, potentiality of LMWOAs for phosphorous release from low-grade Indian rock phosphates (RPs) collected from Udaipur, Jhabua and Purulia was investigated under laboratory conditions. The characteristic of P release and the factors influencing P release from selected low-grade RPs by using seven LMWOAs along with two inorganic acids were also investigated. The amount of P release from RPs with different acids at various concentrations and equilibrium pH as well as the different factors of P release was also compared. Results showed that the average amounts of P released by all the organic acids from the three RPs increased with the concentration of organic acids. The amount of P release by the organic acids from the RPs followed the order, i.e. oxalic acid > citric acid > tartaric acid > formic acid > malic acid > succinic acid > acetic acid. A negative correlation was observed between P released from RPs and an equilibrium solution pH. The average amounts P released from all sources of RP ranged from 12 to 81 mmol P kg−1 by acetic acid and citric acid respectively. In addition, the nature of RPs, RP/acid solution ratio, leaching time and temperature significantly influenced the P release from RPs by organic acids. Thus, the LMWOAs could be a potential amendment for improving bio availability of P from RP.

Stimulation of nitrogen removal in the rhizosphere of aquatic duckweed by root exudate components

Plants can stimulate bacterial nitrogen (N) removal by secretion of root exudates that may serve as carbon sources as well as non-nutrient signals for denitrification. However, there is a lack of knowledge about the specific non-nutrient compounds involved in this stimulation. Here, we use a continuous root exudate-trapping system in two common aquatic duckweed species, Spirodela polyrrhiza (HZ1) and Lemna minor (WX3), under natural and aseptic conditions. An activity-guided bioassay using denitrifying bacterium Pseudomonas fluorescens showed that crude root exudates of the two species strongly enhanced the nitrogen-removal efficiency (NRE) of P. fluorescens (P < 0.05) under both conditions. Water-insoluble fractions (F) obtained under natural conditions stimulated NRE to a significant extent, promoting rates by about 30 %. Among acidic, neutral and basic fractions, a pronounced stimulatory effect was also observed for the neutral fractions from HZ1 and WX3 under both conditions, whereas the acidic fractions from WX3 displayed an inhibitory effect. Analysis of the active fractions using gas chromatography/mass spectrometry (GC/MS) revealed that duckweed released fatty acid methyl esters and fatty acid amides, specifically: methyl hexadecanoate, methyl (Z)-7-hexadecenoate, methyl dodecanoate, methyl-12-hydroxystearate, oleamide, and erucamide. Methyl (Z)-7-hexadecenoate and erucamide emerged as the effective N-removal stimulants (maximum stimulation of 25.9 and 33.4 %, respectively), while none of the other tested compounds showed stimulatory effects. These findings provide the first evidence for a function of fatty acid methyl esters and fatty acid amides in stimulating N removal of denitrifying bacteria, affording insight into the “crosstalk” between aquatic plants and bacteria in the rhizosphere.

Manipulating the soil microbiome to increase soil health and plant fertility

A variety of soil factors are known to increase nutrient availability and plant productivity. The most influential might be the organisms comprising the soil microbial community of the rhizosphere, which is the soil surrounding the roots of plants where complex interactions occur between the roots, soil, and microorganisms. Root exudates act as substrates and signaling molecules for microbes creating a complex and interwoven relationship between plants and the microbiome. While individual microorganisms such as endophytes, symbionts, pathogens, and plant growth promoting rhizobacteria are increasingly featured in the literature, the larger community of soil microorganisms, or soil microbiome, may have more far-reaching effects. Each microorganism functions in coordination with the overall soil microbiome to influence plant health and crop productivity. Increasing evidence indicates that plants can shape the soil microbiome through the secretion of root exudates. The molecular communication fluctuates according to the plant development stage, proximity to neighboring species, management techniques, and many other factors. This review seeks to summarize the current knowledge on this topic.