Plants host a complex but taxonomically assembled set of microbes in their natural environment which confer several benefits to the host plant including stress resilience, nutrient acquisition and increased productivity. To understand and simplify the intricate interactions among these microbes, an innovative approach—Synthetic Microbial Community (SynCom)—is practiced, involving the intentional co-culturing of multiple microbial taxa under well-defined conditions mimicking natural microbiomes. SynComs hold promising solutions to the issues confronted by modern agriculture stemming from climate change, limited resources and land degradation. This review explores the potential of SynComs to enhance plant growth, development and disease resistance in agricultural settings. Despite the promising potential, the effectiveness of beneficial microbes in field applications has been inconsistent. Computational simulations, high-throughput sequencing and the utilization of omics databases can bridge the information gap, providing insights into the complex ecological and metabolic networks that govern plant–microbe interactions. Artificial intelligence-driven models can predict complex microbial interactions, while machine learning algorithms can analyze vast datasets to identify key microbial taxa and their functions. We also discuss the barriers to the implementation of these technologies in SynCom engineering. Future research should focus on these innovative applications to refine SynCom strategies, ultimately contributing to the advancement of green technologies in agriculture.

Climate change is aggravating soil salinity, causing huge crop losses around the globe. Multiple physiological and biochemical pathways determine the ability of plants to tolerate salt stress. A pot experiment was performed to understand the impact of proline levels, i.e., 0, 10, 20 mM on growth, biochemical and yield attributes of two pea (Pisum sativum L.) cultivars (cv. L-888 and cv. Round) under salt stress (150 mM) along with control (0 mM; no stress). The pots were filled with river-washed sand; all the plants were irrigated with full-strength Hoagland’s nutrient solution and grown for two weeks before application of salt stress. Foliar spray of proline was applied to 46-day-old pea plants, once a week till harvest. Data for various growth and physio-biochemical attributes were collected from 70-day-old pea plants. Imposition of salt stress significantly checked growth, gas exchange characteristics [net CO₂ assimilation rate (A), transpiration rate (E), stomatal conductance (g_s)], total soluble proteins, concentration of superoxide dismutase (SOD), shoot and root K⁺ and Ca²⁺ contents, while sub-stomatal CO₂ concentration (Ci), coefficient of non-photochemical quenching (_qN), non-photochemical quenching (NPQ), concentration of catalase (CAT) and peroxidase (POD), free proline, and shoot and root Na⁺ contents increased substantially. Foliar application of proline significantly improved growth, yield, A, g_s, activity of POD, and shoot and root K⁺ and Ca²⁺ contents, while decreased NPQ values in both pea cultivars under stress and non-stress conditions. Moreover, both pea cultivars showed significant differences as cv. Round exhibited a higher rate of growth, yield, gas exchange, soluble proteins, CAT activity, free proline, shoot and root K⁺ and Ca²⁺ contents compared to L-888. Hence, the outcomes of this study pave the way toward the usage of proline at 20 mM, and cv. Round may be recommended for saline soil cultivation.

The individual application of pure and active compounds such as methionine may help to address water scarcity issues without compromising the yield of wheat. As organic plant growth stimulants, amino acids are popularly used to promote the productivity of crops. However, the influence of the exogenous application of methionine in wheat remains elusive. The present investigation was planned in order to understand the impact of methionine in wheat under drought stress. Two wheat genotypes were allowed to grow with 100% field capacity (FC) up to the three-leaf stage. Twenty-five-day-old seedlings of two wheat genotypes, Galaxy-13 and Johar-16, were subjected to 40% FC, denoted as water deficit-stress (D), along with 100% FC, called control (C), with and without L-methionine (Met; 4 mM) foliar treatment. Water deficit significantly reduced shoot length, shoot fresh and dry weights, seed yield, photosynthetic, gas exchange attributes except for transpiration rate (E), and shoot mineral ions (potassium, calcium, and phosphorus) in both genotypes. A significant increase was recorded in superoxide dismutase (SOD), catalase (CAT), hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and sodium ions (Na⁺) due to water deficiency. However, foliar application of Met substantially improved the studied growth, photosynthetic, and gas exchange attributes with water deficit conditions in both genotypes. The activities of SOD, POD, and CAT were further enhanced under stress with Met application. Met improved potassium (K), calcium (Ca²⁺), and phosphorus (P) content. In a nutshell, the foliar application of Met effectively amended water deficit stress tolerance by reducing MDA and H₂O₂ content under water deficit conditions in wheat plants. Thus, we are able to deduce a positive association between Met-induced improved growth attributes and drought tolerance.

Mercury (Hg), arsenic (As), cadmium (Cd), lead (Pb) and other toxic heavy metals (HM) pose significant risks to the environment, negatively impacting the morpho-physiological and biological traits of plants. At present, toxic elements constitute a significant proportion of the food chain, exerting an impact on human health due to their mobility and biomagnification. The metal exclusion biological technique stands out for its robust performance, even when dealing with extremely low metal concentrations. Its eco-friendly nature and cost-effectiveness further enhance its value. Due to the exponential growth pattern of bacteria, these exhibit high metal persistence and are recommended for metal exclusion processes. Moreover, vacuoles like vesicles present in mycorrhizal fungi can hold extremely high levels of HM. Microbe-assisted phytoremediation primarily occurs through two mechanisms: through the direct provision of the essential nutrients and phytohormones, such as plant growth regulators, siderophores, enzymes, and mineral; or indirectly by modulating the metal detoxification process. This indirect mechanism involves microbes aiding in the accumulation and sequestration of metals in plants through the secretion of specific extracellular substances like organic acids, biosurfactants, and chelators. Moreover, the metal bioavailability and translocation in the rhizosphere are also altered via various mechanisms like acidification, precipitation, complexation or redox reactions. The understanding of the molecular and physiological processes underpinning the functions of arbuscular mycorrhizal fungi (AMF) in reducing HM toxicity, improving plant performance by procuring nutrients under HM-toxicity has significantly improved in recent years. In this review, adaptive and persistent methods related to physiological and cross-protective mechanisms in bacteria and mycorrhizal fungi (MF) resulting from the evolutionary consequences of dealing with HM toxicity have been addressed. Furthermore, the article offers details on the physiological and molecular reactions of host plants with fungi, and bacteria to HM stress, which may be useful for unveiling new knowledge about the strategies of HMs remediation.

Wastewater irrigation is a substitute for surface water scarcity, but traces of heavy metals (HMs) result in deleterious implications for soil, crop productivity, and in humans. Crops presenting HMs tolerance in genetic behavior are important for producing tolerant genotypes cultivated under wastewater irrigation. In the first part of this experiment, the results obtained previously are re-assessed in a hydroponic system and similar patterns and concentrations of HMs are found in different tomato organs. Following this trial, the tomato’s (Solanum lycopersicum L.) genetic basis of traits conferring HMs tolerance and yield are assessed when irrigated with waste or canal water. The North Carolina Mating II analysis illustrate the amount of gene action, nature, and inheritance pattern. Genetic components depict the involvement of non-additive, additive, and maternal genetic effects in HMs tolerance inheritance and yield. A noticeable increase in cumulative additive variance for the number of flowers (11,907.2) and the number of fruits (10,557.9) is recorded for tomato plants irrigated with wastewater, illustrating additive gene action. However, female and male (MSf/MSm) square ratios also show an association with cytoplasmic inheritance. For HMs tolerance, both additive and dominant variances appeared to be significant; cumulative dominance variance (4.83, 16.1, 4.69, 76.95, and 249.37) is higher compared to additive variance (0.18, 2.36, 0.19, −0.27, and 14.14) for nickel (Ni), chromium (Cr), lead (Pb), manganese (Mn), and zinc (Zn), respectively, indicating dominance gene action. The genotype RIOGRANDI accumulated and translocated fewer HMs to the aerial part of the plant compared to CLN-2418A and PB-017906, thus presenting a tolerant tomato genotype according to the hydroponic experiment. This also exhibited a differential pattern of gene action for HMs tolerance, suggesting that genotypes possess significant differences for HMs tolerance.