The most complex microhabitat is the rhizosphere, which is composed of a varied alliance of archaea, fungi, bacteria, and eukaryotes as well as an interconnected network of plant roots and soil. Crop yield and growth are directly affected by rhizosphere conditions. Plant development and yield were enhanced under nutrient-rich rhizosphere conditions. Most soils that require nurturing before or at the time of next harvest are drained by extensive agriculture. Fertilizers are the primary source of nutrients for crop. However, their extensive and unchecked use seriously threatens ecosystem stability and agricultural sustainability. These toxic substances accumulate in the soil, leak into water, and are discharged into the atmosphere, where they stay for decades and impart a vital risk to the ecosystem as a whole. The rhizosphere of plant growth-promoting rhizobacteria (PGPR) transforms a variety of vital nutrients such as nitrogen, phosphorus, zinc, and others that are unavailable to plants into forms that they can use. In order to interact with the valuable or pathogenic counterparts in the rhizosphere, PGPR produces a variety of hormones such as auxin, cytokinin, gibberellin, antimicrobial agents, secondary compounds, cell lytic enzymes, chitinases, proteases, hydrolases, stress- releasing materials 1-Aminocyclopropane-1-carboxylate deaminase, chelating siderophores, and certain signaling substances such as N-acyl homoserine lactone. PGPR can be used for rhizosphere engineering, which has several uses beyond crop fertilization, development of plant growth, sustainability, and environment friendly agriculture. There is an increasing concern regarding stress-resilient plant growth promoting. microorganisms (PGPM). This review paper covers the three elements of rhizosphere engineering with a particular emphasis on PGPM and how it might promote the appropriate use of rhizosphere engineering particularly in hosts, as an important aspect of environmentally conscious farming.

Medicinal and aromatic plants are valuable sources of herbal products worldwide due to their secondary metabolite content, high antioxidant activities and many other biological activities. As a result of the developing technology, the demand for natural active substances obtained from plants has increased. For use, plants collected from nature do not have the desired quality standards. For this reason, sustainability can be achieved by using microbial inoculants as well as many biotechnological and molecular approaches such as micro propagation, synthetic seed technology to increase the yield and quality standards of medicinal and aromatic plants. Thanks to microbial inoculants, yield increase can be realized and at the same time, product quality can be contributed due to increased soil quality. In this review, it was aimed to evaluate the important roles of plant growth promoting rhizobacteria (PGPR), Arbiscular mycorrhizal fungi and Trichoderma inoculants in increasing productivity, nutrient uptake and resistance of medicinal and aromatic plants to environmental stresses in the light of literature. In this review, the variation in the resistance of plants to environmental stresses is summarized by evaluating the ultimate effects of microbial inoculants alone and in combination. In addition, it has been added to the evaluation in studies to prevent the decrease of secondary metabolite content formed under environmental stress conditions in medicinal and aromatic plants by microorganisms.

Vermicompost products have gained a great importance in plant nutrition over the years. They are reported to have plant growth promoting effects both in horticulture and field crops. The nutritional value and chemical properties of vermicomposts highly depend on the feedstock used in their production. The aim of this study was to evaluate vermicompost manure, derived from the mixture of cattle manure and kitchen scraps, on seed germination and growth of tomato seedlings (Lycopersicon lycopersicum Mill.). Four solid vermicompost amendment rates of 0, 10, 20, and 30% were applied in plastic trays. Vermicompost application delayed and reduced seed emergence in all application rates, while in general, vermicompost substitution promoted growth tomato seedlings up to 20% of application rate. The results showed that vermicompost substitutions greater than 20% had adverse effects on seedling emergence and seedling growth parameters, which was attributed to high EC of vermicompost induced by cattle manure. Results suggest that both physical and chemical properties of the feedstock used for vermicompost production should be taken into consideration in order to sustain high vermicompost quality to ensure targeted plant growth for horticultural and agricultural purposes.

Medicinal and aromatic plants are valuable sources of herbal products worldwide due to their secondary metabolite content, high antioxidant activities and many other biological activities. As a result of the developing technology, the demand for natural active substances obtained from plants has increased. For use, plants collected from nature do not have the desired quality standards. For this reason, sustainability can be achieved by using microbial inoculants as well as many biotechnological and molecular approaches such as micro propagation, synthetic seed technology to increase the yield and quality standards of medicinal and aromatic plants. Thanks to microbial inoculants, yield increase can be realized and at the same time, product quality can be contributed due to increased soil quality. In this review, it was aimed to evaluate the important roles of plant growth promoting rhizobacteria (PGPR), Arbiscular mycorrhizal fungi and Trichoderma inoculants in increasing productivity, nutrient uptake and resistance of medicinal and aromatic plants to environmental stresses in the light of literature. In this review, the variation in the resistance of plants to environmental stresses is summarized by evaluating the ultimate effects of microbial inoculants alone and in combination. In addition, it has been added to the evaluation in studies to prevent the decrease of secondary metabolite content formed under environmental stress conditions in medicinal and aromatic plants by microorganisms.