###### Abstract  
Microbial interactions within the rhizosphere are fundamental to plant health, influencing nutrient availability, stress tolerance, and pathogen resistance. Beneficial microbes, such as plant growth-promoting microbes (PGPMs), including bacteria and mycorrhizal fungi, enhance plant resilience through mechanisms like nutrient solubilization, phytohormone production, and pathogen suppression via antimicrobial compounds and siderophores. Root exudates, composed of sugars, organic acids, and secondary metabolites, act as chemoattract that shape the rhizosphere microbiome by recruiting beneficial microbes. Microbial metabolites can, in turn, modulate plant physiology and exudate profiles, thereby reinforcing mutualistic interactions. Stress conditions alter exudate composition, enabling plants to attract specific microbes that aid in stress mitigation. Given the growing interest in microbiome-based agricultural solutions, this review aims to synthesize recent literature on plant-microbe interactions, with a focus on bidirectional signaling between plants and microbes. A structured literature search was conducted using databases such as PubMed, Scopus, and ScienceDirect to identify key studies on root exudation, microbial functions, and synthetic microbial communities (SynComs). We highlight major findings on how engineered microbiomes can enhance plant growth, resilience, and productivity, particularly under stress conditions. This review also explores how advances in SynCom design can promote sustainable agriculture by reducing reliance on chemical inputs. keywords: rhizosphere; root exudates; chemical signaling; SynComs; microbial engineering +
Footnote †: 2020: _Applied sciences_  
_Review_  
A Review of Plant-Microbe Interactions in the RThe plant microbiome plays a significant role in a plant's growth and development, and the development of bio-organic fertilizers is key to mitigating the effects of chemical fertilizers and improving soil health [5]. Soil health plays a critical role in this shift. The plant roots and soil microorganisms' interactions, particularly in the rhizosphere, are a key factor in mitigating stressors that impact plant health and productivity [6]. The term \"rhizosphere\" was coined by the German agronomist [PERSON] in 1904, describing the soil zone immediately surrounding the plant root, teeming with microorganisms influenced by chemicals released by roots [7]. Over a century of research has deepened our understanding of the rhizosphere and aimed to further define these root exudates and how they interact with and influence the soil microbiota. Sugars, organic acids, and secondary metabolites, synthesized and released into the soil through plant roots, influence the soil environment and act as a chemoattractant [8]. These chemical signals facilitate mutualistic relationships between plants and beneficial microorganisms, including plant growth-promoting bacteria (PGPB) and mycorrhizal fungi. These plant-microb interactions can reduce the effects of biotic and abiotic stressors, increase nutrient uptake, and ultimately increase the resiliency of plants [9]. In recent years, microbiome engineering has emerged as a promising approach to enhancing plant-microbe interactions and improving agricultural outcomes. Fertilizing plants with beneficial microbes dates to the late 18 th century, although the first commercial biofertilizer was released in 1895 [10]. The term \"SynCom\", referring to synthetic microbial communities, was first employed in 2019 [11]. Engineering microbial communities is a valuable tool in climate-smart agriculture. By customizing microbial communities to meet the needs of crops in particular environments, SynComs offers a strategy for developing more resilient agricultural systems capable of withstanding the challenges posed by climate change [12]. Despite significant progress in understanding plant-microbe interactions and microbiome engineering, several critical research gaps remain.