## 1 Introduction
Disease suppression not only refers to healthy soil containing a stable microbial community, but also to advantageous physical and chemical soil properties that enhance crop protection. Disease suppression can be viewed as a biological property of a soil conferred by its own microbiome because soil sterilization destroys or reduces its own capacity in disease controlling [29]. Suppression can be transferred between different soils when a disease-conducive soil (DCS) receives a fixed amount (1-10% by volume) of a DSS [30; 31]. The findings provided by [PERSON] et al. (1995) [32] and [PERSON] et al. (2020) [33] postulated that plant species tend to develop their defense strategies against soil-borne diseases through selective stimulation. The contribution of antagonistic microorganisms determines the suppressive potential of a soil [25; 34; 35]. DSS has the ability to suppress pathogens and diseases by integrated mechanisms such as improving plant fitness, inducing natural plant defense, producing antibiotics, competing against the pathogen and modulating the plant immunity systems or hyper-parasitizing the pathogen [25; 33; 35]. Comprehensive information on DSS is still lacking because soil is a complex dynamic ecosystem that provides nutrients to microbiota that can be defined as super-genomes in a specific habitat [36]. In fact, a teaspoonful of productive soil contains from 100 million to 1 billion organisms [37], where microorganisms are broadly classified into bacteria, archaea, fungi, algae, protozoa and nematodes that are the main drivers of fundamental ecological processes, ecosystem services and functions [37; 38; 39]. Advances describing the microbial communities have been accompanied by the use of specific terms such as \"microbiota\" and \"microbiome,\" whose definitions are still debated [40; 41]. In the present review, the term \"microbiota\" refers to all microorganisms interacting in a specific environment, in this case the soil, while \"microbiome\" encompasses the structural elements and molecules (i.e., genes and their transcripts, proteins and metabolites, etc.). As well, the environmental conditions associated with the microbiota were initially described by [PERSON] et al. (1988) [42], then clarified by [PERSON] et al. (2016) [43] and recently reviewed by [PERSON] et al. (2020) [41]. Studies on the interactions between soil microbiota and plants have attracted worldwide interest due to the need for restoration and maintenance of wide biodiversity, which is the priority issue in every conservation policy. Soil microbiota have been studied since the 1990s for their critical role in maintaining the integrity, function and sustainability of a suppressive soil system [44]. Similarly, microbiota play a crucial role in soil functioning and maintaining soil health, with the capacity to control pathogens and diseases [45]. About 21% of carbon (C) fixed through photosynthesis is excluded at the root surface level [46] where the soil microbes feed on it, so influencing their activity and biodiversity. By understanding the interactions between plants and microbiota we can help the exploitation and recruitment of selective beneficial microorganisms to protect the plant against pathogens [32; 33]. Although DSSs have been identified for almost 60 years [47], advancements in next-generation sequencing (NGS) have opened a new era in understanding their microbiomes [48]. The NGS technologies, such as metabarcoding (amplicon sequencing) and shotgun sequencing, have allowed to characterize in depth the soil microbiomes [29]. Amplicon sequencing has greater potentiality than culture-dependent techniques to enable the researcher to identify the fine microbiota with disease-suppressive properties in compost-amended soil [49]. In order to screen and identify how the beneficial microbiota can contribute to soil disease suppression, only by deciphering the rhizosphere microbiome can we know the direct and indirect mechanisms of action [22; 23].