Faba bean is highly susceptible to many viral infections. Around 50 viruses, viz., faba bean necrotic yellows, bean leaf roll, bean yellow mosaic, broad bean mottle, and pea seed-borne mosaic viruses are the most economically important viruses that infect faba bean in Asia and Africa. We have discussed their ecology and epidemiology, as well as their transmission, sensitive assays available for detection, and appropriate control measures.

In recent years, the antimicrobial resistance to various synthetic or chemically formed antimicrobial agents in medicines and food products has been observed. The high preference of consumers for purchasing food products free from chemical preservatives has led to more exploration into using antimicrobial agents from natural sources like plants, fungi, algae, and bacteria. The marine ecosystem comprises microorganisms, plants, vertebrates, and invertebrates that are rich sources of diverse antimicrobial products and can be a significant potential for developing novel type therapeutic agents, as the major portion of the sea has still not yet been examined for the evaluation of natural molecules for their antimicrobial activity. Such marine ecological niches promise a great source of antibacterial agents against many drugresistant strains of pathogenic microorganisms. Among the marine source, marine algae are a diverse group of organisms that includes brown, red, and green algae that have been targeted over the last few years for the secondary metabolites and a broad range of natural molecules for a broad spectrum of bioactivities beneficial to humans. Such bioactive compounds and secondary products possess a broad range of biological activities of antibacterial, antiviral, and antifungal properties. The class of compounds derived from marine algae, such as polysaccharides, fatty acids, phenolic compounds, pigments, lectins, alkaloids, terpenoids, and halogenated compounds, would be a new emerging area for unconventional drugs. Such classes of compounds will share a potent ability to control new diseases or tackling against multi-resistant strains of pathogens.

About 80% of terrestrial plants formed mycorrhizal association with AMF. Mycorrhizal association stimulates the physiological and molecular reactions even at subcellular stage leading to modification of the structure of plant community which results in the enhancement of plant resistance against all types of biotic and abiotic stresses. Molecular methodologies have been used to identify the AMF at ecosystem level but for specific plant species only. In a sustainable agricultural system farmers used natural procedures to attain improved food quality and productivity without using fertilizers, decrease input costs, and prevent environmental pollution and its side effects. The importance of using AMF inoculation in the sustainable agriculture system depends on the role of AMF for improving plant growth by increasing nutrients and water uptake and also increasing stability of soil aggregates and enhanced soil fertility. AMF interacts with soil-borne pathogen and reduces their effect on plant by antagonism, mycoparasitism, and antibiosis. Further studies are required for better understanding about ecological importance of AMF at community and ecosystem levels. 221numbers of AMF and land plants dated back 460 million years (Redecker, 2002). The most important function of this association is the uptake of phosphorous by roots of higher plants and increased uptake of water by hyphae of fungi. Mycorrhizal association also stimulates the physiological and molecular reactions even at subcellular stage leading to modification of the structure of plant community which results in the enhancement of plant resistance against all types of biotic and abiotic stresses. Plants of the same or different species connected with the help of the hyphal network of mycorrhizal association and that is how the transfer of nutrients, releasing signal molecules related to defense proteins like lipochitooligosaccharides and strigolectones. To understand the physiological and taxonomy of fungi recent studies have been carried out (Saito, 2000; Kohout et al., 2014). These are the members of phylum Glomeromycota and obligate in nature (Redecker et al., 2000). Their role for agriculture ecosystems documented very well and can be utilized for the restoration of the forest ecosystem (Solaiman and Abbott, 2003, 2008; Brundrett and Nanjappa, 2013). ECM fungi also distributed extensively, but they only associated with 3% land plants (Smith and Read, 2008) and are members of the phylum Ascomycota and Basidiomycota (Hibbett et al., 2000). AMF rather than ectomycorrhizal fungi depend on plants for Carbon sources, but when they are symbiotically associated, both required 20–40% of C from the plant that is photosynthetically fixed (McNear, 2013).

Plant root and fungus combined, results in a single structure through which exchange of nutrients takes place. There are many other mycorrhizal species found in the rhizosphere of citrus plants, but the major AMF found is Glomus species. The mycorrhizal association is also helpful in maintaining yield of the citrus plant. The soil of citrus orchards has many communities of AMF instead of a single species. So, the root of the citrus plant may be colonized by more than one AMF at the same point, which indicates that the soil of citrus orchard is rich in diversity of AMF, and this will improve the nutrient's uptake and growth of a citrus plant. Citrus plants inoculated with mycorrhiza have more resistance against soil-borne pathogens and diseases than nonmycorrhizal plants. The mycorrhizal association releases the antibiotics in the soil which can control soil microorganisms such as nematodes and pathogenic fungi so the chances of infection reduced.

Microorganisms are significant in the deterioration and spoiling of foods and beverages. The traits of spoiled food include unpleasing flavor, odor, and texture. Microbes are significant in preparing fermented foods and drinks at home and in industrial sectors, even though they are harmful. To ferment dairy products and create alcoholic drinks, microbes are utilized. Microbes are necessary to create dairy products, including yogurt, curd, sour cream, buttermilk, and cheese. Fermented foods, probiotics, and alcoholic beverages are gaining popularity because of their delicious and healthful properties. This chapter highlights the numerous microorganisms employed in the industrial sector of food and beverage manufacturing and demonstrates the advantages of utilizing the following bacteria in the beverage industry.

106Plants have the ability to interact with their environment. Different biotic and abiotic stresses, for example drought, salinity, heat, cold, metals and nutrient imbalance, affect the development and growth of plants. Plants modify themselves morphologically, physiologically, and modulating their biochemistry to suppress impact of various stresses. Plant roots develop association with soil microbes for better growth in every situation. Roots of higher plants interact with hyphae of some fungi and form a mutualistic association known as mycorrhizal association. There are many types of this mycorrhizal association, but the most important ones are ectomycorrhiza and arbuscular mycorrhiza. Mycorrhizal association helps in improving plant growth and yield by increasing nutrients uptake and water absorption from fine particles of soil. The role of mycorrhizal association is not only beneficial for enhancing plant tolerance to various stresses but this interaction also responds to many other stresses of their host plant.

Microbial diversity is an essential aspect of any ecosystem on earth. Microorganisms are the most common and diversified population in the soil. A microbe is a microscopic organism that can be studied in a single-cell or colony. On the other hand, microbes have a positive or negative effect on their surroundings. Microbial diversity plays an essential role in bioremediation, which is the method of detoxifying or neutralizing radioactive waste into less harmful or non-toxic compounds by secreting various bacterial and fungal enzymes. In this chapter, we focus on (i) the impact of microbial diversity on detoxifying pollutants (bioremediation), (ii) microbial role in biofuel production, (iii) microbial role in ore leaching (bioleaching), (iv) microbial role in controlling biogeochemical cycles (v) microbial role in soil quality and agriculture improvement (vi)

304Bio-based modifications such as compost, farms manure, slurry biogas, vermicompost, green manures (GMs), biofertilizer, crop residues and crop cover are a valuable nutrient source to boost the attributes of growing and yielding, yield, nutrient absorption, rice quality, and soil fertility. Organic farming improves soil organic carbon, phosphorus content available, and enzymatic/microbial population behavior of the soil to make organic farming sustainable. The organic system becomes sustainable in the long term by preserving the soil and improving its fertility by guaranteeing future generations production potential. The use of farmyard manure (FYM) will increase the soil’s microbial activity. This microbial soil behavior is dependent on the soil’s ability to release, store, and supply plant nutrients. Product consistency is also deteriorated as a result of chemical contaminants entering the plant body and the food chain. The emerging scenario requires the adoption of practices that preserve soil health, maintain a sustainable production system, and provide quality food to meet people’s nutritional needs. Organic agriculture is a method to improve the sustainability of the rice-white cultivation system without detrimental impacts on natural resources and the environment.