**2. Sustainable agricultural system and its benefits**

The best agricultural system is the one that find a good balance between the need for food production and the preservation of the ecological system within the environment. Also, the agriculture that focuses on producing long-term crops and livestock with minimum adverse effects on the environment is called as sustainable agriculture [8]. Besides the production of food, some of the various objectives of sustainable agriculture include reducing the use of fertilizers and pesticides, promoting biodiversity in crops grown and the ecosystem, and conserving water. It also aimed at maintaining the economic stability of farms and improving farming techniques and quality of a farmer's life [9].

The various benefits of sustainable agriculture can be divided into human health benefits and environmental benefits. Regarding human health, crops grown through sustainable agriculture are better for people. People are not becoming ill by consuming synthetic materials present in chemical pesticides and fertilizers. In addition, these crops are also more nutritious because of their more natural production. Its positive impacts of the environment include use of less percentage of energy per unit of crop yield as compared to industrialized agriculture [10, 11]. This minimizes the release of harmful chemicals and thereby reduces pollution of environment. Other benefits to the environment are maintenance of soil quality, reduction in soil degradation and erosion, and saving water. It also increases biodiversity of the area by providing a variety of organisms surrounded with a healthy and natural environment (**Figure 1**) [12–14].

**21**

establishment [25].

*Arbuscular Mycorrhizal (AM) Fungi as a Tool for Sustainable Agricultural System*

The symbiotic association between a fungus and a root of higher plant is called as Mycorrhiza [15]. From this association, both of the partners, the host plant and the fungal member are benefited potentially [16]. There are several benefits provided by the Mycorrhizal fungi to the host plant species. Some of them are increased nutrient uptake, production of growth promoting substances, tolerance to drought, salinity and synergistic interactions with other beneficial

Endomycorrhiza i.e. Arbuscular Mycorrhizal (AM) symbiosis is formed by approximately 80% of all terrestrial plant species. Even the roots of some aquatic plants are colonized by AM fungi [19, 20]. AM fungi belong to the class Zygomycetes, order Endogonales, family Endogonaceae, and phylum Glomeromycota. The mycorrhizal associations are formed by the six genera of fungi belonging to Endogonaceae. These are Glomus, Gigaspora, Acaulospora, Entrophospora Sclerocystis and Scutellospora. Their common characteristic are spores and sporocarps which are formed mostly in the soil surrounding the roots

The most visible AM structure is the hyphal network. Hyphae are thin from 2 μm in diameter to >20 μm, hollow tubes of fungi having only few cross walls and distinct angular projections [22]. In search of the roots of host plants, these tubes originally grow from fungal spores, extending short distances into

Hyphae that penetrates a host root form a structure called an appressorium. It penetrates the cell wall of the root by mechanical pressure or through the enzymes that degrade the cell wall. Hyphae that enter host roots through these infection points can form networks both inside the root and throughout the soil surrounding the root. As the name suggests, the AM fungus colonizes the root cortex forming a mycelial network and characteristic bladder-like structures called as vesicles and branched finger-like hyphae called as arbuscules. Arbuscules are short-lived structures meant for nutrient transfer and absorptive function. The hyphal branch that penetrates the plant cell wall forms the arbuscules trunk. This arbuscule trunk branches repeatedly and is surrounded by the plasma membrane. The terminal swellings of the hyphae forms vesicles on both intercellular and intracellular

In the mutualistic association, the plant provides the fungus with photosynthetically derived carbohydrate, while the fungus supplies the plant roots with nutrients. Also, in this symbiotic association, there is a third component i.e., a bacterium that seems to be having a loose or tight association with the plants and the mycorrhizal fungi and play an important role in mycorrhizal function. So, there is a tripartite relationship among host plant, AM fungi and bacteria. This bacterium has been termed as 'helper bacteria' because it supports mycorrhizal

*DOI: http://dx.doi.org/10.5772/intechopen.94442*

**3. Mycorrhizal association**

microorganisms [17, 18].

**4. Arbuscular mycorrhizae**

and rarely inside the roots [21].

surfaces, and have storage as function [23, 24].

**4.1 As a tool for sustainable agriculture**

*4.1.1 Benefits from tripartite relationship*

the soil.

**Figure 1.** *Benefits of sustainable agriculture*

*Arbuscular Mycorrhizal (AM) Fungi as a Tool for Sustainable Agricultural System DOI: http://dx.doi.org/10.5772/intechopen.94442*
