The Application of Arbuscular Mycorrhizal Fungi as Microbial Biostimulant, Sustainable Approaches in Modern Agriculture

Abstract

Biostimulant application can be considered an effective, practical, and sustainable nutritional crop supplementation and may lessen the environmental problems related to excessive fertilization. Biostimulants provide beneficial properties to plants by increasing plant metabolism, which promotes crop yield and improves the quality of crops; protecting plants against environmental stresses such as water shortage, soil salinization, and exposure to sub-optimal growth temperatures; and promoting plant growth via higher nutrient uptake. Other important benefits include promoting soil enzymatic and microbial activities, changing the architecture of roots, increasing the solubility and mobility of micronutrients, and enhancing the fertility of the soil, predominantly by nurturing the development of complementary soil microbes. Biostimulants are classified as microbial, such as arbuscular mycorrhizae fungi (AMF), plant-growth-promoting rhizobacteria (PGPR), non-pathogenic fungi, protozoa, and nematodes, or non-microbial, such as seaweed extract, phosphite, humic acid, other inorganic salts, chitin and chitosan derivatives, protein hydrolysates and free amino acids, and complex organic materials. Arbuscular mycorrhizal fungi are among the most prominent microbial biostimulants and have an important role in cultivating better, healthier, and more functional foods in sustainable agriculture. AMF assist plant nutrient and water acquisition; enhance plant stress tolerance against salinity, drought, and heavy metals; and reduce soil erosion. AMF are proven to be a sustainable and environmentally friendly source of crop supplements. The current manuscript gives many examples of the potential of biostimulants for the production of different crops. However, further studies are needed to better understand the effectiveness of different biostimulants in sustainable agriculture. The review focuses on how AMF application can overcome nutrient limitations typical of organic systems by improving nutrient availability, uptake, and assimilation, consequently reducing the gap between organic and conventional yields. The aim of this literature review is to survey the impacts of AMF by presenting case studies and successful paradigms in different crops as well as introducing the main mechanisms of action of the different biostimulant products.

Amino Acids Biostimulants and Protein Hydrolysates in Agricultural Sciences

“…Biostimulants are considered bioactive substances that are either inorganic or organic microorganisms that can increase crop performance when utilized in small quantities [ 1 ] as they can enhance both performance and growth as well as improve nutrient- and water-use efficiencies of different crops [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Amino acids have a dual function as building blocks for proteins and as providers of organic nitrogen, which can alleviate the negative impacts of drought and salt stress [ 9 ], and promote cell growth.…”

Mycorrhizal Biotechnology Reduce Phosphorus in the Nutrient Solution of Strawberry Soilless Cultivation Systems

“…Thus, AMF use in strawberry cultivation can function as an economically and environmentally viable fertilization technique [6].…”

The Roles of Plant-Growth-Promoting Rhizobacteria (PGPR)-Based Biostimulants for Agricultural Production Systems

“…Biostimulants can be used to complement the application of chemical inputs, including the utilization of beneficial rhizosphere microbiome like advantageous fungi and plant-growth-promoting rhizobacteria [ 1 , 2 , 3 ]. The major biostimulants effects on crops include improving the visual quality of final products, stimulating the immune systems of plants, inducing the biosynthesis of plant defensive biomolecules, removing heavy metals from contaminated soil, improving crop performance, reducing leaching, improving root development, improving seed germination, inducing tolerance to abiotic and biotic stressors, accelerating crop establishment, and promoting nutrient uptake and nutrient use efficiency [ 4 , 5 ].…”

“…It has been reported that microbial biostimulants can synthesize IAA, which can promote root branching and plant growth of the plants under both abiotic and biotic stresses [ 4 , 5 ]. Microbial biostimulants can alleviate salt stress as they are associated with a high level of IAA and can improve them in the re-establishing of favorable water potential gradients under water shortage conditions as well as increasing film hydration around the roots [ 1 , 2 , 3 , 4 , 5 ]. Both PGPR and plants have ACC-deaminase, which has the ability to reduce the concentration of ethylene in the root zone and roots, with PGPR-derived ACC-deaminases being able to decrease ethylene-induced inhibition by reducing root zone ethylene [ 12 , 13 , 14 ].…”