Microbial Consortia as Plant Biostimulants: Definition, Concept, Categories, and Regulation.

Microbial consortia include cellulolytic bacteria, fungi, yeasts, and microbial-based biofilms which can be found in, or constituents of, food products, soils, wastewater, etc. flourishing in nature. The characterization, design, and management of these consortia are feasible, and their application in diverse fields, such as agriculture, is under research. During the last decades, considerable attention has been paid to microbial consortia as plant bio stimulants. They are an ecological alternative for sustainable agriculture and a win-win strategy to grow valuable plants without releasing fertilizers and/or pesticides into the environment. Plant biostimulants are natural preparations, of a diverse class of substances and/or micro-organisms, which positively affect plant growth conditions, stimulate natural processes, improve yield and chemical composition, and increase tolerance to biotic and abiotic stress. The purpose of this chapter is to provide an up-to-date overview of microbial consortia used as plant biostimulants. Aiming to describe the emerging definitions of plant bio stimulants, their concept, the functional categories, and their potential application as a significant tool for modern eco-friend agriculture. The chapter focuses also on reporting the regulatory framework and the current market situation of plant bio stimulants, as well as their advances in research.