Microbial biostimulants: boosting plant performance and stress tolerance

Globally, food production and agricultural productivity are threatened by declining arable land for cultivation, rising human activities, and the effects of climate change, which presents regular floods, long-lasting droughts, and abrupt shifts in temperature. In addition, these climatic fluctuations exacerbate disease and insect occurrences, thus lowering agricultural productivity. Owing to these escalating environmental concerns, there is a great need for global collaboration and implementation of sustainable, ecologically secure and environmentally friendly agricultural techniques that enhance plant growth, stress tolerance and overall productivity. Microbial biostimulants (MBs) have emerged as a promising approach to enhance plant growth and development, even in stressful situations. These biostimulants comprise a diverse array of plant growth-promoting microorganisms (PGPMs) used separately or in combination, such as bacteria, fungi, and algae. This profoundly influences the growth, development, and stress responses of plants exposed to different environmental conditions. These microbes employ different mechanisms in mitigating different environmental stresses. However, each mechanism may vary depending on the specific microorganism-plant interaction and environmental conditions utilized. Hence, in this chapter, notable roles and potentials of MBs in revolutionizing plant performance and stress tolerance were highlighted. Also, the mechanisms by which these MBs operate were elucidated while their multifaceted interactions with plants were analyzed and their measures of ameliorating abiotic and biotic stresses. Additionally, the chapter analyzes the major challenges and prospects associated with the emerging adoption of these biostimulants, emphasizing the need for further research to optimize their application strategies and commercial viability.