Yeasts as Biofertilizers and Biocontrol Agents: Mechanisms and Applications.

Abstract

Yeasts, a large and diverse group of microorganisms, are gaining increasing interest from both the scientific community and industry. Yeasts' natural association with plants has endowed them with a broad repertoire of mechanisms that facilitate a beneficial coexistence. Despite the ability of certain yeast species to enhance plant growth and demonstrate broad-spectrum antifungal activities, their commercialization remains limited. This mini-review focuses on recent insights into the mechanisms by which yeasts stimulate plant growth and protect plants from certain diseases. Yeast species support plant growth by increasing the supply or availability of essential nutrients or by producing phytohormones. The mode of action of yeasts as biological control agents includes competition for nutrients and space, mycoparasitism, formation of biofilms that inhibit pathogen growth, and production of killer toxins, hydrolytic enzymes, and volatile organic compounds. Additionally, yeasts can induce systemic resistance in host plants by enhancing defensive enzyme activity or upregulating pathogenesis-related gene expression. This mini-review explores the current and future applications of yeasts as biofertilizers and biocontrol agents, emphasizing the metabolic engineering of yeast strains and the engineering of plant microbiomes.