Application of Protists to Improve Plant Growth in Sustainable Agriculture

Abstract

Plant health and growth are largely dependent on root-associated microbiota. Several bacteria and fungi can provide important services to plants, such as nutrient mineralization or protection against diseases. To date, most of our knowledge is centered on bacterial and fungal taxa. This chapter presents protists as an essential yet often overlooked component of the rhizosphere microbiome, where they play a crucial role in structuring microbial populations. Protists are a keystone group, functioning as predators of bacteria and fungi. They exert a strong pressure on plant-associated microbial communities and shape their functional and phylogenetic composition. They further enhance nutrient turnover and activate bacterial genes needed for pathogen suppression. Protists offer thus new venues to manage plant-associated microbial communities to enhance their functionality and ability to support a high plant growth in agricultural context. This chapter presents the main functional groups of soil protists and explains their distribution and importance for soil fertility. Finally, their applications in biotechnological settings aiming at reducing pesticide and fertilizer input in sustainable agriculture, are discussed.