Protists as main indicators and determinants of plant performance

Abstract

Background Microbiomes play vital roles in plant health and performance, and the development of plant beneficial microbiomes can be steered by organic fertilizer inputs. Especially well-studied are fertilizer-induced changes on bacteria and fungi and how changes in these groups alter plant performance. However, impacts on protist communities, including their trophic interactions within the microbiome and consequences on plant performance remain largely unknown. Here, we tracked the entire microbiome, including bacteria, fungi, and protists, over six growing seasons of cucumber under different fertilization regimes (conventional, organic, and Trichoderma bio-organic fertilization) and linked microbial data to plant yield to identify plant growth-promoting microbes. Results Yields were higher in the (bio-)organic fertilization treatments. Soil abiotic conditions were altered by the fertilization regime, with the prominent effects coming from the (bio-)organic fertilization treatments. Those treatments also led to the pronounced shifts in protistan communities, especially microbivorous cercozoan protists. We found positive correlations of these protists with plant yield and the density of potentially plant-beneficial microorganisms. We further explored the mechanistic ramifications of these relationships via greenhouse experiments, showing that cercozoan protists can positively impact plant growth, potentially via interactions with plant-beneficial microorganisms including Trichoderma, the biological agent delivered by the bio-fertilizer. Conclusions We show that protists may play central roles in stimulating plant performance through microbiome interactions. Future agricultural practices might aim to specifically enhance plant beneficial protists or apply those protists as novel, sustainable biofertilizers.

Seasonal Variations Affect The Ecosystem Functioning And Microbial Assembly Processes In Plantation Forests

“…These ndings suggest that seasonal variations had an additional in uence on soil microorganisms concerning different plant species, which is consistent with other studies [17,19,20,[23][24][25][26][27][28]. As an example, unlike other studies in which potential biotic and abiotic environmental variables such as soil moisture [29,30], plant types [31], pH [12,13,29,32], litter chemistry [33], and fertilization/season-induced changes [34] contributed to shaping the composition of the protist structures, our PERMANOVA pro ling revealed that the key factor driving the protist community's structure was peroxidase (POD) (Fig. 3).…”

“…It has also been shown that protist communities create a dynamic hub in soil biota [34,84]. As bacteria and fungi are principal prey for phagotrophic and/or consumer protists as the dominant soil protist functional group in soils [12,13,77,85,86], biotic interactions within the soil microbiome can in uence protist diversity. The taxon-speci c manner of protist taxa was observed for their potential microbial prey by detecting different and/or speci c links between bacteria/fungi and protist lineages.…”

“…The soil biota, mostly bacteria, fungi, and protists, is considered a key driver of primary production, nutrient cycling, and biogeochemical cycles [12,13]. Environmental factors such as plant species [9,14], physicochemical properties [9,11], and seasonal variations [5,[15][16][17] control the abundance and/or composition of soil biota.…”

Distinct Phyllosphere Microbiome of Wild Tomato Species in Central Peru Upon Dysbiosis

“…Eukaryotic microbial communities of wild tomatoes were mainly composed of Opisthokonta, representing a broad range of eukaryotes, such as fungi and protists. Thereby, protists have been identified as key determinants for plant performance (Guo et al 2021). The phylum Stramenopiles, including the foliar oomycete Phytophthora infestans (causal agent of late blight disease in tomato), was rarely detectable in Canta and low abundant in Yangas.…”

The Future of (Soil) Microbiome Studies: Current Limitations, Integration, and Perspectives

“…For example, we revealed that protists showed severe community fluctuations over time and due to fertilization, whereas communities of bacteria and fungi did not vary ( 15 ). We also revealed that bacterial and especially protistan communities and protistan species predict plant health unlike fungal communities ( 16 ). Therefore, microbiome studies should include multiple microbial groups, as otherwise misleading conclusions on bacterial community assembly, ecological patterns, or treatment effect sizes might be drawn.…”