A Model to Explain Plant Growth Promotion Traits: A Multivariate Analysis of 2,211 Bacterial Isolates

Abstract

Plant growth-promoting bacteria can greatly assist sustainable farming by improving plant health and biomass while reducing fertilizer use. The plant-microorganism-environment interaction is an open and complex system, and despite the active research in the area, patterns in root ecology are elusive. Here, we simultaneously analyzed the plant growth-promoting bacteria datasets from seven independent studies that shared a methodology for bioprospection and phenotype screening. The soil richness of the isolate's origin was classified by a Principal Component Analysis. A Categorical Principal Component Analysis was used to classify the soil richness according to isolate's indolic compound production, siderophores production and phosphate solubilization abilities, and bacterial genera composition. Multiple patterns and relationships were found and verified with nonparametric hypothesis testing. Including niche colonization in the analysis, we proposed a model to explain the expression of bacterial plant growth-promoting traits according to the soil nutritional status. Our model shows that plants favor interaction with growth hormone producers under rich nutrient conditions but favor nutrient solubilizers under poor conditions. We also performed several comparisons among the different genera, highlighting interesting ecological interactions and limitations. Our model could be used to direct plant growth-promoting bacteria bioprospection and metagenomic sampling.

Diversity of plant growth-promoting bacteria associated with sugarcane

“…Indirectly, this genus produces antagonistic compounds for pathogens, such as hydrolytic enzymes, and antibiotics (da Costa et al, 2014).…”

Metabolic diversity of the emerging pathogenic lineages of Klebsiella pneumoniae

“…Further evidence is provided by the fact that Klebsiella have the unique property to use sucrose in its five isomers (Thompson et al ., ) and that Klebsiella strains are selected in tannic acid‐rich environments (Tahmourespour et al ., ). The presence of Klebsiella is well documented in the rhizosphere (Da Costa et al ., ) and in numerous plants, including vegetables (Falomir et al ., ), raising the possibility that people could get colonized and infected through the consumption of contaminated vegetables.…”

Parasites and competitors suppress bacterial pathogen synergistically due to evolutionary trade-offs

“…In support for this, we found that phage selection increased pathogen susceptibility to the antibiotics produced by B. amyloliquefaciens T-5-GFP ancestral bacteria. Phages often target the receptors in LPS (lipopolysaccharides) (Tamaki et al 1971;da Costa et al 2014), which is also the target of B. amyloliquefaciens produced lipopeptides (Sequeira and Graham 1977). Therefore, it is possible that phage-mediated changes in R. solanacearum LPS also affected its susceptibility to B. amyloliquefaciens antibiotics.…”