Polychlorinated biphenyls modify root exudation pattern to accommodate degrading bacteria, showing strain and functional trait specificity.

Introduction: The importance of plant rhizodeposition to sustain microbial growth and induce xenobiotic degradation in polluted environments is increasingly recognized.

Methods: Here the "cry-for-help" hypothesis, consisting in root chemistry remodeling upon stress, was investigated in the presence of polychlorinated biphenyls (PCBs), highly recalcitrant and phytotoxic compounds, highlighting its role in reshaping the nutritional and signaling features of the root niche to accommodate PCB-degrading microorganisms.

Results: exposure to 70 µM PCB-18 triggered plant-detrimental effects, stress-related traits, and PCB-responsive gene expression, reproducing PCB phytotoxicity.

Flavonoids influence key rhizocompetence traits for early root colonization and PCB degradation potential of LB400.

Introduction: Flavonoids are among the main plant root exudation components, and, in addition to their role in symbiosis, they can broadly affect the functionality of plant-associated microbes: in polluted environments, for instance, flavonoids can induce the expression of the enzymatic degradative machinery to clean-up soils from xenobiotics like polychlorinated biphenyls (PCBs). However, their involvement in root community recruitment and assembly involving non-symbiotic beneficial interactions remains understudied and may be crucial to sustain the holobiont fitness under PCB stress.

Methods: By using a set of model pure flavonoid molecules and a natural blend of root exudates (REs) with altered flavonoid composition produced by mutant lines affected in flavonoid biosynthesis and abundance (null mutant , flavonoid aglycones hyperproducer , and flavonoid conjugates hyperaccumulator ), we investigated flavonoid contribution in stimulating rhizocompetence traits and the catabolic potential of the model bacterial strain for PCB degradation LB400.

Flavonoids Are Intra- and Inter-Kingdom Modulator Signals.

Flavonoids are a broad class of secondary metabolites with multifaceted functionalities for plant homeostasis and are involved in facing both biotic and abiotic stresses to sustain plant growth and health. Furthermore, they were discovered as mediators of plant networking with the surrounding environment, showing a surprising ability to perform as signaling compounds for a multitrophic inter-kingdom level of communication that influences the plant host at the phytobiome scale. Flavonoids orchestrate plant-neighboring plant allelopathic interactions, recruit beneficial bacteria and mycorrhizal fungi, counteract pathogen outbreak, influence soil microbiome and affect plant physiology to improve its resilience to fluctuating environmental conditions.

'Cry-for-help' in contaminated soil: a dialogue among plants and soil microbiome to survive in hostile conditions.

An open question in environmental ecology regards the mechanisms triggered by root chemistry to drive the assembly and functionality of a beneficial microbiome to rapidly adapt to stress conditions. This phenomenon, originally described in plant defence against pathogens and predators, is encompassed in the 'cry-for-help' hypothesis. Evidence suggests that this mechanism may be part of the adaptation strategy to ensure the holobiont fitness in polluted environments.

Lignin-Based Pesticide Delivery System.

The potential of lignosulfonates as widely underutilized byproducts of the pulp and paper industry for the synthesis of a biodegradable pesticide carrier system was assessed in this study. Design of experiment software MODDE Pro was for the first time applied to optimize lignosulfonate granule production using laccase as a biocatalyst. Enzymatic cross-linking was monitored using size exclusion chromatography coupled online to multiangle laser light scattering, viscosity measurement, and enzyme activity.