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Background: Dietary assessment in research and clinical settings is largely reliant on self-reported questionnaires. It is acknowledged that these are subject to measurement error and biases and that objective approaches would be beneficial. Dietary biomarkers have been purported as a complimentary approach to improve accuracy of dietary assessment. Tentative biomarkers have been identified for many individual fruit and vegetables (FV) but an objective total FV intake assessment tool has not been established. Objective: We aimed to derive and validate a prediction model of total FV intake (TFVpred) to inform future biomarker studies. Methods: Data from the National Diet and Nutrition Survey (NDNS) were used for this analysis. A modelling group (MG) consisting of participants aged >11 years from the NDNS years 5-6 was created (n=1746). Intake data for 96 FVs were analysed by stepwise regression to derive a model that satisfied three selection criteria: standard error of the estimate (SEE) ≤80, R2>0.7, and ≤10 predictors. The TFVpred model was validated using comparative data from a validation group (VG) created from the NDNS years 7-8 (n=1865). Pearson’s correlation coefficients were assessed between observed and predicted values in the MG and VG. Bland-Altman plots were used to assess agreement between TFVpred estimates and total FV intake. Results: A TFVpred model, comprised of tomatoes, apples, carrots, bananas, pears, strawberries and onions, satisfied selection criteria (R2=0.761, SEE=78.81). Observed and predicted total FV intake values were positively correlated in the MG (r=0.872, P

Copyright © 2021, American Association for the Advancement of Science. Plant roots and animal guts have evolved specialized cell layers to control mineral nutrient homeostasis. These layers must tolerate the resident microbiota while keeping homeostatic integrity. Whether and how the root diffusion barriers in the endodermis, which are critical for the mineral nutrient balance of plants, coordinate with the microbiota is unknown. We demonstrate that genes controlling endodermal function in the model plant Arabidopsis thaliana contribute to the plant microbiome assembly. We characterized a regulatory mechanism of endodermal differentiation driven by the microbiota with profound effects on nutrient homeostasis. Furthermore, we demonstrate that this mechanism is linked to the microbiota's capacity to repress responses to the phytohormone abscisic acid in the root. Our findings establish the endodermis as a regulatory hub coordinating microbiota assembly and homeostatic mechanisms.