Using NMR-based metabolomics to evaluate postprandial urinary responses following consumption of minimally processed wheat bran or wheat aleurone by men and women

Wheat bran, and especially wheat aleurone fraction, are concentrated sources of a wide range of components which may contribute to the health benefits associated with higher consumption of whole-grain foods. This study used NMR metabolomics to evaluate urine samples from baseline at one and two hours postprandially, following the consumption of minimally processed bran, aleurone or control by 14 participants (7 Females; 7 Males) in a randomized crossover trial. The methodology discriminated between the urinary responses of control, and bran and aleurone, but not between the two fractions. Compared to control, consumption of aleurone or bran led to significantly and substantially higher urinary concentrations of lactate, alanine, N-acetylaspartate acid and N-acetylaspartylglutamate and significantly and substantially lower urinary betaine concentrations at one and two hours postprandially. There were sex related differences in urinary metabolite profiles with generally higher hippurate and citrate and lower betaine in females compared to males. Overall, this postprandial study suggests that acute consumption of bran or aleurone is associated with a number of physiological effects that may impact on energy metabolism and which are consistent with longer term human and animal metabolomic studies that used whole-grain wheat diets or wheat fractions.

Wheat seed embryo excision enables the creation of axenic seedlings and Koch’s postulates testing of putative bacterial endophytes

Early establishment of endophytes can play a role in pathogen suppression and improve seedling development. One route for establishment of endophytes in seedlings is transmission of bacteria from the parent plant to the seedling via the seed. In wheat seeds, it is not clear whether this transmission route exists, and the identities and location of bacteria within wheat seeds are unknown. We identified bacteria in the wheat (Triticum aestivum) cv. Hereward seed environment using embryo excision to determine the location of the bacterial load. Axenic wheat seedlings obtained with this method were subsequently used to screen a putative endophyte bacterial isolate library for endophytic competency. This absence of bacteria recovered from seeds indicated low bacterial abundance and/or the presence of inhibitors. Diversity of readily culturable bacteria in seeds was low with 8 genera identified, dominated by Erwinia and Paenibacillus. We propose that anatomical restrictions in wheat limit embryo associated vertical transmission, and that bacterial load is carried in the seed coat, crease tissue and endosperm. This finding facilitates the creation of axenic wheat plants to test competency of putative endophytes and also provides a platform for endophyte competition, plant growth, and gene expression studies without an indigenous bacterial background.

Effects of rain shelter or simulated rain during grain filling and maturation on subsequent wheat grain quality in the UK

The effects of simulated additional rain (ear wetting, 25 mm) or of rain shelter imposed at different periods after anthesis on grain quality at maturity and the dynamics of grain filling and desiccation were investigated in UK field-grown crops of wheat (Triticum aestivum L., cvar Tybalt) in 2011 and in 2012 when June–August rainfall was 255.0 and 214.6 mm, respectively, and above the decadal mean (157.4 mm). Grain filling and desiccation were quantified well by broken-stick regressions and Gompertz curves, respectively. Rain shelter for 56 (2011) or 70 d (2012) after anthesis, and to a lesser extent during late maturation only, resulted in more rapid desiccation and hence progress to harvest maturity whereas ear wetting had negligible effects, even when applied four times. Grain-filling duration was also affected as above in 2011, but with no significant effect in 2012. In both years, there were strong positive associations between final grain dry weight and duration of filling. The treatments affected all grain quality traits in 2011: nitrogen (N) and sulphur (S) concentrations, N:S ratio, sodium dodecyl sulphate (SDS) sedimentation volume, Hagberg Falling Number (HFN), and the incidence of blackpoint. Only N concentration and blackpoint were affected significantly by treatments in 2012. Rain shelter throughout grain filling reduced N concentration, whereas rain shelter reduced the incidence of blackpoint and ear wetting increased it. In 2011, rain shelter throughout reduced S concentration, increased N:S ratio and reduced SDS. Treatment effects on HFN were not consistent within or between years. Nevertheless, a comparison between the extreme treatment means in 2012 indicated damage from late rain combined with ear wetting resulted in a reduction of c. 0.7 s in HFN/mm August rainfall, whilst that between samples taken immediately after ear wetting at harvest maturity or 7 d later suggested recovery from damage to HFN upon re-drying in planta. Hence, the incidence of blackpoint was the only grain quality trait affected consistently by the diverse treatments. The remaining aspects of grain quality were comparatively resilient to rain incident upon developing and maturing ears of cvar Tybalt. No consistent temporal patterns of sensitivity to shelter or ear wetting were detected for any aspect of grain quality.