Dietary Bean Consumption and Human Health

Fine mapping of the unique Ur-11 gene conferring broad resistance to the rust pathogen of common bean

KEY MESSAGE

Fine mapping positioned the Ur-11 rust resistance gene in common bean to a narrow 9 kb genomic region and enabled the development of a KASP marker tightly linked to Ur-11 for use in gene pyramiding to achieve durable rust resistance. The extensive virulence diversity of the fungal pathogen Uromyces appendiculatus threatens common bean (Phaseolus vulgaris) production. The Ur-11 gene present in the Guatemalan common bean accession PI 181996 conferred resistance to 89 of 90 virulent races of U. appendiculatus. We describe here the fine mapping of Ur-11 and the development and validation of a DNA marker tightly linked to Ur-11. An F2 population from the cross between the susceptible Pinto 114 with the resistant PI 181996 was inoculated with four races of U. appendiculatus. This study established that the rust resistance in PI 181996 was conferred by Ur-11. We then fine mapped Ur-11 using F2 plants and F2:3 families, high-throughput SNP genotyping, SSRs and KASPs marker development, whole-genome sequencing, and local haplotype analysis. Ur-11 was positioned in a narrow 9.01 Kb genomic region on chromosome Pv11 flanked by KASP markers SS322 and SS375. This genomic region included a candidate gene encoding a nucleotide-binding site and leucine rich-repeat domain with pathogen resistance functions. The validation of the SS322 KASP marker was performed on a panel of 206 diverse common bean cultivars that were inoculated with four races of U. appendiculatus. The SS322 marker was 97.5% accurate in identifying the presence of Ur-11 in common bean plants. These results suggest that S322 will be a highly effective molecular marker for the development of common bean cultivars with Ur-11 alone and combining Ur-11 with other rust resistance genes that would confer broad and durable resistance to the hypervirulent bean rust pathogen.

Prebiotic Potential of Dietary Beans and Pulses and Their Resistant Starch for Aging-Associated Gut and Metabolic Health

Dietary pulses, including dry beans, lentils, chickpeas, and dry peas, have the highest proportion of fiber among different legume cultivars and are inexpensive, easily accessible, and have a long shelf-life. The inclusion of pulses in regular dietary patterns is an easy and effective solution for achieving recommended fiber intake and maintaining a healthier gut and overall health. Dietary pulses-derived resistant starch (RS) is a relatively less explored prebiotic ingredient. Several in vitro and preclinical studies have elucidated the crucial role of RS in fostering and shaping the gut microbiota composition towards homeostasis thereby improving host metabolic health. However, in humans and aged animal models, the effect of only the cereals and tubers derived RS has been studied. In this context, this review collates literature pertaining to the beneficial effects of dietary pulses and their RS on gut microbiome-metabolome signatures in preclinical and clinical studies while contemplating their potential and prospects for better aging-associated gut health. In a nutshell, the incorporation of dietary pulses and their RS in diet fosters the growth of beneficial gut bacteria and significantly enhances the production of short-chain fatty acids in the colon.

Phenolic Composition and α-Glucosidase Inhibition of Leaves from Chilean Bean Landraces

The MeOH:H₂O (7:3) extracts of leaves from Chilean bean landraces were assessed for total phenolic (TP), total flavonoid (TF), total proanthocyanidin (TPA) content, antioxidant capacity (ORAC, FRAP, TEAC, CUPRAC, DPPH) and the inhibition of enzymes associated with metabolic syndrome (α-glucosidase, α-amylase, pancreatic lipase). The chemical profiles were analyzed by HPLC-DAD. Higher antioxidant activity in the ORAC and CUPRAC assay was found for the landrace Coscorrón, and the best effect in the TEAC for Sapito, respectively. The main phenolics were flavonol glycosides and caffeic acid derivatives. The extracts presented strong activity against α-glucosidase, but were inactive towards α-amylase and pancreatic lipase. The leaf extract from the Sapito landrace was fractionated to isolate the main α-glucosidase inhibitors, leading to caffeoylmalic acid with an IC₅₀ of 0.21 μg/mL. The HPLC fingerprints of the leaves differentiate three groups of chemical profiles, according to the main phenolic content. A significant correlation was found between the α-glucosidase inhibition, the content of caffeoylmalic acid (r = -0.979) and kaempferol 3-O-β-D-glucoside (r = 0.942) in the extracts. The presence of α-glucosidase inhibitors in the leaves of Chilean beans support their potential as a source of bioactive compounds.

Towards More Sustainable Diets-Attitudes, Opportunities and Barriers to Fostering Pulse Consumption in Polish Cities

Despite the evidence-based health benefits of pulses and their significant role in sustainable diets, consumption remains at a very low level in highly developed countries. In an attempt to fill in the knowledge gaps on factors influencing this phenomenon, a study aimed at identifying attitudes, incentives and barriers to pulse consumption was carried out in a sample of 1027 Polish urban employees aged 25-40 years. The sample (quota type) was representative in terms of age and gender. Exploratory classifications using Kohonen neural networks were performed to define profiles of participants for each analysed issue. Pearson's chi-square analysis was used to check whether the profiles depended on socio-demographic characteristics of the respondents. The results suggest that very low pulse consumption is a result of lack of habits, discomfort after eating and long preparation time. Pulses were recognized as a good source of protein (72% of the sample), especially among women (81%). Only 43% of the sample saw pulses as a substitute for meat. The majority of consumers pictured pulses as a tasty and healthy food, although they were not sure if this is true for small children. Women recognised pulses as a more environmentally friendly food but this knowledge would not impact their intake. Profiles of respondents with positive attitudes towards increased pulse consumption were identified, constituting 39% of the sample. These consumers could eat more if they were encouraged to do so. This shows that programmes aimed at fostering greater pulse consumption are crucial to activate a change towards more sustainable diets. At the same time, simple and clear guidelines should be developed to overcome the unjustified stereotypes about pulses. These would support consumers to make healthier and more sustainable choices and help professionals carry out effective promotion and education activities.