Location: Plant, Soil and Nutrition ResearchTitle: Genetic reduction of antinutrients in common bean (Phaseolus vulgaris L.) seed, increases nutrients and in vitro iron bioavailability without depressing main agronomical traits) Author
Submitted to: Field Crops Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/23/2012
Publication Date: 2/2/2013
Citation: Campion, B., Glahn, R.P., Tava, A., Perrone, D., Doria, E., Sparvoli, F. 2013. Genetic reduction of antinutrients in common bean (Phaseolus vulgaris L.) seed, increases nutrients and in vitro iron bioavailability without depressing main agronomical traits. Field Crops Research. 141:27-37. Interpretive Summary: When beans are consumed, some components lead to antinutritional effects such as reduced iron and zinc absorption, low protein digestibility and high toxicity at the intestinal level. One cause of iron deficiency is poor absorption from cereal and legume-based diets which are high in phytic acid. In the fight against iron malnutrition, the approach lies in increasing the iron content in the diet or in the seeds or improving absorption by decreasing the presence of phytic acid, polyphenols and tannins and lectins in staple crops. Using selective breeding, new bean lines were developed to improve grain nutritional characteristics, mainly to increase iron/zinc bioavailability/absorption and protein absorption and to not affect field performance (ie. lower seed viability, reduced plant growth rate and grain yield). In this study, the authors report success improving the nutritional quality of beans without negative effect on field performance.
Technical Abstract: In common bean, lectins, phytic acid, polyphenols and tannins exert major antinutritional effects when grains are consumed as a staple food. Reduced iron and zinc absorption, low protein digestibility and high toxicity at the intestinal level are the causes of their antinutritional effect. To improve grain nutritional characteristics, the “low phytic acid” (lpa) trait discovered recently in the bean mutant lpa-280-10, was introgressed into different lectin-free (lf) lines, a few of which were white seeded. The “white seed coat” (wsc) trait is correlated with a reduced amount of tannins and polyphenols in bean seed, and thus higher Fe bioavailability. Lf+lpa bean lines producing coloured and white seeds, were developed. Three of these lines were submitted to a first field performance test carried out in two Italian locations, and two of them to biochemical analyses aimed to evaluate fourteen nutritional parameters. Seedling emergence and grain yield of lf+lpa beans were statistically comparable to those of wild type cultivars, confirming the absence of major agronomic defects associated to the lpa trait. The presence of the three genetic traits lf, lpa and wsc in the same genetic background leads to a significant increase of the content of important nutrients such as crude proteins, total zinc, free phosphorus, and, in part, total iron. Iron bioavailability (as measured in vitro via a Caco-2 cell model) in lf+lpa brown and black seeds, was not significantly different from that surveyed in the wild type coloured parents, while, it was on average twelve times higher in lf+lpa white bean seeds. Up to now, the white seeded lf+lpa beans seem thus to be the only materials having really improved nutritional qualities.