Browsing by Subject "convicine"

Faba bean (Vicia faba L.) is an annual herbaceous cool-season food legume widely cultivated worldwide, especially for its high seed protein content. However, its major limitation in being used as food and feed, is the presence of antinutritional factors in its seeds, especially vicine and convicine (VC), two related compounds, which may be harmful to livestock and G6PD-deficient humans. To remove VC, the most sustainable method is breeding for low-VC faba bean cultivars. To improve the efficiency and speed of breeding programs, breeders use marker-assisted selection (MAS). The identification of genes responsible for VC content allows the development of reliable DNA markers and a better understanding of the molecular basis of this trait. The major-effect QTL controlling VC content named “VC1”, was identified in faba bean chromosome 1, and a few minor-effect QTLs were detected in previous studies. Hence, a total of 165 RILs from the cross Mélodie/2 (low-VC) x ILB 938/2 (high-VC) were genotyped and evaluated for VC content. Composite interval mapping was run on R/qtl software with accurate phenotypic data associated with a high-density SNP-based genetic map. Results revealed two minor-effect QTLs in addition to VC1. One was on chromosome 4 and had about 15% effect on convicine content. The other was on chromosome 5 and had 15% effect on vicine and total VC content. This research also reports candidate genes for the newly detected minor-effect QTLs through comparative genomics with the Medicago truncatula genome. Hypotheses were proposed on the role of these candidate genes on the VC biosynthetic pathway or transportation into the embryo beans for further testing.

Faba bean (Vicia faba L.) also known as broad bean is an ancient pulse, grown since Neolithic times. It is an excellent source of protein, energy and fibre to humans and animals. Recently in Finland, faba bean has featured heavily in meat replacements, meant for vegan consumers. Faba bean can also be grown further north, than soybean (Glycine max (L.) Merr.), making it a possible domestic plant protein source for Finns. The problem with faba bean is that the beans contain various anti-nutritional compounds. The major ones are vicine and convicine (v-c), located in the cotyledons of the beans, which means that dehulling the seeds does not remove them. V-c can cause favism in humans with G6PD gene mutation this is a disease where red blood cells are destroyed, in worst cases resulting in blood transfusions and death. V-c is also an anti-feedant to livestock and can among other things cause increase in mortality in poultry. Normal v-c content of faba bean is around 1%. There are low v-c faba beans that contain only 5-15% of the original v-c. Markers for this trait have been found, but gene controlling for this trait is not known yet. The synthesis pathway of the v-c is not known. There is a new hypothesis by Dr Fernando Geu Flores of The University of Copenhagen, where the v-c synthesis is an off shoot of another biosynthetic pathway. An experiment was done where RNA of two populations (one low v-c and other high) were compared to each other. The samples were taken during the seed filling period, which is thought to be when v-c is synthesized. Kernel, testa, pod and leaf tissues were collected and RNA of those extracted. Only kernel and testa samples were sequenced. This thesis focuses on the testa results. Results showed differences between the populations. Considering the new hypothesis, the results showed some differences in the beginning of the suspected pathway, with the high v-c population having a 4.97 fold increase compared to the low v-c population. Other differences were also noted, which may cast light on other steps in the pathway.