Strategies and advances to identify candidate genes controlling low vicine-convicine in faba vean (Vicia faba L.)

Abstract

Trabajo presentado en el Second International Legume Society Conference "Legumes for a sustainable world" (ILS2), celebrado en Tróia (Portugal) del 11 al 14 de octubre de 2016.Vicine and convicine (v-c), limit the use of faba bean as food and feed. A single gene vc-, responsible for a 10-20 fold reduction in v-c, 10 cM apart from the white hilum has been describ ed (Duc et al. 1989; 2004). Khazaei et al. (2015), reported a QTL for v-c content on chromosome I (Chr I) and although several closer markers were identified (Gutierrez et al. 2006) no candidate genes are so far available. The identification of suitable candidate genes is limited for the lack of knowledge of the pathway for the v-c biosynthesis and the large faba bean genome size (~13 Gbp). In an attempt to determine which enzymes or transcriptional regulat ors could be encoded by the vc-gene, we are applying a combination of genetic linkage and comparative genomic approaches. To facilitate high-throughput genome profiling DarTSeq (Kilian et al. 2012) has been applied in a RIL population from the cross Vf6 (high v-c) x vc-(low v-c) generating more than 10.000 markers. For the assignment of the linkage group to specific chromosomes, 58 EST anchor marker from the reference consensus map (Satovic et al. 2013) were assayed and 14 of them could be mapped. On the other hand, 37 SNPs, from the KASPar assay platform (Semagn et al. 2014) belonging to Chr I, were genotyped and 9 of them, resulted polymorphic. The moderate conservation of the faba bean Chr 1 with the Medicago Chr 2 confined the target region between Medtr2g005900 and Medtr2g026550. To fine mapping the v-c position, primers for 61 new candidates were designed using both the Medicago (29) and the faba bean (32) transcriptome sequences (Ocaña et al. 2015) and 12 genes could be mapped. The forthcoming linkage analysis may provide potential candidate genes for the target trait.N