Common bean (Phaseolus vulgaris L.) with increased cysteine and methionine concentration

Authors: VISCARRA-TORRICO, ROSA CECILIA - Agriculture And Agri-Food Canada; PAJAK, AGA - Agriculture And Agri-Food Canada; GARZON, ALVARO SOLER - Washington State University; ZHANG, BAILING - Agriculture And Agri-Food Canada; PANDURANGAN, SUDHAKAR - Agriculture And Agri-Food Canada; DIAPARI, MARWAN - Agriculture And Agri-Food Canada; Song, Qijian; CONNER, ROBERT - Agriculture And Agri-Food Canada; HOUSE, JAMES - University Of Manitoba; Miklas, Phillip - Phil; HOU, ANFU - Agriculture And Agri-Food Canada; MARSOLAIS, FREDERIC - Agriculture And Agri-Food Canada

Submitted to: Legume Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2021
Publication Date: 6/17/2021
Citation: Viscarra-Torrico, R., Pajak, A., Garzon, A., Zhang, B., Pandurangan, S., Diapari, M., Song, Q., Conner, R.L., House, J.D., Miklas, P.N., Hou, A., Marsolais, F. 2021. Common bean (Phaseolus vulgaris L.) with increased cysteine and methionine concentration. Legume Science. https://doi.org/10.1002/leg3.103.
DOI: https://doi.org/10.1002/leg3.103

Interpretive Summary: Common bean is primarily a protein source in human diets. Like other pulses, the quality of its protein, as defined by the balanced composition of nutritionally essential amino acids, is limited first and foremost by the levels of sulfur amino acids, methionine and cysteine. Previous studies showed that approximately half of the total protein in cultivated varieties of common bean was accounted by the globulin seed storage protein phaseolin which is devoid of cysteine and has low methionine. Deficiency in phaseolin and lectins results in a significant increase in sulfur amino acid concentration in breeding lines through proteomic rebalance in common bean plants. In this study, we crossed the line deficient in phaseolin and major lectins with the commercial cultivar and recovered two lines with increased cysteine and methionine concentration and with adaptation to growing conditions in Manitoba, Canada. We also identified and validated three DNA markers that can track phaseolin deficiency in the breeding lines. The lines generated in this study can be used as parents to improve common bean protein nutrition by breeders and geneticists working in private and public sectors. The markers are useful to validate genetic material for phaseolin deficiency, to track the introgression of the trait across different genetic backgrounds and environments and to accelerate high sulfur amino acid breeding.

Technical Abstract: In common bean (Phaseolus vulgaris L.), seed storage protein deficiency is associated with increased total cysteine and methionine concentration. The goal of this study was to generate germplasm lines that combine this characteristic with adaptation to growing conditions in Manitoba, Canada. A recombinant inbred line population was developed by crossing the storage protein deficient genotype, SMARC1N-PN1 with the cultivar Morden003. Two lines, 2-37 and 3-84, with a stable protein profile over two years at two locations were identified. Like SMARC1N-PN1, both of them had a significantly higher cysteine concentration than Morden003, by approximately 35%. Methionine levels were elevated by approximately 15%, while tryptophan levels were also increased by approximately 30%. Line 2-37 had a significant increase in protein quality, as measured by in vitro protein digestibility corrected amino acid score, by approximately 40%, as compared with Morden003. The increased protein quality for this line is attributable to higher levels of total cysteine and methionine, while having an overall reduction in crude protein concentration. Line 2-37 had a similar seed yield as SMARC1N-PN1, with a maturity comparable to Morden003. The results of high-density single nucleotide polymorphism (SNP) genotyping and quantitative trait locus analysis of recombinant inbred lines indicated that variation in cysteine concentration was determined by the phaseolin locus, while variation in methionine concentration was determined by both the phaseolin and lectin loci. SNP markers that track the introgression of phaseolin and lectin deficiency into the Morden003 background were identified and validated.