Looking Forward: Dry Bean Improvement in the Next 30 years!

Transcription

1 Looking Forward: Dry Bean Improvement in the Next 30 years! Mark Brick Department of Soil and Crop Sciences Colorado State University, Fort Collins, CO 1

2 Common Bean (Phaseolus vulgaris L.) comes in many forms. 2

3 Archeological records indicate that beans were consumed by Native Americans in Peru over 8,000 years ago. 3

4 Dietary Fiber in the Diet Physiological effects in the human alimentary canal have demonstrated positive health benefits, primarily Laxation Blood cholesterol attenuation Blood glucose attenuation Fiber is also known to play a role in reducing the incidence of disorders such as colorectal cancer, diabetes, and diverticular disease. 4

5 Beans are High in Dietary Fiber Recommended adult DF daily intake: 21 to 40 g day -1 Actual consumption = g day -1 Most countries are below this level 5

6 What is Dietary Fiber? In 1953, Eben Hipsley first used the term Dietary Fiber to describe a component of human diet: Total Dietary Fiber includes: Soluble dietary fiber (SDF) Insoluble dietary fiber (IDF) Oligosaccharides (OLI) 6

7 Objectives of the Research 1. Determine soluble and insoluble dietary fiber (TDF) and oligosacchride content in a panel of dry bean lines/cultivars. 2. Use Genome Wide Association studies to understand the genetic control of dietary fiber traits in bean. 7

8 Dietary Fiber of Germplasm Was Determined Using the Modified AOAC Sample preparation: Soak ~1 g dried bean seed in tubes containing 8 ml distilled water for 14 h Transfer tubes to autoclave and cook 65 minutes Homogenize cooked sample in tube 8

9 Enzymatic Digestion with Pancreatic α amylase and amyloglucosidase. Incubate at 37 C for 16 hours. 9

10 Filtration Captures Fiber 1. First gravimetric filtration provides high molecular weight insoluble dietary fiber (HMWIDF=IDF) 2. Second gravimetric filtration provides high molecular weight soluble dietary fiber (HMWSDF=SDF) 10

11 Fiber Residues Dried and Weighed To Calculate IDF and SDF 11

12 Variation in Dietary Fiber Content Among Cultivars 12

13 IDF and SDF Fiber Varies Among Bean Cultivars Entry % IDF % SDF % TDF Range (%) Highest PR IP ND Mean = 29.6% AC Resolute Max Lowest T Norstar BelMiNeb-RMR Mean = 23.3% Topaz AC Pintoba

14 Raffinose, Stachyose, Verbascose, and Total Oligosaccharide Content Also Varies Among Dry Bean Cultivars (n = 282) Entry % Raffinose % Stachyose % Verbascose % Total Oligos Range (%) Highest ND Centa Pupil Ind. Jamaica Red GN Star Inta Precoz Lowest Mariah NE ND T F Tukey's MSD (0.05)

15 CONCLUSIONS Beans are High in Dietary Fiber At the recommended adult DF daily intake for an average weight person: ~29 g day -1 One-half cup (125 g)cooked beans: Cultivar with 30 % DF provides ~ 11.4 g Current data base indicates 8 g. Thebeaninstitute.com 15

16 Other Pulse Crops Based on the AOAC (Brick and Thompson, 2016) IDF % Dry bean 14.2 ± 1.1 (11 to 16) Chickpeas 15.7 ± 1.7 (10 to 20) Dry Peas 16.0 ± 2.2 (12 to 22) Lentils 13.6 ± 0.6 (11 to 15) SDF % Mean ±S.E. Range 5.8 ± 1.2 (4 to 11) 3.5 ± 1.1 (2 to 6) 3.9 ± 1.0 (2 to 8) 3.2 ± 0.3 (2 to 4) Oligos % 3.1 ± 0.4 (2 to 5) 2.9 ± 0.8 (2 to 4) 4.6 ± 1.1 (3 to 6) 3.3 ± 0.6 (3 to 4) Total %

17 Genome Wide Association Studies Candidate Gene Discovery 17

18 Germplasm Evaluated 284 dry bean cultivars from the Middle American Gene Pool were grown in a field trial in Fort Collins, Colorado USA Genotyping A combination of two 6K iselect Illumina SNP chips and genotype by sequencing (GBS) data were used to genotype lines. Merged data yielded 35K potential SNPs. 18

19 Genome Wide Association Studies Assembled genome data 474 Mb (of predicted 587 Mb) 11 pseudochromosomes 98% of assembled data 27,197 genes Similar to most eukaryotes 27,082 genes in pseudochromosomes Statistical significance Top 0.1% (~15 markers) or 1% (~150) markers 19

20 Common Bean Sequencing Project: Personnel/Funding Sequencing Project Leads Scott Jackson, University of Georgia, PD Phil McClean, North Dakota State University, Co-PD Jeremy Schmutz, Hudson-Alpha, Co-PD Dan Rokshar, DOE-JGI, Co-PD Perry Cregan, USDA/Beltsville Funding USDA/AFRI: DOE/JGI: DE-AC02-05CH1123 ARRA: UC Berkeley 20

21 Genome Wide Association Studies (GWAS): Manhattan Plot Chromosomes 1 through 11 21

22 IDF SDF I+S TDF Manhattan plots, QQ plots, and the phenotypic distribution of Dietary Fiber (IDF, SDF, IDF+SDF, AND TDF). 22

23 RAF STA VER TOT Manhattan plots, QQ plots, and the phenotypic distribution of oligosaccharide content (RAFF, STACH, VERB, OLIGOS). 23

24 Insoluble and soluble dietary fiber candidate genes in the surrounding region of significant SNP markers. Pv SNP position (bp) -log 10 (p) Marker distance from candidate gene (bp) 2 26,844, Bean candidate gene IDF Phvul.002G Arabidop sis gene model AT3G Arabido psis gene symbol ATCSLD3, CSLD3,KJ K Arabidopsis annotation Cellulose synthase like 1 2,165, ,355 Phvul.001G AT5G FRA1 Fragile fiber SDF 8 7,748, , ,748, ,010 Phvul.008G Phvul.008G AT5G AT5G AGAL1, AtAGAL1 Alphagalactosida se Glycosyl hydrolase superfamily 24

25 Oligosaccharide candidate genes in the surrounding region of significant SNP markers. Pv SNP position (bp) -log 10 (p) Marker distance from candidate gene (bp) Bean candidate gene Arabid opsis gene model Arabido psis gene symbol Arabidopsis annotation 1 47,818, , ,895, , ,928, , ,758, ,620 TOTAL OLIGOs Phvul.001G Phvul.001G Phvul.001G Phvul.005G Phvul.011G AT4G AT2G AT1G AT3G AT2G AtSTS, STS AtGolS1, GolS1 UGT88A1 BGLU17 Stachyose synthase Galactinol synthase 1 Pectin lyase-like superfamily protein UDP-glucosyl transferase beta glucosidase 25

26 Conclusions We found regions on chromosomes and 8 that were associated with SDF, IDF, and TDF content. Regions on chromosome 1 and 2 were exclusively detected for IDF implying a different genetic architecture for IDF than SDF. Candidate genes were identified for all three components of Dietary Fiber in common bean. 26

27 Future Outlook With new genomic tools plant breeders should be able to alter the components of Dietary Fiber in common bean, and likely all pulse crops. We should be able to breed common bean for designer Dietary Fiber. 27

28 Thank You! 28