| Species name: Cultivated Sunflower(Helianthus annuus L.)|
Cultivated sunflower is a globally important oilseed crop, and also an important source of confectionery seeds and ornamental flowers. Domesticated by Native Americans from wild, common sunflower (also H. annuus) ca. 4000 years ago (Crites 1993), cultivated sunflower is the only major food crop that is native to temperate North America (Harter et al. 2004). Nuclear and chloroplast DNA evidence indicate that sunflower is likely the product of a single origin of domestication (Harter et al. 2004; Wills and Burke 2006; Blackman et al. 2011), and studies of molecular genetic variation indicate that cultivated sunflower harbors roughly two-thirds of the total genetic diversity present in wild sunflower (Burke et al 2005; Chapman et al. 2008; Cheres and Knapp 1998; Fusari et al. 2008; Liu and Burke 2006; Mandel et al. 2011).
Despite being considered members of the same species, cultivated and common sunflower exhibit a number of major morphological differences. For example, common sunflower typically exhibits a highly branched growth form with many, small flowering heads and relatively small achenes (i.e., single seeded fruits) that are released upon ripening. The typical cultivated sunflower, however, is unbranched, produces a single large flowering head, and large achenes which are retained in the head until harvest. Cultivated and wild sunflower are reproductively compatible and studies have shown that when they come into contact and flower coincidentally, common and cultivated sunflower hybridize readily (Arias and Rieseberg 1994; Whitton et al. 1997; Linder et al. 1998).
Following its domestication, sunflower was used by Native Americans as an important source of edible seeds as well as for a variety non-food applications (e.g., as a source of dye for textiles and for ceremonial purposes) (Heiser et al 1969; Soleri and Cleveland 1993). In the early 16th century, sunflower was brought to Europe by Spanish explorers where it was initially grown as an ornamental (Putt 1997). During the 18th century and beyond, sunflower was increasingly used as a source of vegetable oil, and breeding efforts focused primarily on improving oil yield. This was particularly true in the late 19th century through the mid-20th century in Eastern Europe, where sunflower was grown on a large scale (Pustovoit 1964).
The germplasm that formed the basis of the modern oilseed gene pool was ultimately brought back to North America, and the first commercial high-oil sunflower lines were grown in the United States in the 1960s (Putt 1997). In the 1970s, attention turned to hybrid production and the development of the necessary inbred lines, primarily due to the higher yields and greater disease resistance afforded by hybrids (Robertson and Burns 1975). While confectionery lines were being developed at the same time, oilseed production soon surpassed non-oilseed production, and breeders increasingly shifted their focus to the continued development of improved oilseed cultivars. The oil derived from cultivated sunflower is light in taste, consists of monounsaturated and polyunsaturated fats with low saturated fat levels, and contains high amounts of Vitamin E (Allman-Farinelli et al. 2005).
- Numerous genetic linkage maps based on thousands of genetic markers and a variety of crosses, many of which are available online here;
- Permanent (RIL) mapping populations, including populations derived from oilseed x confectionery (Tang et al. 2002), oilseed x landrace (Barb et al. unpublished), and oilseed x wild (Baack et al. 2008) crosses.
- H. annuus ESTs (over 130,000 Sanger reads) available on GenBank, available online here;
- Sunflower cDNA clones (ca. 148k available for ordering), details available online here;
- Sunflower BAC library with 8x estimated coverage available for ordering, details available online here;
- Complete genome sequence of an oilseed line is currently being produced, details available online here;
- Germplasm (2847 total H. annuus accessions) available from the USDA Germplasm Resources Information Network, details available online here;
- Phenotypic information for a variety of accessions/populations is available from ARS-GRIN (above) or MorphoDB.
- Additional assembly information: download here
| Images of Helianthus annuus|
| Figure 1: Helianthus annuus By Nolan Kane||
| Figure 2: Helianthus annuus By Nolan Kane||
| Figure 3: Helianthus annuus flowers||
| Figure 4: Helianthus annuus By Nolan Kane||
| Figure 5: From Wikipedia||
| CGP Activities|
The CGP has developed extensive genomic resources and data for cultivated sunflower including the generation of numerous genetic markers, linkage and QTL maps, interspecific comparative maps, expressed sequence tags (ESTs), and a gene space sequence (i.e., sequence of the low copy, gene-rich fraction of the genome). The CGP has also been heavily involved in the generation of sunflower permanent mapping populations including the three RIL populations mentioned above, as well as an association mapping panel. These resources have been utilized by a wide range of researchers.
The CGP has also developed and is utilizing a 2.6 million feature Affymetrix chip based on 87,000 unigenes from seven Helianthus spp. The aforementioned oil x confectionery RIL mapping population has being interrogated using this array, and we are currently in the process of generating a high-density transcript map of the cultivated sunflower genome using these data. In addition to being an invaluable resource for the sunflower community, this high-density map will assist in the sunflower genome assembly. The CGP has also spearheaded the development of a NimbleGen expression array with over 200,000 features for investigating patterns of gene expression in sunflower (Lai et al. 2012.) Lastly, we have sequenced ca. 75 EST libraries for H. annuus using next generation approaches (454 and Illumina), which will be made public soon.
Finally, the CGP has been analyzing candidate genes underlying key traits for sunflower utilizing a variety of approaches, including allele re-sequencing, genetic mapping, association analyses, and expression studies. The goal of these studies is to correlate sequence and/or structural variation with agronomically-important phenotypes as well as to establish functional orthology with important genes from other crops and model systems.
(bold denotes CGP authorship)
Allman-Farinelli MA, Gomes K, Favaloro EJ, Petocz P (2005) A Diet Rich in High-Oleic-Acid Sunflower Oil Favorably Alters Low-Density Lipoprotein Cholesterol, Triglycerides, and Factor VII Coagulant Activity. Journal of the American Dietetic Association 105:1071-1079
Arias DM, Rieseberg LH (1994) Gene flow between cultivated and wild sunflowers. Theoretical and Applied Genetics 89:655-660
Baack EJ, Sapir Y, Chapman MA, Burke JM, Rieseberg LH (2008) Selection on domestication traits and QTLs in crop-wild sunflower hybrids. Molecular Ecology 17:666-677
Berry ST, Leon AJ, Hanfrey CC, Challis P, Burkholz A, Barnes SR, Rufener GK, Lee M, Caligari PDS (1995) Molecular marker analysis of Helianthus annuus L.2. Construction of an RFLP linkage map for cultivated sunflower. Theoretical and Applied Genetics 91:195-199.
Blackman BK, Scascitelli M, Kane NC, Luton HH, Rasmussen DA, Bye RA, Lentz DL, Rieseberg LH. 2011. Sunflower domestication alleles support single domestication center in eastern North America. Proceedings of the National Academy of Sciences, 108:14360–14365.
Burke JM, Tang S, Knapp SJ, Rieseberg LH (2002) Genetic analysis of sunflower domestication. Genetics 161:1257-1267.
Burke JM, Knapp SJ, Rieseberg LH (2005) Genetic consequences of selection during the evolution of cultivated sunflower. Genetics 171:1933-1940
Chapman MA, Pashley CH, Wenzler J, Hvala J, Tang S, Knapp SJ, Burke JM (2008) A genomic scan for selection reveals candidates for genes involved in the evolution of cultivated sunflower (Helianthus annuus L.). Plant Cell 20:2931-2945
Cheres MT, Knapp SJ (1998) Ancestral origins and genetic diversity of cultivated sunflower: coancestry analysis of public germplasm. Crop Science 38:1476-1482
Crites GD (1993) Domesticated Sunflower in Fifth Millennium B.P. Temporal Context: New Evidence From Middle Tennessee. American Antiquity 58:146-148
Gedil, MA, Wye C, Berry S, Segers B, Peleman J, Jones R, Leon A, Slabaugh MB, Knapp SJ (2001) An integrated restriction fragment length polymorphism - amplified fragment length polymorphism linkage map for cultivated sunflower. Genome 44:213-221.
Gentzbittel L, Vear F, Zhang YX, Berville A, Nicolas P (1995) Development of a consensus linkage RFLP map of cultivated sunflower (Helianthus annuus L.) Theoretical and Applied Genetics 90:1079-1086.
Heesacker A, Kishore VK, Gao WX, Tang SX, Kolkman JM, Gingle A, Matvienko M, Kozik A, Michelmore RM, Lai Z, Rieseberg LH, Knapp SJ (2008) SSRs and INDELs mined from the sunflower EST database: abundance, polymorphisms, and cross-taxa utility. Theoretical and Applied Genetics 117:1021-1029.
Heiser CB, Smith DM, Clevenger S, Martin WC (1969) The North American sunflowers (Helianthus). Memoirs of the Torrey Botanical Club 22:1-218
Jan CC, Vick BA, Miller JF, Kahler AL, Butler ET (1998) Construction of an RFLP linkage map for cultivated sunflower. Theoretical and Applied Genetics 96:15-22.
Kane NC, Gill N, King MG, Bowers JE, Berges H, Gouzy J, Bachlava E, Langlade NM, Lai Z, Stewart M, Burke JM, Vincourt P, Knapp SJ, Rieseberg LH (2011) Progress towards a reference genome for sunflower. Botany 89:429–437.
Lai Z, Livingstone K, Zou Y, Church SA, Knapp SJ, Andrews J, Rieseberg LH (2005) Identification and mapping of SNPs and candidate genes in sunflower: towards a functional map. Theoretical and Applied Genetics 111:1532-1544.
Lai, Z., N.C. Kane, A. Kozik, K.A. Hodgins, K.M. Dlugosch, M.S. Barker, M. Matvienko, Q. Yu, K.G. Turner, S.A. Pearl, G.D.M. Bell, Y. Zou, C. Grassa, A. Guggisberg, K.L. Adams, J.V. Anderson, D.P. Horvath, R.V. Kesseli, J.M. Burke, R.W. Michelmore, and L.H. Rieseberg. 2012. Genomics of Compositae weeds: EST libraries, microarrays, and evidence of introgression. American Journal of Botany, in press.
Linder CR, Taha I, Seiler GJ, Snow AA, Rieseberg LH. 1998. Long-term introgression of crop genes into wild sunflower populations. Theoretical and Applied Genetics 96:339-347.
Mandel JR, Dechaine JM, Marek LF, Burke JM (2011) Genetic diversity and population structure in cultivated sunflower and a comparison to its wild progenitor, Helianthus annuus L. Theoretical and Applied Genetics, DOI 10.1007/s00122-011-1619-3
Pustovoit VS (1964) Conclusions of work on the selection and seed production of sunflowers (in Russian). Agrobiology, 5:662-697
Putt ED (1997) Early history of sunflower. In: Scheiter AA (ed) Sunflower Production and Technology. American Society Agronomy, Madison, WI, pp 1-19
Robertson JA, Burns EE (1975) Use of sunflower seed in food products. Critical Reviews Food Science 6:201-240
Soleri D, Cleveland D (1993) Hopi crop diversity and change. Journal of Ethnobiology 13:203-231
Tang S, Yu JK, Slabaugh MB, Shintani DK, Knapp SJ (2002) Simple sequence repeat map of the sunflower genome. Theoretical and Applied Genetics 105:1124-1136
Whitton J, Wolf DE, Arias DM, Snow AA, Rieseberg LH (1997) The persistence of cultivar alleles in wild populations of sunflowers five generations after hybridization. Theoretical and Applied Genetics 95:33-40
Wills DM, Burke JM (2006) Chloroplast DNA variation confirms a single origin of domesticated sunflower (Helianthus annuus L.) Journal of Heredity 97:403-408.
Yu JK, Tang S, Slabaugh MB, Heesacker A, Cole G, Herring M, Soper J, Han F, Chu WC, Webb DM, Thompson L, Edwards KJ, Berry S, Leon AJ, Grondona M, Olungu C, Maes N, Knapp SJ (2003) Towards a saturated molecular genetic linkage map for cultivated sunflower. Crop Science 43:367-387