Electrophoretic characterization of Amaranthus L. seed proteins and ...

Botanical Journal of the Linnean Society, 2007, 155, 57–63. With 2 figuresElectrophoretic characterization of Amaranthus L. seedproteins and its systematic implicationsROCIO JUAN 1 , JULIO PASTOR 1 *, MANUEL ALAIZ 2 and JAVIER VIOQUE 21Department of Plant Biology and Ecology, University of Sevilla, 41012-Sevilla, Spain2Instituto de la Grasa (C.S.I.C), Padre García Tejero 4, 41012-Sevilla, SpainReceived March 2006; accepted for publication March 2007The seed protein profiles of 11 Amaranthus taxa (Amaranthaceae) from Spain were studied. These profileswere evaluated as a chemical character to clarify the taxonomic complexity in the genus. Tricine-sodiumdodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles of the Amaranthus seed proteins studiedshowed a range of peptides varying from 64 to 12 kDa, with a larger number of protein bands observed between25.1 and 12 kDa. For the taxonomic study, 14 bands, some of them subdivided into several isoforms, wereconsidered. The similarity analysis based on the SDS-PAGE profile is a useful character for the discrimination ofspecies in Amaranthus, except for A. cruentus and A. hypochondriacus, for which a hybrid population was found.© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 57–63.ADDITIONAL KEYWORDS: Amaranthaceae – electrophoresis – taxonomy.INTRODUCTIONAmaranthus species have different centres of domesticationand origin, being widely distributed in NorthAmerica, Central America, and the South AmericanAndes, where the greatest genetic diversity is found(Sun, Chen & Leung, 1999; Xu & Sun, 2001). It isestimated that there are 87 species of Amaranthus:17 in Europe, 14 in Australia, and 56 in America(Mujica & Jacobsen, 2003). Because of the paucity ofstudies on Amaranthus systematics, however, thenumber of species is still tentative. Some species arecosmopolitan, being both introduced and naturalizedplants, with a weed-like behaviour, such as A. retroflexus,A. hybridus, A. powellii, and A. viridis (ElAydam & Bürki, 1997; Costea, Waines & Sanders,2001b; Dehmer, 2003; Costea, Weaver & Tardif, 2004).Amongst the cultivated species, A. cruentus, A. hypochondriacus,and A. caudatus stand out and are consideredas pseudocereals, with a high seed proteincontent, a balanced amino acid composition, and ahigh lysine content (Bressani, 1989; Bressani &García-Vela, 1990; Barba de la Rosa et al., 1992;Stallknecht & Schulz-Schaeffer, 1993; Lehman, 1996;*Corresponding author. E-mail: jpastor@us.esZheleznov, Solonenko & Zheleznova, 1997; Gorinsteinet al., 2001). These Amaranthus species are cultivatedin different regions of South and Central America,India, and Nepal (Sauer, 1950; Stallknecht & Schulz-Schaeffer, 1993; Zheleznov et al., 1997; Búcaro-Segura& Bressani, 2002).Amaranthus is often difficult to characterize taxonomically,as it has few useful distinguishing featuresamongst the large number of species. Moreover,hybridization is a common phenomenon in this genus,producing many interspecific hybrids that increase thetaxonomic complexity (Greizerstein & Poggio, 1992;Lanta, Havránek & Ondreej, 2003; Wassom & Tranel,2005). It is also difficult to delimit the distributionalareas of the species, as many are cosmopolitan becauseof their capacity to adapt to the environment as well asthe large quantity of seeds produced by the plant(Costea & DeMason, 2001; Costea et al., 2004).Traditionally, Amaranthus has been divided intotwo sections: Amaranthus and Blitopsis Dumort(Aellen, 1959; Brenan, 1961; Carretero, 1979). Later,Carretero (1990) divided the genus into three sectionsand, more recently, Mosyakin & Robertson (1996),based on inflorescence and flower characters, suggesteda new classification in which the genus isdivided into three subgenera and nine sections.© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 57–63 57

SEED PROTEIN PROFILE OF AMARANTHUS 59Table 1. Localities and collection dates of the populations studiedSpeciesLocalities and voucher specimensSubgenus AmaranthusSection Amaranthus subsection AmaranthusA. retroflexus HUELVA. Lepe, 26.vii.1978, Silvestre (SEV 84403) (R-1). SEVILLA. LaLuisiana, 7.vii.2003, Juan & Pastor (215188) (R-2). Palomares delRío, 8.viii.2003, Fernández & Pastor (215189 (R-3)Section Amaranthus subsectionHibrida Mosyakin & K. R. RobertsonA. cruentus L. CÓRDOBA. Between Airport and Almodóvar del Río, 23.xi.1978,Muñoz & Ruiz de Clavijo (SEV 84640) (C-1). HUELVA. Higuera dela Sierra, 21.vii.1979, Rivera & Cabezudo (SEV 45758) (C-2).SEVILLA. Sevilla, Universidad Laboral, 25.xii.1973,Montero (SEV 20368) (C-3)A. hypochondriacus L. CÁDIZ. Algodonales, 30.ix.1978, A. Martínez (SEV 92681) (H-1).HUELVA. Between Gil Márquez and Valdelamusa, 21.vii.1979,Rivera & Cabezudo (SEV 45760) (H-2)A. powellii S. Watson ssp. bouchonii (Thell.) MADRID. Embalse de Puentes Viejas, 17.ix.1981 (SEV 113784) (P-1)Costea & CarreteroSubgenus Albersia (Kunth) Gren. & Godr.Section Blitopsis Dumort.A. blitum L. ssp. blitum SEVILLA. Sevilla, 30.vi.2003, Juan (SEV 215190) (Bl-1). La Luisiana,17.vii.2003, Juan & Pastor (SEV 215191) (Bl-2)A. deflexus L. CÓRDOBA. Los Pedroches, 6.viii.1976, Devesa (SEV 32852) (D-1).HUELVA.Galaroza, 30.viii.2003, Juan (SEV 215192) (D-2). SEVILLA. LaLuisiana, 17.vii.2003, Juan & Pastor (SEV 215193) (D-3)A. viridis L.CÓRDOBA. Córdoba, 18.viii.1978, Varela & González (SEV 83663)(V-1).HUELVA. Cartaya, viii.1979, Silvestre (SEV 83668) (V-2). SEVILLA.Sevilla, 30.vi.2003, Juan (SEV 215194) (V-3)Section Pentamorion (G. Beck) Mosyakin& K. R. RobertsonA. muricatus (Moq.) Hieron SEVILLA. Camas, 8.vii.2003, Juan & Pastor (SEV 215195) (M-1). LaLuisiana, 17.vii.2003, Juan & Pastor (SEV 215196) (M-2). San Juande Aznalfarache, 26.viii.2003, Juan (SEV 215197) (M-3)Section Pyxidium MoquinA. albus L. HUELVA. El Repilado, 17.viii.2003, Juan (SEV 215198) (A-1).SEVILLA. Camas, 8.vii.2003, Juan & Pastor (SEV 215199) (A-2). LaLuisiana, 17.vii. 2003, Juan & Pastor (SEV 215200) (A-3)A. blitoides S. Watson SEVILLA. Sevilla, 30.vi.2003, Juan (SEV 215201) (B-1). Camas,8.vii.2003, Juan & Pastor (SEV 215202) (B-2). La Luisiana,17.vii.2003, Juan & Pastor (SEV 215203) (B-3)A. graecizans L. ssp. sylvestris (Vill.) Brenan CÁDIZ. Grazalema, 28.ix.1984, Aparicio & Rowe (SEV 114345) (G-1)employing the Bray–Curtis index of dissimilarity(Bray & Curtis, 1957). The dissimilarity index wastransformed to the index of similarity (1 - dissimilarityindex ¥ 100). A dendrogram was produced from thedistance matrix using the unweighted pair groupmethod with arithmetic average (UPGMA).RESULTS AND DISCUSSIONAccording to the Osborne classification, Amaranthusseed proteins are composed of albumins, globulins,and glutelins in similar proportions and prolamins inminor amounts (Abugoch, Martínez & Añón, 2003).© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 57–63

60 R. JUAN ET AL.67674330433020.120.114.414.41 2 3 4 5 6 7 8 9 10 11Figure 1. Tricine-sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of Amaranthus seed proteins.1, A. viridis (V-3, V-2, V-1); 2, A. powellii ssp. bouchonii (P-1); 3, A. muricatus (M-2, M-1, M-3); 4, A. deflexus (D-3, D-2,D-1); 5, A. graecizans ssp. sylvestris (G-1); 6, A. blitoides (B-3, B-2, B-1); 7, A. retroflexus (R-2, R-3, R-1); 8, A. blitum (Bl-2,Bl-1); 9, A. albus (A-2, A-3, A-1); 10, A. cruentus (C-3, C-2, C-1); 11, A. hypochondriacus (H-1, H-2).The SDS-PAGE profile of the Amaranthus seed proteinsstudied showed a range of peptides varying from64 to 12 kDa (Fig. 1). The most abundant peptideswere in the ranges 64–49.2 kDa and 36.8–32.8 kDa,although the largest number of protein bands wereobserved between 25.1 and 12 kDa. Fourteen bandswere considered for the taxonomic study, althoughsome were subdivided into several isoforms based onthe differences observed in Rf.A similarity analysis based on the SDS-PAGEprofile of seed proteins was carried out. The softwareused displayed a single tree from all those possible(Fig. 2). Two major clusters (A and B) with about 45%similarity were obtained. The first cluster (group A)includes A. powellii ssp. bouchonii, A. graecizans ssp.sylvestris, and A. retroflexus, and the remaining taxastudied form group B. Within group B, two subgroups(C and D) were distinguished with 58% similarity.Group C includes five species, with A. deflexus as themost dissimilar taxon (63%). The other taxa of thisgroup form two well-defined clusters: A. muricatusand A. viridis with 79% similarity, and A. blitoidesand A. blitum with 72% similarity. With respect to thelast group (group D), A. albus clearly differs fromA. cruentus and A. hypochondriacus (72%), whosepopulations appear to be partly mixed.By contrast with the complexity of the identificationof Amaranthus species using morphological characters,our results showed that the Amaranthus taxastudied are well defined based on the seed proteinprofile; in particular, species such as A. blitoidesshowed a similarity higher than 95% in the populationsstudied. Thus, except for A. hypochondriacusand A. cruentus, the UPGMA dendrogram arrangesthe studied species in single clusters, indicating thatthe data provided by the electrophoresis profile ofseed proteins are useful in the discrimination of Amaranthustaxa at the specific level. The fact that thepopulations of A. cruentus and A. hypochondriacusare mixed could be the result of two different mechanisms.Firstly, a hybridization phenomenon, which isvery frequent in these species (Costea, Sanders &Waines, 2001a). In this case, population C3 ofA. cruentus could be a hybrid population betweenA. cruentus and A. hypochondriacus. This is possibleas this population shares the same peptide band kDawith A. hypochondriacus populations, which was notobserved in the other A. cruentus populations.Sammour (1991) also observed an intermediateprotein profile between A. viridis and A. hybridus(subgenus Albersia) in a population of A. viridis, indicatinga hybridization process between the two taxa.The second explanation for the protein profile of thispopulation could be the hybrid origin of A. hypochondriacusfrom A. cruentus and A. powellii, as proposedby Sauer (1993) and supported by some molecularstudies (Transue et al., 1994; Chan & Sun, 1997).Although the dendrogram obtained from theseed protein profile (Fig. 2) discriminates betweenspecies, it does not group these species according tothe infrageneric classification shown in Table 1.Thus, relationships established by the electrophoreticprofile of seed proteins do not match theestablished relationships based on morphological ortraditional characters. For example, A. blitum andA. blitoides, morphologically different and assigned© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 57–63

SEED PROTEIN PROFILE OF AMARANTHUS 61Figure 2. Clustering based on the seed protein profiles of 11 taxa of Amaranthus according to the Bray–Curtis similarityindex (1 - dissimilarity index ¥ 100). V-1, V-2, V-3, A. viridis; P-1, A. powellii ssp. bouchonii; M-2, M-1, M-3, A. muricatus;D-3, D-2, D-1, A. deflexus; G-1, A. graecizans ssp. sylvestris; B-3, B-2, B-1, A. blitoides; R-2, R-3, R-1, A. retroflexus; Bl-2,Bl-1, A. blitum; A-2, A-3, A-1, A. albus; C-3, C-2, C-1, A. cruentus; H-1, H-2, A. hypochondriacus.to different sections (Mosyakin & Robertson, 1996),show a similar protein profile, indicating a closerrelationship. In addition, A. albus, A. cruentus, andA. hypochondriacus are in the same group (D),although they are assigned to different sections andeven different subgenera: A. albus belongs to subgenusAlbersia section Pyxidium, whereas A. cruentusand A. hypochondriacus are included in subgenusAmaranthus section Amaranthus. Although, from amorphological point of view, A. albus is very differentfrom A. cruentus and A. hypochondriacus,recently, Costea & DeMason (2001) found similaritybetween them using leaf anatomical features, asthey observed intermediate characters between bothsubgenera in A. albus. The fact that species belongingto subgenus Albersia are distributed betweenthe three main groups (A, C, D) is congruent withtheir heterogeneous taxa composition, and supportsthe opinion of Mosyakin & Robertson (1996) thatthis subgenus needs a taxonomic revision in order todelimit new sections.In agreement with Sammour (1991) and Zheleznovet al. (1997), a correlation between the electrophoresisprofile of seed proteins and the karyological data isobserved in Amaranthus. Thus, included in group Aare taxa (A. powellii ssp. bouchonii, A. graecizans ssp.sylvestris, and A. retroflexus) with basic numbersx = 16 and 17 (Pastor, 1992). In group D, all taxa showx = 16, whereas, in group C, all species show x = 17,except for A. blitoides, which has x = 16 (Pastor,1992). This could mean that the seed protein profile isone of the phenotypical differences determined by thebasic number.In conclusion, seed proteins in Amaranthus areuseful characters to discriminate between species. Inaddition, these characters show low environmentaland evolutionary variability. The profile obtained bySDS-PAGE of seed proteins provides interestinginformation that will doubtless help in the clarificationof this complex genus. Our results show theclose relationships between species belonging todifferent taxonomic groups, such as sections orsubgenera, and allow a hybrid population to be distinguished.A more detailed study is necessary inorder to clarify the infrageneric classification of thisgenus.© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 57–63

62 R. JUAN ET AL.ACKNOWLEDGEMENTSWe thank M. Dolores Garcia for technical assistance.This work was supported by grant AGL 2004-03930.REFERENCESAbugoch LE, Martinez NE, Añón MC. 2003. Influence ofthe extracting solvent upon the structural properties ofamaranth (Amaranthus hypochondriacus) glutelin. Journalof Agriculture and Food Chemistry 51: 4060–4065.Aellen P. 1959. Amaranthus L. In: Hegi G, ed. Illustrierteflora von Mitteleuropa, Vol. 2. München: Carl HanserVerlag, 465–516.Aiassa JP, Bonamico NC, Ibañez MC, Díaz DG,Gesumaría JJ, Di Renzo MA. 2003. Caracterizaciónmolecular de híbridos simples de maíz (Zea mays L.) medianteSSR. In: XXXII Congreso Argentino de Genética,Huerta Grande, Septiembre, 2003. Córdoba: Sociedad Argentinade Genética, 21–24.Altube H, Cabello F, Ortiz JM. 1991. Characterization ofgrape varieties and rootstocks by isoenzymes from woodyparts. Vitis 30: 203–212.Barba de la Rosa AP, Gueguen J, Paredes-López O,Viroben G. 1992. Fractionation procedures, electrophoreticcharacterization, and amino acid composition of amaranthseed proteins. Journal of Agricultural and Food Chemistry40: 931–936.Bradford MM. 1976. A rapid and sensitive method for thequantitation of microgram quantities of protein utilizing theprinciple of protein–dye binding. Analytical Biochemistry72: 248–254.Bravi R, Sommovigo A, Delogu C, Merisio G. 1994. Investigationon seed species identity of Lolium rigidum tradingin Italy. Sementi Elette 40: 11–17.Bray RJ, Curtis JI. 1957. An ordination of the upland forestcommunities of southern Wisconsin. Ecological Monographs27: 325–349.Brenan JPM. 1961. Amaranthus in Britain. Watsonia 4:261–280.Bressani R. 1989. The proteins of grain amaranth. FoodResearch International 5: 13–38.Bressani R, García-Vela LA. 1990. Protein fractions inamaranth grain and their chemical characterization.Journal of Agricultural and Food Chemistry 38: 1205–1209.Búcaro-Segura ME, Bressani R. 2002. Distribución de laproteína en fracciones físicas de la molienda y tamizado delgrano del amaranto. Archivos Latinoamericanos de Nutrición52: 167–171.Carretero JL. 1979. El género Amaranthus en España. CollectaneaBotanica 11: 105–145.Carretero JL. 1990. Amaranthus. In: Castroviejo S, LainzM, López González G, Montserrat P, Muñoz Garmendia F,Paiva J, Villar L, eds. Flora Iberica plantas vasculares de laPenínsula Ibérica e Islas Baleares, Vol. 2. Madrid: RealJardín Botánico, C.S.I.C., 554–569.Chan KF, Sun M. 1997. Genetic diversity and relationshipsdetected by isozyme and RAPD analysis of crop and wildspecies of Amaranthus. Theoretical and Applied Genetics 95:865–873.Costea M, DeMason DA. 2001. Stem morphology andanatomy in Amaranthus L. (Amaranthaceae) – taxonomicsignificance. Journal of the Torrey Botanical Society 128:254–281.Costea M, Sanders A, Waines G. 2001a. Preliminary resultstoward a revision of the Amaranthus hybridus speciescomplex (Amaranthacaea). Sida 19: 931–974.Costea M, Waines G, Sanders A. 2001b. Structure of thepericarp in some Amaranthus L. (Amaranthaceae) speciesand its taxonomic significance. Aliso 20: 51–60.Costea M, Weaver SE, Tardif FJ. 2004. The biology ofCanadian weeds. 130. Amaranthus retroflexus L., A. powelliiS. Watson and A. hybridus L. Canadian Journal of PlantScience 84: 631–668.Dehmer KJ. 2003. Molecular diversity in the genus Amaranthus.In: Knüpffer H, Ochsmann J, eds. Schriften zuGenetischen Ressourcen, Band 22. Bonn: Rudolf Mansfeldand Plant Genetic Resources, 208–215.Drzewiecki J. 2001. Similarities and differences betweenAmaranthus species and cultivars and estimationof outcrossing rate on the basis of electrophoretic separationsof urea-soluble seed proteins. Euphytica 119: 279–287.Duvall MR, Biesboer DD. 1989. Comparisons of electrophoreticseed protein profiles among North American populationsof Zizania. Biochemical Systematics and Ecology 17:39–43.El Aydam M, Bürki HM. 1997. Biological control of noxiouspigweeds in Europe: a literature review of the insect speciesassociated with Amaranthus spp. worldwide. BiocontrolNews and Information 18: 11–20.Esparza-Sandoval S, Alejandre-Iturbide G, Herrera-Arrieta Y. 1996. Foliar anatomy and morphology of seedsin some Mexican species of Amaranthus. Phytologia 81:273–281.Gardiner SE, Forde MB. 1987. Sds polyacrylamide gelelectrophoresis of grass seed proteins: a method for cultivaridentification of pasture grasses. Seed Science and Technology15: 663–674.Gardiner SE, Forde MB. 1988. Identification of cultivarsand species of pasture legumes by sodium dodecyl sulphatepolyacrylamide gel electrophoresis of seed proteins. PlantVarieties Seeds 1: 13–26.Gardiner SE, Forde MB, Slack CR. 1986. Grass cultivaridentification by sodium dodecylsulphate polyacrylamide gelelectrophoresis. New Zealand Journal of AgriculturalResearch 29: 193–206.Gorinstein S, Delgado-Licon E, Pawelzik E, HeriyatiPermandy H, Weisz M, Trakhtenberg S. 2001. Characterizationof soluble amaranth and soybean protein basedon fluorescence, hydrophobicity, electrophoresis, amino acidanalysis, circular dichroism, and differential scanning calorimetrymeasurements. Journal of Agricultural and FoodChemistry 49: 5595–5601.Gorinstein S, Moshe R. 1991. Evaluation of four Amaranthusspecies through protein electrophoretic patterns and© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 57–63

SEED PROTEIN PROFILE OF AMARANTHUS 63their amino acid composition. Journal of Agricultural andFood Chemistry 39: 851–854.Greizerstein JE, Poggio L. 1992. Estudios citogenéticos deseis híbridos interespecíficos de Amaranthus (Amaranthaceae).Darwiniana 31: 159–165.Gudu S, Gupta VK. 1988. Electrophoresis as an aid foridentification of various species and cultivars of grain amaranths.Acta Horticulturae 218: 230–238.Johnson BL, Barnhart D, Hall O. 1967. Analysis of genomeand species relationships in the polyploid wheats by proteinelectrophoresis. American Journal of Botany 54: 1089–1098.Lanta V, Havránek P, Ondreej V. 2003. Morphometryanalysis and seed germination of Amaranthus cruenthus,A. retroflexus and their hybrid (A. ¥ turicensis). Plant SoilEnvironment 49: 364–369.Leconte A, Lebrun P, Nicolas D, Seguin M. 1994.Electrophoresis: application to Hevea clone identification.Plantations, Recherche, Développement 1: 28–36.Lehmann JW. 1996. Case history of grain amaranth as analternative crop. Cereal Foods World 41: 399–411.Misset MT, Fontenelle C. 1992. Protein relationshipsbetween natural populations of Ulex europaeus and U. galli(Faboideae, Genisteae) and their hybrids. Plant Systematicsand Evolution 179: 19–25.Mosyakin SL, Robertson KR. 1996. New infrageneric taxaand combinations in Amaranthus (Amaranthaceae).Annales Botanici Fennici 33: 275–281.Mujica A, Jacobsen SE. 2003. The genetic resources ofAndean grain amaranths (Amaranthus caudatus L.,A. cruentus L. and A. hypochondriacus L.) in America. PlantGenetic Resources Newsletter 133: 41–44.Pasha MK, Sen SP. 1991. Seed protein patterns of Cucurbitaceaeand their taxonomic implications. BiochemicalSystematics and Ecology 19: 569–576.Pastor J, ed. 1992. Atlas cromosómico de la flora vascular deAndalucía occidental. Sevilla: Universidad de Sevilla.Sammour RH. 1991. Using electrophoretic techniques invarietal identification, biosystematic analysis, phylogeneticrelations and genetic resources management. Journal ofIslamic Academy of Sciences 4: 221–226.Sauer JD. 1950. The grain amaranths. A survey of theirhistory and classification. Annals of the Missouri BotanicalGarden 37: 561–632.Sauer JD. 1993. Historical geography of crop plants. A selecroster. Boca Raton, FL: CRC Press, 9–14.Schägger H, von Jagow G. 1987. Tricine-sodium dodecylsulfate-polyacrylamide gel electrophoresis for the separationof proteins in the range from 1 to 100 kDa. AnalyticalBiochemistry 166: 368–379.Stallknecht GF, Schulz-Schaeffer JR. 1993. Amaranthrediscovered. In: Janick J, Simon JE, eds. New crops. NewYork: Wiley, 211–218.Sun M, Chen H, Leung FC. 1999. Low-Cot DNA sequencesfor fingerprinting analysis of germplasm diversity and relationshipsin Amaranthus. Theoretical and Applied Genetics99: 464–472.Transue DK, Fairbanks DJ, Robinson LR, AndersenWR. 1994. Species identification by RAPD analysis of grainamaranth genetic resources. Crop Science 24: 1385–1389.Wassom JJ, Tranel PJ. 2005. Amplified fragment lengthpolymorphism-based genetic relationships among weedyAmaranthus species. Journal of Heredity 96: 410–416.Xu F, Sun M. 2001. Comparative analysis of phylogeneticrelationships of grain amaranths and their wild relatives(Amaranthus; Amaranthaceae) using internal transcribedspacer, amplified fragment length polymorphism, anddouble-primer fluorescent intersimple sequence repeatmarkers. Molecular Phylogenetics and Evolution 21: 372–387.Zheleznov AV, Solonenko LP, Zheleznova NB. 1997. Seedproteins of the wild and the cultivated Amaranthus species.Euphytica 97: 177–182.© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 57–63