Currently, more than 70 % of maize is used for food and fodder; therefore, grain quality improvement can increase its nutritive and energy value. Deficiency of two essential amino acids (lysine and tryptophan) significantly reduces the nutritional quality of maize proteins. However, in comparison to conventional maize varieties, opaque2 (o2) mutants have greater contents of lysine and tryptophan in their endosperm proteins and their bioavailability is better. The aim of the study was identification of maize accessions with high-quality protein. A collection of maize accessions of various ecogeographical origins was studied by molecular methods. This approach was expected to improve maize breeding efficiency. We collected 54 maize genotypes differing in grain quality performance. Amplification with three specific markers to the opaque-2 gene (phi057, phi112 and umc1066) revealed homozygous recessive o2 genotypes, associated with improved nutritional quality of the protein. UREA-PAG electrophoresis of zein proteins was used for Quality Protein Maize (QPM) identification. In addition to the mutant o2 allele, QPM contains genetic modifiers that convert starchy endosperm of o2 mutant to the hard vitreous phenotype. The selected QPM accessions are of interest for maize breeding programs aimed at grain quality improvement. The use of the markers to o2 and modifier genes accelerates the development of QPM varieties and significantly reduces the labor and financial costs of their production.
About The Authors:
O. A. Orlovskaya. Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk, Republic of Belarus, Russian Federation
S. I. Vakula. Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk, Republic of Belarus, Russian Federation
A. V. Kilchevsky. Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk, Republic of Belarus, Russian Federation
1. Babu R., Prasanna B.M. Molecular breeding for Quality Protein Maize (QPM). Genom Plant Genetic Res. 2014489-505. DOI: 10.1007/978-94-007-7575-6_21
2. Danson J.W., Mbogori M., Kimani M., Lagat M., Kuria A., Diallo A. Marker assisted introgression of opaque2 gene into herbicide resistant elite maize inbred lines. African J. Biotechnol. 2006;5(24):2417-2422. DOI:10.5897/AJB06.499
3. Esen A. A proposed nomenclature for the alcohol-soluble proteins(zeins) of maize (Zea mays L.). J. Cereal Sci. 1987;5(2):117-128. DOI: 10.1016/S0733-5210(87)80015-2
4. Geetha K.B., Lending G.R., Lopes M.A., Wallace J.C., Larkinset B.A. opaque-2 modifiers increase γ-zein synthesis and alter its spatial distribution in maize endosperm. Plant Cell. 1991;3(11):1207-1219. DOI:http:/dx.doi.org/10.1105/tpc.3.11.1207
5. Gibbon B.C., Larkins B.A. Molecular genetic approaches to developing quality protein maize. Trends Genet. 2005;21(4):227-233. DOI: 10.1016/j.tig.2005.02.009
6. Habben J.E., Kirleis A.W., Larkins B.A. The origin of lysine-containing proteins in opaque-2 maize endosperm. Plant Mol. Biol. 1993;23(4):825-838. DOI: 10.1007/BF00021537
7. Holding D.R. Recent advances in the study of prolamin storage protein organization and function. Front Plant Sci. 2014;5:276. DOI: 10.3389/fpls.2014.00276
8. Holding D.R., Otegui M.S., Li B.L., Meeley R.B., Dam T., Hunter B.G., Jung R., Larkins B.A. The maize floury1 gene encodes a novel endoplasmic reticulum protein involved in zein protein body formation. Plant Cell. 2007;19(8):2569-2582. DOI: 10.1105/tpc.107/053538
9. Motto M., Balconi C., Hartings H., Rossi V. Gene discovery for improvement of kernel quality-related traits in maize. Genetika. 2010;42(1):23-56. DOI: 10.2298/GENSR1001023M
10. Schmidt R.J., Burr F.A., Aukerman M.J., Burr B. Maize regulatory gene opaque2 encodes protein with a «leucine zipper» motif that binds to zein DNA. Proc. Natl. Acad. Sci. USA. 1990;87(1):46-50.
11. STB 1710-2006. utv. i vved. v dejstvie Postanovleniem Gosstandarta Respubliki Belarus’ ot 30 dekabrja 2006 g. № 66. Semena kukuruzy. Metod opredelenija urovnja gibridnosti semjan pervogo pokolenija, ocenka tipichnosti i markirovanie inbrednyh linij [STB 1710-2006.
12. approved. and enter. by a Resolution of the State Standard of the Republic of Belarus on December 30, 2006 № 66. Seeds of maize. Hybridization level detection method for seeds of first generation, typicality evaluation and inbred lines labeling]. Minsk, 2006.
13. Vasal S.K. The quality protein maize story. Food Nutr. Bull. 2000;21:445-450.
14. Wu Y., Holding D.R., Messing J. Gamma-zein is essential for endosperm modiﬁcation in quality protein maize. Proc. Natl Acad. Sci.USA. 2010;10729):12810-12815. DOI: 10.1104/pp.113.230961
15. Yang W., Zheng Y., Ni S., Wu J. Recessive allelic variations of three microsatellite sites within the O2 gene in maize. Plant Mol. Biol. Rep. 200422(4):361374. DOI: 10.1007/BF02772679