~ 350 ~ Journal of Pharmacognosy and Phytochemistry 2019; SP1: 350-354 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2019; SP1: 350-354 Mehak Sethi Department of Biochemistry, College of Basic Science and Humanities, Punjab Agricultural University, Ludhiana, Punjab, India Dharam Paul Chaudhary Indian Institute of Maize Research, Ludhiana, Punjab, India Correspondence Mehak Sethi Department of Biochemistry, College of Basic Science and Humanities, Punjab Agricultural University, Ludhiana, Punjab, India (Special Issue- 1) 2 nd International Conference “Food Security, Nutrition and Sustainable Agriculture - Emerging Technologies” (February 14-16, 2019) Prolamins and Glutelins as protein markers to distinguish normal lines from QPM germplasm Mehak Sethi and Dharam Paul Chaudhary Abstract Maize protein quality is poor due to high content of zein protein lacking essential amino acids: lysine and tryptophan. Opaque2 mutants were discovered having high lysine, tryptophan due to reduction zeins with pleotropic effects such as soft and chalky kernel. Quality protein maize (QPM) were developed with high protein quality and vitreous kernel texture. Present study was planned to establish protein markers to distinguish normal maize from QPM. Kernels were harvested from normal and QPM lines for estimation of protein fractions from extracted endosperm. Results revealed that prolamin and glutelin are the two major fractions affected by opaque-2 mutation. Prolamin is highest in normal (44.9%) and least in QPM (8.94%) whereas, glutelin is more in QPM (32.9%) than normal lines (17.6%). Hence out of all protein fractions, prolamin and glutelin show maximum variation, so can be used as precise and cost effective protein markers to differentiate normal lines from QPM. Keywords: Normal, QPM, protein, prolamin, glutelin 1. Introduction Maize (Zea mays) is the world’s third leading cereal crop, after wheat and rice and is a staple food for a large segment of population [1] . A mature maize kernel constitutes 80-85% of endosperm, followed by germ (9-10%) and pericarp (5-6%). Endosperm the major edible part of maize kernel is composed of 70% starch and 8-10% protein and relatively low fat content [2] . Maize endosperm consists of two types of protein i.e., zein and non-zein protein. Zein, the alcohol soluble protein (prolamin, prolamin-like protein), is the major seed storage protein of maize kernel and constitutes approximately 50-70% of maize endosperm [3] . The non-zein protein consists of globulins (3%), glutelins (34%) and albumins (3%). Protein quality of maize endosperm is poor because it is devoid of essential amino acids, particularly lysine and tryptophan due to higher proportion of nutritionally poor zein protein, whereas non-zein fraction has balanced proportion of essential amino acid but there content in normal maize is comparatively low which decreases the overall nutritional quality of maize protein [4] . Discovery of opaque-2 mutant led to, the development of nutritionally improved maize [5] . Opaque-2 gene codes for a transcriptional factors that belongs to basic region-leucine zipper family [6] and controls the expression of other genes. The nutritional quality of opaque-2 mutants was increased due to overall reduction of (50-70%) zein protein, specifically the 22- kDa alpha zeins and subsequently the increase in non-zein fractions including globulin, albumin and glutelins [7] . However, the pleotropic effects such as kernel opaqueness, yield loss and disease susceptibility halted the success of opaque-2 mutant varieties [8] . Later, combination of opaque-2 mutants with endosperm modifiers led to the development of quality protein maize (QPM) which has similar kernel texture as that of normal maize but possess higher protein quality as that of opaque-2 mutants. Breeding programs have led to development of high quality maize varieties and there screening for protein quality is necessary, traditional screening method involve lysine and tryptophan estimation by papain hydrolysis method which is costly so there is demand to develop substitutes to the available method. Present study is targeted to investigate the protein fractions which are majorly effected by opaque-2 mutation and to develop cost effective method of QPM screening.