Effect of Allelic Variation in Triticin on Bread- and Chapati-Making Qualities of Wheat (Triticum aestivum)

Sonia Goel,Pradeep K Singh,Neha Jain,Anju M Singh,Meenal Rathore,Sapna Grewal,Binay K Singh,Nagendra K Singh,Arvind K Ahlawat

doi:10.1007/s40003-015-0150-1

Abstract

Triticin, a legumin-like storage protein of wheat endosperm, was discovered nearly three decades ago but so far there is no report on its effect on the processing quality of wheat that is thought to be determined primarily by prolamins, its major seed storage proteins. To investigate the effect of different classes of seed proteins on wheat quality using a genetic reconstitution approach, we produced 31 near-isogenic lines (NILs) with different alleles of triticin, high molecular weight glutenin subunits (HMW-GS), low molecular weight glutenin subunits (LMW-GS), gliadins and albumins in a common genetic background of wheat variety HD2329 and analysed different quality parameters over a period of 4 years. The NILs did not differ in their flour protein content, but showed significant differences in SDS-sedimentation volume, Farinograph dough stability, bread loaf volume and chapati quality score. Main focus was on triticin for which two NILs with alleles Tri-A1a and Tri-D1a derived from a high-quality Indian wheat variety K68 were analysed. Positive effects of these triticin alleles on dough physical properties, bread loaf volume and chapatti quality score were quite large, comparable to the widely known effect of HMW-GS 5 + 10. Specific alleles of HMW-GS, Glu-A1a (subunit 1), Glu-B1b (subunits 7 + 8), Glu-B1i (subunits 17 + 18) and Glu-D1d (subunits 5 + 10) showed strong positive effects, whereas null allele Glu-A1c showed negative effect on the quality of recipient variety HD2329. Similarly, different alleles of LMW-GS showed varying effects with Glu-A3d, Glu-A3e and Glu-D5a showing positive effects, Glu-A3c showing negative effect and Glu-A3a showing no significant effect. Gliadin alleles generally showed negative effects, whereas albumins showed no significant effect. While results with glutenin and gliadin alleles were as expected, we show here for the first time a significant effect of triticin on the wheat flour quality, suggesting that end-use quality of wheat varieties can be improved by combining specific alleles of triticin.

Highlights

The end-use quality of wheat grain is determined by its protein, starch and lipids constituents of whom gluten proteins play a pivotal role
Total thirty-one near-isogenic lines (NILs) were developed with different seed storage protein alleles in the common genetic background of bread wheat variety HD2329
high molecular weight glutenin subunits (HMW-GS) NILs differed for the targeted high molecular weight (HMW) subunit only, and their profiles for other HMW subunits, low molecular weight (LMW) subunits, gliadin, albumin and triticin proteins were identical to the recurrent parent HD2329 (Fig. 3)

Summary

Introduction

The end-use quality of wheat grain is determined by its protein, starch and lipids constituents of whom gluten proteins play a pivotal role. Apart from the role of individual glutenin subunits, studies on native proteins without reduction of their disulphide bonds have shown that dough strength and bread-making quality are positively correlated with the proportion and molecular size distribution of polymeric proteins in the total flour protein [5, 9, 33, 34]. The LMW subunits have been quite difficult to study by electrophoresis due to their overlapping size with gliadin polypeptides but after development of a simplified SDS-PAGE procedure, it was shown that allelic differences at Glu-A3, Glu-B3 and Glu-D3 loci coding for LMW glutenin subunits are important in determining the dough properties and breadmaking quality [5, 8, 13, 35]

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