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Wheat Information Service
Number 76: 77-79 (1993)


Detection of HMW glutenin genes by DNA hybridization and breadbaking quality of amphidiploid synthesized between Aegilops squarrosa and Secale cereale.

S. Sekiguchi1, J. Ono1, and T. Taira2

1 Central Laboratory, Nippon Flour Mills Co. Ltd., Atsugi, Kanagawa
2 Lab. of Genetics and Plant Breeding, College of Agriculture, Univ. of Osaka Prefecture, Sakai, Osaka 593, Japan


We have synthesized a new amphidiploid having genomes DDRR between Aegilops squarrosa var. typica and Secale cereale cv. Prolific (Kawakubo and Taira 1992). High molecular weight (HMW) glutenin subunits are governed by genes located on long arms of homoeologous group 1 chromosomes in hexaploid wheat (Boyd et al 1967, Payne et al 1979) and all three HMW glutenin loci are Glu-A1, Glu-B1, and Glu-D1 (Payne and Lawrence 1983). Since alleles at these three loci have shown differential effects on bread-baking quality in hexaploid wheat, the structure of HMW glutenin genes of genomes D and R, and the flour quality of amphidiploid were investigated in this study.


Identification and comparison of genomic DNA restriction-fragment of HMW glutenin genes between amphidiploid and its direct parents

Amino acid sequence of protein encoded by a HMW glutenin cDNA fragment (777bps) isolated from hexaploid wheat cv. Park consisted of repetitive units of two motif, PGQGQQ and GYYPTSLQQ, which were typical to the amino acid sequence of common region in HMW glutenin proteins. Enzyme-digested genomic DNA fragments from F3 progeny of amphidiploid and its direct parents, tetraploid Ae. squarrosa (genomes DDDD) and S. cereale (RRRR), were probed with the cDNA fragment. The hybridization patterns of DNA restriction fragments were as follows
(Fig. 1): in EcoRI digestion, five bands were found in amphidiploid, two bands in Ae. squarrosa and three bands in S. cereale; in BamHI digestion, five bands were found in amphidiploid, two bands in Ae. squarrosa and three bands in S. cereale; in HindIII digestion, five bands were found in amphidiploid, two bands in Ae. squarrosa and four bands in S. cereale. In particular, the band c in EcoRI digestion of S. cereale (Fig. 1B, lane 8) had slightly large molecular weight than the band a of amphidiploid (lane 7), and the band d (lane 8) was the same as the band a. It seems that the band c in S. cereale splits into two fragments such as bands a and b in amphidiploid.


Comparison of HMW glutenin proteins of amphidiploid and its parents

Glutenin proteins deposited in endosperm were extracted and separated by SDS PAGE
(Fig. 2). The distribution of HMW glutenin proteins in diploid seeds was different from that in tetraploid seeds in both parental lines. Origin of protein bands of amphidiploid was considered as follows: band a was derived from either S. cereale or Ae. squarrosa; bands b, c, e and f from S. cereale; band d from Ae. squarrosa.


Baking tests

Bread was baked with 30 g of flour by straight dough procedure. Because of bad weather condition at harvesting time, amphidiploid flour was low quality, and thus the dough was sticky and runny. Nevertheless, a loaf of amphidiploid was increased by 29% in volume compared with that of rye, although amphidiploid showed 49% in volume of bread wheat (
Fig. 3). Wet gluten (3%) was obtained from amphidiploid flour, but no gluten was detected in rye flour.

These results showed that the amphidiploid in which Glu-1D gene of glutenin subunits was introduced from Ae. squarrosa had improved bread-baking quality in comparison with rye.


References

Boyd WJR, Lee JW, and Wrigley CW (1967), The control of wheat gluten synthesis at the genome and chromosome level. Experientia 23: 332-333.

Kawakubo J and Taira T (1992) Intergeneric hybrids between Aegilops squarrosa and Secale cereale and their meiotic chromosome behavior. Plant Breeding 109: 108-115.

Payne Pl, Law CN, and Mudd EE (1979) Control by homoeologous group 1 chromosome of the high molecular weight subunits of glutenin: A major protein of wheat endosperm. Theor. Appl. Genet. 58: 113-120.

Payne PI, and Lawrence GJ (1983) Catalogue of alleles for the complex gene loci, Glu-A1, Glu-B1 and Glu-D1 which code for high molecular weight subunits of glutenin in hexaploid wheat. Cereal Res. Commun. 11: 29-35.

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