Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

THE GLUTENIN POLYMER STRUCTURE IN RELATION TO WHEAT QUALITY PROPERTIES: CHARACTERIZATION OF LMW-GS GENES, ANALYSIS OF TRANSGENIC PLANTS, AND IN VITRO RE-OXIDATION OF GLUTENIN SUBUNITS

MASCI S., D’OVIDIO R., PATACCHINI C., SCOSSA F., SIMEONE M., MONARI A.M., SELLA L., LAFIANDRA D.

Dipartimento di Agrobiologia e Agrochimica, Università della Tuscia, Via San Camillo de Lellis, 01100 Viterbo, Italy

masci@unitus.it

glutenin, glutenin polymer, glutenin subunits, glutenin subunits genes, wheat quality

Wheat technological quality is strictly dependant on endosperm proteins. Among these, glutenin subunits, both high (HMW-GS) and low (LMW-GS) molecular weight, are the most important. They are linked together by covalent bonding in forming the so-called “glutenin polymers”, whose size and composition are directly correlated to visco-elastic properties. Because of the huge size of the glutenin polymers (up to millions) their structure is poorly understood.

In order to know better how glutenin subunits are organized in polymers and draw conclusion about their influence on wheat quality, we have characterized several LMW-GS genes, with particular attention to those present at Glu-B3 locus, since their products are the most directly correlated to gluten quality. We have used such genes to manipulate gluten composition in bread wheat. Homozygous T₃ and T₄ seeds of one line overexpressing the LMW-GS transgene have been characterized at biochemical level in order to determine its influence on the polymer structure. Analysis of endosperm proteins of transgenic seeds show that the transgene product increases the size of the glutenin polymer, thus positively affecting gluten quality. Moreover, since transgenic wheat lines were prepared by co-transformation of the LMW-GS gene and the bar gene, we show that the marker gene has been easily removed through segregation.

We are pursuing the definition of the glutenin polymer structure and its correlation with quality properties also through in vitro re-oxidation of native or heterologously expressed in Escherichia coli HMW-GS and LMW-GS, differing in cysteine number and length of the repetitive domain. The re-oxidation patterns obtained are being related to structural characteristics.