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

COMPONENTS OF FRIABILINS AND VARIABILITY IN BREAD WHEAT AND EINKORN

CORONA V.

Borsisti@iscsal.it

As new data about plant genomes and proteins become available, correspondences between genes and codified proteins are found. Both molecular (RNA and DNA) and biochemical points of view furnish us a powerful means for studying new alleles, as well as protein regulation and function.

Cereal seeds are definitely a suitable subject for application of genomics and proteomics; their protein are abundant, in some cases accurately characterized (HMW glutenins, zeins) and primarily important for the quality of the end products.

Friabilins, the wheat proteins determining hardness constituted by two main components named puroindolines ( pins) have been fractionated by A-PAGE in their isoforms and alleles. In wheat and most Triticae the two main isoforms of puroindolines, pina and pinb, interact with starch granule and polar lipids, raising grain softness.

Even if they are highly conserved among various species (but absent in tetraploid wheat), specific amino acid substitutions in puroindolines were found to result in bands with different mobility in A-PAGE. Furthermore the number of isoforms and/or their amount were higher in diploid wheat, rye and oat, than in bread wheat, this affecting grain hardness. Intraspecific variability was found to be low in diploids (Triticum monococcum) and exaploid wheat (Triticum aestivum), the latter species showing three alleles for pinb and one for pina.

Pedigrees of Italian bread wheat lines confirm that pins affect directly grain texture. In facts mutated pins, introgressed in Italian germplasm from foreign wheat lines (from Mexico, Russia, etc.), proved to be always inherited together with the “grain hardness” trait.

The biological function of pins and their mode of action in affecting hardness are still unclear and perhaps not related; however, considering their ubiquity among Triticae they should have important function in seed physiology of wheat.