OCCURRENCE OF FRIABILIN, A LOW-MOLECULAR-WEIGHT PROTEIN ASSOCIATED WITH GRAIN SOFTNESS, ON STARCH GRANULES ISOLATED FROM SOME WHEATS AND RELATED SPECIES

Proteins of apparent Mr, 14–15k by SDS—PAGE were identified on starches washed by aqueous procedures from soft endosperms of diploid Triticum and Aegilops spp. (AA, BB, DD and SS genomes). These proteins were analogous to the previously reported friabilins of hexaploid wheats (AABBDD genomes) and diploid rye (Secale cereale, RR genome) and gave clear positive reactions in an ELISA test based on an antibody to soft wheat (T. aestivun) friabilin. Little or no friabilin-like protein was found on starches from hard endosperms of tetraploid wheats (AABB and AAGG genomes), diploid barley (HH genome) or Aegilops umbellulata (UU genome). It is proposed that these proteins should be designated friabilins-A, -B, -D, -S and -R, respectively, to identify the genome carrying the controlling genes. © 1992, Academic Press Limited. All rights reserved.