Differential effects of high-lysine mutations on the accumulation of individual members of a group of proteins encoded by a disperse multigene family in the endosperm of barley (Hordeum vulgare L.)

Abstract

The CM proteins are a group of major salt-soluble endosperm proteins encoded by a disperse multigene family. The effects of high-lysine mutations on the net accumulation in barley endosperm of three members of this group (CMa, CMb, and CMe) have been investigated. Genes CMa, CMb and CMe are located in chromosomes 1, 4, and 3 respectively. Protein CMe has been found to be identical with a previously described trypsin inhibitor. The three proteins have been quantified in the different genetic stocks by HPLC. The different high-lysine mutations have different effects on the expression patterns of the three genes: CMe is markedly decreased and CMa and CMb are increased in mutant Risø 1508, whereas all three proteins are decreased in Risø 527 and increased in Risø 7 with respect to the wild-type Bomi; CMa and CMb are increased and CMe is unaffected in mutant Risø 56 with respect to the wild-type Carlsberg II; and protein CMe is markedly decreased in Hiproly barley as compared with its sister line CI4362. The implications of these results in connection with the evolution of CM proteins and with the characterization of high-lysine mutations are discussed.