Heritable somaclonal variation in gliadin proteins of wheat plants derived from immature embryo callus culture

Summary

Fertile r₀ plants of the winter wheat line ND7532 (Triticum aestivum L.) were regenerated from callus tissue after 60–190 days in culture. Seeds produced from these self-pollinated plants were planted in the field. Of the 5586 R₁ plants, 32 differed for one or more agronomic traits from plants not passed through tissue culture process. Gliadin electrophoregrams were prepared from bulk samples of R₂ seed from these 32 plants. Four of the 32 produced gliadin patterns different from controls, so 12 seeds of each of these four lines were examined individually. Three of the four mutant lines were fixed for the presence of a mutant protein of 50 relative mobility units (RMU) and the corresponding loss of a parental protein of 26 RMU. The remaining line segregated for the presence/absence of band 50 and the corresponding loss/retention of band 26. The mutant protein of 50 RMU was never seen in control plants. This indicated that either band 50 was coded for by a mutant gene allelic to the gene that coded for band 26 or that bands 26 and 50 were coded for by two different structural alleles under the control of a common regulatory locus. Each of the 12 seeds from the four mutant lines contained a prominent protein band at 30 (RMU), which was only observed as a faint band in one control seed. The types of variation in gliadin patterns observed in somaclones of ND7532 were similar to those reported for the line ‘Yaqui 50E’, except that, gliadin changes occurred less frequently in ND7532.