A study of genomic interaction in the wheat/rye hybrid triticale, using heat-shock protein expression

The expression of heat-shock proteins (HSPs) was used to study the interactions of the genetically different genomes in wheat and in the wheat-rye hybrid triticale.;This suppressive influence of the rye genome on wheat HSP expression was studied further using rye disomic additional lines to wheat. Results from two-dimensional protein gels showed that the addition of rye chromosomes 1R, 3R and 5R to wheat resulted in the expression of the least unique wheat HSPs. In contrast, addition line 4R had the least suppressive influence on wheat HSP expression by showing expression of the most unique wheat HSPs.;The HSP18 and HSP70 transcript levels from rye disomic and ditelosomic additions to wheat were determined using Northern analyses and in vitro translation assays. The wheat, rye and triticale HSP18 and HSP70 transcript levels were all similar. With the exception of addition line 5R, which was unchanged, expression of one or both of these transcripts was enhanced in the remaining six disomic addition lines relative to wheat. Addition lines 5RL and 5RS showed a reduced level of the HSP18 and HSP70 transcripts, relative to wheat.;Since (1) the rye genome was the dominant parent in the expression of triticale HSPs, (2) the rye genome suppressed wheat HSP expression, and (3) the group of 5R addition lines showed neutral or reduced levels of HSP transcripts, the suppressive influence of the rye genome on wheat HSP expression was assigned to 5R.;The majority of the HSPs expressed in 6X Triticum aestivum (AABBDD), were from the A and B genomes while those of the D genome were suppressed. The predominant HSPs expressed in 8X triticale (AABBDDRR) were from the rye (Secale cereale) R genome while those from the wheat genomes were suppressed.;Since six of the seven disomic addition lines showed increased levels of heat-shock transcripts relative to wheat, then the rye genes controlling HSP expression in triticale must be dispersed throughout the rye genome and interact with the wheat genomes.