The influence of the rye genome on the accumulation of HSP18 and HSP70 transcripts in a wheat genetic background

The influence of the rye genome on the accumulation of HSP18 and HSP70 transcripts in a wheat genetic background was examined in the wheat/rye hybrid triticale (Triticum aestivum cv Chinese Spring x Secale cereale cv Imperial). To quantify the amount of transcript accumulation in wheat, rye, triticale, and in the disomic and the ditelosomic rye addition lines to wheat, we used two independant methods, namely (1) Northern dot-blot hybridizations and (2) an exami-nation of the in-vitro translation products. Both the HSP18 and HSP70 transcripts were expressed at similar levels in Chinese Spring wheat, Imperial rye, and triticale. The HSP18 and HSP70 transcript levels of the disomic and the ditelosomic addition lines to wheat were compared to the transcript levels in wheat. With the exception of 5R, increased levels of HSP18 and/or HSP70 transcripts were expressed in all six of the remaining disomic addition lines. A neutral or suppressed level of HSP18 and HSP70 transcripts accumulated in addition lines 5R, 5RL, 5RS and 6RL. Wheat/rye genomic interactions influenced the level of heat-shock gene transcript accumulation in triticale. Rye chromosome 5R, and in particular both arms of rye chromosome 5R (5RL and 5RS), had a strong suppressive influence on the accumulation of wheat HSP18 and HSP70 transcripts. The genes controlling rye HSP expression appeared to be widely distributed throughout the rye genome.