Abstract
High-temperature stress (30oC /25oC) for 5 days during early development and differentiation of anther cell layers induced male sterility in barley plants. Tapetum and pollen mother cells completely failed to differentiate and "no pollen grain" phenotype was revealed at anthesis. Several transcripts including histone and glycine-rich RNA-binding protein genes drastically increased just before development and differentiation of anther cell layers. In contrast, under the high-temperature condition, the significant induction did not occur and also normally abundant mRNAs, such as 60S ribosomal protein L27a and glyoxalase I, were reduced. We found a strong correlation between the failure of transcriptional re-activation following down-shift to optimal temperature and the sterility. Hyper-phosphorylation of the CTD ser-5 of RNA polymerase II largest subunit occurred under high-temperature condition. These results suggest that the early development and differentiation of barley anthers is sensitive to high-temperature stress due to inhibition of general transcription.
