The Effects of He-Ne laser and Enhanced Ultraviolet-B radiation on ASF1 in Wheat Seedlings

Abstract

ASF1 (Anti-silencing function 1) is an evolutionarily conserved H3/H4 histone chaperone and it contains two genes in higher plants, including ASF1A and ASF1B. Information concerning ASF1 in response to He-Ne laser and UV -B radiation in wheat is currently limited. In this study, the seedlings of wheat (‘ML7113’) were subjected to enhanced UV-B radiation (10.08KJ·m−2·d−1) for 7 days and then were exposed to He-Ne laser irradiation with 5mW·mm−2 for 2 min each day without ambient light. We explored the transcripts of ASF1A and ASF1B in each treatment group using RT-PCR. In addition, total proteins were extracted from the 7-day-old wheat leaves, assayed by SDS-PAGE and then identified by western blot. The results showed that the transcripts of ASF1A and ASF1B were increased following UV-B radiation compared with the control. However, when seedlings were subjected to elevated UV-B-damaging radiation followed by He-Ne laser irradiation, the expression of ASF1A and ASF1B were significantly lower than UV-B radiation alone. So was the content of ASF1 proteins. These results suggest that He-Ne laser has an active role in repairing the UV-Bdamaging effects. In order to further investigate the function of ASF1, dynamic arrangements of ASF1 in wheat root-tip cells were observed with confocal laser scanning microscopy (CLSM). It was found that the subcellular localization of ASF1 proteins was mainly in the two poles of cell in mitosis, suggesting that ASF1 may be involved in the separation of chromosomes.