增强 UV-B 辐射对拟南芥fas1突变体的影响

Effects of Enhanced UV-B Radiation on fas1 Mutants of Arabidopsis thaliana

随着臭氧层的变薄和臭氧空洞的出现,到达地球表面的UV-B辐射明显提高,对生物的生长和发育产生了一定的影响。拟南芥中FAS1同源物的敲除也没有使其出现致死表型,植物仍然能够存活,只是在胚后器官发生时出现缺陷,如激活其顶端分生组织处的沉默基因,导致茎干宽扁,相应的叶序和花序结构紊乱。因此,FAS1能够稳定异染色质,使其中的基因保持沉默。以野生型和fas1突变体拟南芥为材料,对比了不同条件下野生型和fas1突变体拟南芥的发芽势和发芽率、根长以及根尖分生区有丝分裂细胞的末期,结果表明在正常生长条件下WT和fas1突变体的发芽势和发芽率、根长以及根尖分生区细胞在有丝分裂末期的形态都没有显著差异。而在UV-B辐射条件下,对比不同组之间的发芽势和发芽率、根长,结果表明,WT+UV-B组低于WT组,fas1+UV-B组低于fas1组,fas1+UV-B组低于WT+UV-B组,且差异均达到显著水平。此外,在UV-B辐射条件下,观察到在fas1+UV-B组中,有丝分裂也表现出一定的异常现象。这些结果表明,FAS1基因功能的缺失可能是导致fas1突变体对UV-B胁迫敏感的诱因之一。

With the thinning of the ozone layer and the emergence of ozone holes,the UV-B radiation reaching the Earth’s surface is significantly increased,which has a certain impact on the growth and development of organisms.The knockout of the FAS1 homolog in Arabidopsis thaliana did not cause a lethal phenotype,and the plant was still alive,only when the post-embryonic organ developed defects,such as activation of the silencing gene at its apical meristem,resulting in stem wide and flat,the corresponding leaf order and inflorescence structure were disordered.Therefore,FAS1 was able to stabilize heterochromatin and kept the genes in silent.In this paper,the wild-type and fas1 mutants A.thaliana were used as experimental materials to compare the germination potential and germination rate,root length and the terminal phase of mitotic cells in the wild-type and fas1 mutant A.thaliana under different conditions.The results showed that there was no significant difference in germination potential,germination rate,root length and morphology of apical meristem cells at the end of mitosis under normal growth conditions.Under UV-B radiation conditions,the germination potential,germination rate and root length between different groups were compared.The results showed that the WT+UV-B group was lower than the WT group,the fas1+UV-B group was lower than the fas1 group,the fas1+UV-B group was lower than the WT+UV-B group,the differences reached a significant level.In addition,under UV-B radiation conditions,it was observed that mitosis also showed some anomalies in the fas1+UV-B group.These results suggested that the loss of FAS1 gene function may be one of the incentives for fas1 mutants to be sensitive to UV-B stress.