中文摘要：

At J8是拟南芥J-蛋白家族成员。已有报道,At J8定位于叶绿体中,参与光合作用的调节。该文主要研究At J8在适应盐和水分胁迫方面的作用。实时定量PCR结果表明,盐、水分胁迫及脱落酸（abscisic acid,ABA）诱导At J8基因的表达。反向遗传学研究显示,在正常生长条件下,At J8突变体（atj8-1）的种子萌发率及绿色子叶出现率与野生型（WT）和突变体恢复株系（R4-1）没有明显差别;在盐和水分胁迫条件下,atj8-1种子萌发延迟,绿色子叶出现率明显低于WT和R4-1株系,表明At J8可能在调节种子及幼苗对渗透胁迫的适应性方面发挥重要作用。此外,实时定量PCR结果显示,At J8基因突变改变了ABA反应基因ABI1、ABI2、RAB18、RD29A和RD29B的表达,说明At J8调节植物对渗透胁迫的适应性可能是通过影响ABA信号途径来完成的。

英文摘要：

At J8 is a member of the Arabidopsis thaliana J-protein family. It is reported that At J8 is targeted to the chloroplast and involved in optimization of photosynthetic reactions in A. thaliana. Herein, the roles of At J8 in adapting to saline and water stresses were studied in A. thaliana. The result of Real-time PCR analysis showed that At J8 expression was induced through salinity, dehydration and abscisic acid（ABA） in young seedlings. The result of reverse genetic analysis showed that seed germination rate and cotyledon greening rate of At J8 mutant plants（atj8-1） were not clearly different from those of wild-type（WT） and the rescued mutant plants（R4-1） under standard culture conditions. However, under saline or water stress condition, atj8-1 seeds broke dormancy after the WT and R4-1 seeds, and cotyledon greening rate for atj8-1 seedlings was clearly lower than that for the WT and R4-1 seedlings, which suggested that At J8 played important roles in regulating the responses of seeds and seedlings to osmotic stress. Moreover, Real-time PCR analysis indicated that At J8 gene knockout altered the expression levels of several ABA-responsive genes, ABI1, ABI2, RAB18, RD29 A and RD29 B, which suggested that At J8 modulated the adaptability of plants to osmotic stress likely through its effects on ABA signaling pathways.