uv-b辐射对拟南芥芥子油苷代谢的影响.docx

摘要
摘要
芥子油苷(glucosinolates,GS)是十字花科(Crucifcrac)植物所含的一类含氮、含硫的次生代谢物。本文以模式植物拟南芥(Arabidopsis thaliana)为实验材料,观察了高强度UV-B辐射( mW/cm2)和随后的暗修复过程中莲座叶芥子油苷含量和相关基因表达模式的变化。
高强度UV-B辐射1 h后拟南芥莲座叶相对含水量和细胞膜透性基本没有改变,但 3 h后相对含水量下降、膜透性升高,持续照射12 h后损伤更为严重。随后经过12 h的暗恢复后,植株损伤在一定程度上得到缓解。
UV-B辐射的3 h内,编码转录因子的基因MYB5J『、OBP2、IQDI、MYB28和
觚8硒的表达上调,编码生物合成关键酶的基因MAM3、SOTl6和SOTl7的表达上调,主要的两种芥子油苷4MSOB和13M含量增加。但随着UV-B辐射对植株胁迫程度的加重,12 h后大部分代谢相关基因表达水平降低,芥子油苷总量降低。经过12 h暗修复后,一些基因(MYB34、CYP7983、SURJ、SOTl6、CYP81F2、MYB28、MAM3、
CYP79刃、)的转录水平恢复至或超过对照水平,芥子油苷总量恢复
至对照水平。
在UV-B辐射的初期和随后的暗修复过程中,JA和ET信号途径中几个关键基因(以刀、^∥C2、C鲫、AOC4、An豫川和A阳4)的表达有不同程度的上调,这可能意味着拟南芥在受到UV_B辐射后,通过体内JA和ET等信号途径参与调控芥子油苷及其它次生代谢物的生物合成,从而有助于缓解UV-B辐射对拟南芥造成的损伤。
关键词拟南芥;芥子油苷;UV-B辐射;基因表达
Abstract
Abstract
Glucosinolates(os)are nitrogen-and sulphur-containing secondary metabolites in
determined GS content and related gene expression in response to enhanced
WB radiation( 45 mW/cm2)and the eeding dark recovery process in model plant
Arabidopsis thaliana.
The result showed that there WaS no significant difference in relative water contents and membrane permeability of rosette leaves between the treatment and the control after l h of UV- B 3 h of Uv-B exposure,relative water contents decreaSed and membrane permeability with further UV-B exposure(12 h),the damage to membrane turned obviously 1 2 h of the eeding dark recovery,the damage caused by enhanced UV-B radiation could be partially recovered.
At the initial 3 h of enhanced UV-B radiation,UV-B signaling might trigger the increase of two main GS(4MSOB and 13M)contents in rosette leaves by activating the expression of several transcription factor genes(OBP2,MYBSI,1QDl,MYB28 and MrB76)and key genes involved in glucosinolate core structure biosynthesis(MAM3,SOTl 6 and SOTl 7).1 2 h of Uv- B exposure led to the downregulation of majority of GS metabolism related genes and GS total contents in 1 2 h of the eeding d