摘要
芥子油苷是一类具有防御作用的植物次生代谢产物,外源激素茉莉酸对吲哚族芥子油苷的合成具有强烈的诱导作用,但茉莉酸调控吲哚族芥子油苷生物合成的分子机制并不清楚。以模式植物拟南芥(Arabidopsis thaliana)的野生型和coi1-22、coi1-23两种突变体为研究材料,通过茉莉酸甲酯(MeJA)处理,比较了拟南芥野生型和coi1突变体植株吲哚族芥子油苷含量、吲哚族芥子油苷合成前体色氨酸的生物合成基因(ASA1、TSA1和TSB1)、吲哚族芥子油苷生物合成基因(CYP79B2、CYP79B3和CYP83B1)及调控基因(MYB34和MYB51)的表达对MeJA的响应差异,由此确定茉莉酸信号通过COI1蛋白调控吲哚族芥子油苷生物合成,即茉莉酸信号通过信号开关COI1蛋白作用于转录因子MYB34和MYB51,进而调控吲哚族芥子油苷合成基因CYP79B2、CYP79B3、CYP83B1和前体色氨酸的合成基因ASA1、TSA1、TSB1。并且推断,COI1功能缺失后,茉莉酸信号可能通过其他未知调控因子或调控途径激活MYB34转录因子从而调控下游基因表达。
Glucosinolates are a group of sulphur-rich thioglucosides known to play an important role in plant defense. The accumulation of indolic glucosinolates （IGS） is strong induced by jasmonate （JA）. Many studies have demonstrated that coronatine-insensitive 1 （COI1） is important in JA signaling, and is involved in almost all the JA-responsive pathways. However, the underlying molecular mechanisms for JA-induced IGS accumulation remain partially understood. In this study, the coil-22 and coil-23 mutants and wild-type （WT） Arabidopsis thaliana plants were used to investigate the role of COI1 in MeJA-induced IGS metabolism.
The effect of MeJA treatment on IGS contents in coil-22 and coil-23 plants was analyzed. The results showed that the contents of IGS were significantly increased in MeJA-treated WT plants compared with the control, while the IGS levels were not changed notably in MeJA-treated coil-22 and coil-23 plants, indicating that the accumulation of IGS is insensitive to MeJA treatment in the mutants. Thus, coil-22 and coil-23 are good materials for studying the mechanisms of JA-induced IGS biosynthesis. Transcription factors are important regulators on the expression of genes. The R2R3-MYB transcription factors ATR1/MYB34 and HIG1/MYBS1 have been reported to act as the direct biosynthetic transcriptional activators for IGS, and they regulate many IGS biosynthetic genes and the tryptophan （IGS precursor） biosynthetic genes. The expression levels of MYB34 and MYB51 in MeJA-treated coil-22, coil-23 and WT plants were analyzed. The results showed that in WT plants, the expression levels of MYB34 and MYB51 were significantly higher in MeJA-treated plants than the control after 3 h MeJA-treatment, while it is not the case in coil-22 and coil-23 plants, indicating that the loss of function of COI1 blocks the MeJA-induced MYB34 and MYB51 expression. Furthermore, it is interesting to find that the expression levels of MYB34 in coil-22 and coil-23 mutants were significantly higher than in the contr
出处
《生态学报》
CAS
CSCD
北大核心
2012年第17期5438-5444,共7页
Acta Ecologica Sinica
基金
国家自然科学基金(31070351
30670325)
关键词
茉莉酸
COI1
吲哚族芥子油苷
拟南芥
jasmonic acid
COIl
indolic glucosinolate
Arabidopsis thaliana
