兰州大学机构库 >生命科学学院
低温胁迫下油菜素内酯调控拟南芥果胶去甲基酯化的研究
Alternative TitleStudy of demethylesterification of pectin, regulated by Brassinosteroids in Arabidopsis under chilling stress
曲涛
Thesis Advisor安黎哲
2011-11-26
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword拟南芥 低温胁迫 果胶甲基酯酶 油菜素内酯
Abstract1、揭示了油菜素内酯对果胶甲基酯酶活性具有正调控作用。外源施加1μM eBL能够诱导果胶甲基酯酶活性持续升高,在处理12小时时达到峰值。 2、阐明了低温诱导的果胶甲基酯酶活性增加依赖于油菜素内酯信号途径。研究表明,低温胁迫能够诱导拟南芥野生型和油菜素内酯信号持续激活突变体bzr1-1D幼苗中果胶甲基酯酶活性增加,低温不但不能诱导油菜素内酯受体激酶BRI1的无功能突变体bri1-116中果胶甲基酯酶活性增加,反而引起酶活性降低。 3、证明了低温诱导的果胶甲基酯酶基因AtPME41的表达依赖于油菜素内酯信号通路。半定量PCR分析证实AtPME41 mRNA水平受冷胁迫和油菜素内酯处理上调,但是冷胁迫不能上调bri1-116中AtPME41的表达。并且低温胁迫诱导的AtPME41转录物峰值的出现时间(6小时)较eBL诱导的峰值的出现时间(3小时)晚。 4、揭示了AtPME41基因的表达和油菜素内酯在低温胁迫下的生理意义。相对于野生型,低温导致pme41和 bri1-116细胞膜通透性显著升高,低温也导致了野生型和bri1-116膜脂过氧化程度明显升高。但低温处理前后Col-0和pme41中MDA的含量和变化趋势没有明显差别。这些结果表明油菜素内酯信号的缺失能显著降低了拟南芥对低温的耐受。果胶甲基酯酶活性的减少导致细胞膜通透性增加,但没有引起MDA含量的积累,说明果胶甲基酯酶对细胞膜具有保护作用。 5、证实了低温胁迫能够增强油菜素内酯信号的转导。通过对油菜素内酯分子标记BZR1的磷酸化状态分析,证明低温胁迫能够增加并且是通过油菜素内酯受体BRI途径增加油菜素内酯信号的转导。 6、发现了一氧化氮与油菜素内酯的互作关系。通过对BZR1的磷酸化状态分析,证明一氧化氮作用在油菜素内酯信号通路的下游或者与油菜素内酯的作用是平行的。 总之,研究结果表明拟南芥中低温胁迫调控果胶甲基酯酶的表达和活性升高是依赖油菜素内酯信号通路的,并且可能主要通过油菜素内酯调控AtPME41的表达实现。果胶甲基酯酶活性的减少增加了拟南芥在低温胁迫下的细胞膜通透性,说明果胶甲基酯酶对细胞膜具有重要的保护作用。低温胁迫可以增强油菜素内酯信号的转导,油菜素内酯信号的缺失大大降低了拟南芥对低温胁迫的耐受,说明油菜素内酯在植物低温胁迫中具有重要的生理意义。
Other AbstractPlant cell wall plays important 1、Exogenous eBL treatments had a positive effect on enhancing PME activity. PME activity induced by exposing 1μM eBL continued to increase and reached a peak after 12 hours of eBL treatment.. 2、Chilling-induced increase in PME activity depends on BR signaling pathway. In our studies, PME activity increased under chilling stress in seedlings of Arabidopsis and bzr1-1D, a constitutive BR signaling activation mutant. Chilling-stress stimulation of PME activity not only was not found in bri1-116 mutant, a null allele of BR receptor kinase BRI1, but also resulted in decrease of PME activity. 3、Chilling-induced expression of AtPME41 depends on BR signaling pathway. Semi-quantitative RT-PCR analysis confirmed that AtPME41 was up-regulated by BR. Our results of RT-PCR analysis also showed that the expression of AtPME41 was up-regulated by chilling stress, but this effect was impaired in bri1-116. It was worth noticing that the peak of AtPME41 transcripts induced by chilling treatment (6 hours) was later than by eBL treatment (3 hours). 4、Our studies showed the physiological means of AtPME41 expression and brassinosteroids during cold acclimation. Chilling stress resulted in significant increases in ion leakage in pme41 and bri1-116, compare with wild type. Low temperature treatment also led to obvious increases in extent of lipid peroxidation in wide type and bri1-116. But the changes of MDA content in col-0 and pme41 showed the same trend before and after chilling treatment. These results suggested that decrease of BR singaling significantly decreased chilling telorance in Arabidopsis. Meanwhile, decrease of PME activity lead to increase in ion leakage, but not caused accumulation of MDA content, implying the protection of PME to cell member. 5、Chilling stress induced BR signaling output. By analyzing the phosphorylation states of BR bio-marker BZR1, our results showed that chilling stress induced BR signaling output through BR receptor BRI1pathway 6、Our studies showed the relationship between NO and BR. NO acted downstream of, or at the same level as BR signaling pathway by analyzing the phosphorylation states of BR bio-marker BZR1. In conclusion, our results indicated that chilling stress regulation of PMEs in Arabidopsis was BR dependent, probably by regulating the expression of AtPME41. The decrease of PME activity increased ion leakage in the seedling of Arabidopsis under chilling stress. This result suggested the ...
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Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/221554
Collection生命科学学院
Recommended Citation
GB/T 7714
曲涛. 低温胁迫下油菜素内酯调控拟南芥果胶去甲基酯化的研究[D]. 兰州. 兰州大学,2011.
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