|Alternative Title||Study of demethylesterification of pectin， regulated by Brassinosteroids in Arabidopsis under chilling stress
|Place of Conferral||兰州
|Other Abstract||Plant 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 ...|
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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