Abiotic Stresses Induce Heat Shock Factors to Regulate Small Heat Shock Protein Genes Expression in Arabidopsis thaliana
Date Issued
2007
Date
2007
Author(s)
Huang, Tsung-Chih
DOI
en-US
Abstract
Heat stress is one of the major environmental stresses. When plants are exposed in the elevated temperature, a general physiological process called heat shock (HS) response makes plants accumulate amounts of proteins called heat shock proteins (HSPs) to survive from heat stress. Among HSPs, small HSPs (sHSP) represent the unusual abundance and complexity in plants, and are mainly regulated by heat shock factors (HSFs). There are 21 HSFs in Arabidopsis in compared with 4 in mammalian, but the roles of each HSF in controlling sHSP gene expression and thermotolerance remain largely unaddressed. Hence, this study used reverse genetics analysis to clarify the roles of these HSFs in Arabidopsis. We screened 11 AtHSFs T-DNA insertion lines and 8 AtHSFs null mutant lines including AthsfA1e, AthsfA2, AthsfA4c, AthsfA5, AthsfA6a, AthsfA7a, AthsfA7b, and AthsfB2b were characterized and confirmed by RT-PCR. Through microarray database mining and RT-PCR analysis, some HSFs were induced by certain abiotic stresses. When HSF knock-out plants were treated with various abiotic stresses to examine sHSPs expression, the experiment results confirmed that under heavy metals treatments several sHSPs expression in AthsfA7a mutants was affected, and in AthsfA6a mutant sHSPs expression were also interfered during salt and osmotic stresses. Hence, AtHSFA7a and AtHSFA6a may regulate sHSPs expressions respectively in response to heavy metal and osmotic or salt stresses. When testing the thermotolerance in each HSF null mutant plants, results showed they didn’t lose the basal and acquired thermotolerance, except in AthsfA2. In summary, the expression profile of sHSPs and HSFs under HS and other abiotic stress as well as the regulation of sHSPs expression by several HSFs are established. In addition, AtHSFA7a and AtHSFA6a specifically functioning in regulation of sHSPs expressions in response to heavy metal and osmotic or salt stresses are suggested.
Subjects
熱休克轉錄因子
低分子量熱休克蛋白
熱逆境
heat shock
heat shock factors
small heat shock proteins
Type
other
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