The expression of Arabidopsis PDF1.2 gene is regulated by jasmonic acid (JA) and ethylene (ET). It also has been well documented that GCC box is an element re- sponsive to ET,however, the responsive mechanism of JA in...The expression of Arabidopsis PDF1.2 gene is regulated by jasmonic acid (JA) and ethylene (ET). It also has been well documented that GCC box is an element re- sponsive to ET,however, the responsive mechanism of JA in such plant defense gene expression is unclear. In this paper, the authors define the essential cis-acting element in PDF1.2 promoter responsive to methyl jasmonate (MeJA) through fragment deletions and site-directed mutageneses combining Agrobacterium-mediated transient reporter gene expression in tobacco leaves. Firstly, the MeJA inducible expression of PDF1.2 was confirmed by using the upstream ?1.86 kb fragment of PDF1.2 gene. Secondly, the upstream –300— ?243 bp fragment of the promoter was evidenced to respond to MeJA. To further characterize this promoter region, three point mutations were introduced into the –300—?243 bp fragment of the promoter. This result showed that the muta- tion of GCC box abolished MeJA induction, whereas the mutations of the G box-like and the imperfect palindrome sequence did not significantly decrease MeJA inducible effect, indicating that GCC box in PDF1.2 is essential for MeJA induction. The sufficient responsiveness to MeJA of this GCC box was further investigated by 4×GCC fused up- stream to the CaMV 35S minimal promoter. This result sug- gested that the fused promoter was able to activate reporter gene expression in response to MeJA. Thus these results in- dicate that the GCC box in PDF1.2 is an essential and suffi- cient element to confer MeJA induction.展开更多
TaPHT1.2 is a functional, root predominantly expressed and low phosphate （Pi） inducible high-affinity Pi transporter in wheat, which is more abundant in the roots of P-efficient wheat genotypes （e.g., Xiaoyan 54） ...TaPHT1.2 is a functional, root predominantly expressed and low phosphate （Pi） inducible high-affinity Pi transporter in wheat, which is more abundant in the roots of P-efficient wheat genotypes （e.g., Xiaoyan 54） than in P-inefficient genotypes （e.g., Jing 411） under both Pi-deficient and Pi-sufficient conditions. To characterize TaPHT1.2 further, we genetically mapped a TaPHT1.2 transporter, TaPHT1.2-D1, on the long arm of chromosome 4D using a recombinant inbred line population derived from Xiaoyan 54 and Jing 411, and isolated a 1,302 bp fragment of the TaPHT1.2-D1 promoter （PrTaPHT1.2-D1） from Xiaoyan 54. TaPHT1.2-D1 shows collinearity with OsPHT1.2 that has previously been reported to mediate the translocation of Pi from roots to shoots. PrTaPHT1.2-D contains a number of Pi-starvation responsive elements, including P1BS, WRKY-binding W-box, and helix-loop-helix-binding elements. PrTaPHT1.2-D1 was then used to drive expression of 13-glucuronidase （GUS） reporter gene in Arabidopsis through Agrobacterium-mediated transformation. Histochemical analysis of transgenic Arabidopsis plants showed that the reporter gene was specifically induced by Pi-starvation and predominantly expressed in the roots. As there is only one SNP between the TaPHT1.2-D1 promoters of Xiaoyan 54 and Jing 411, and this SNP does not exist within the Pi-starvation responsive elements, the differential expression of TaPHT1.2 in Xiaoyan 54 and Jing 411 may not be caused by this SNP.展开更多
文摘The expression of Arabidopsis PDF1.2 gene is regulated by jasmonic acid (JA) and ethylene (ET). It also has been well documented that GCC box is an element re- sponsive to ET,however, the responsive mechanism of JA in such plant defense gene expression is unclear. In this paper, the authors define the essential cis-acting element in PDF1.2 promoter responsive to methyl jasmonate (MeJA) through fragment deletions and site-directed mutageneses combining Agrobacterium-mediated transient reporter gene expression in tobacco leaves. Firstly, the MeJA inducible expression of PDF1.2 was confirmed by using the upstream ?1.86 kb fragment of PDF1.2 gene. Secondly, the upstream –300— ?243 bp fragment of the promoter was evidenced to respond to MeJA. To further characterize this promoter region, three point mutations were introduced into the –300—?243 bp fragment of the promoter. This result showed that the muta- tion of GCC box abolished MeJA induction, whereas the mutations of the G box-like and the imperfect palindrome sequence did not significantly decrease MeJA inducible effect, indicating that GCC box in PDF1.2 is essential for MeJA induction. The sufficient responsiveness to MeJA of this GCC box was further investigated by 4×GCC fused up- stream to the CaMV 35S minimal promoter. This result sug- gested that the fused promoter was able to activate reporter gene expression in response to MeJA. Thus these results in- dicate that the GCC box in PDF1.2 is an essential and suffi- cient element to confer MeJA induction.
基金supported by the Ministry of Science and Technology of China (No.2005CB120904 and 2006AA10A105)the National Natural Science Foundation of China (No.30890133 and 30521001)the Chinese Academy of Sciences (No.KSCX2-YW-N-001)
文摘TaPHT1.2 is a functional, root predominantly expressed and low phosphate （Pi） inducible high-affinity Pi transporter in wheat, which is more abundant in the roots of P-efficient wheat genotypes （e.g., Xiaoyan 54） than in P-inefficient genotypes （e.g., Jing 411） under both Pi-deficient and Pi-sufficient conditions. To characterize TaPHT1.2 further, we genetically mapped a TaPHT1.2 transporter, TaPHT1.2-D1, on the long arm of chromosome 4D using a recombinant inbred line population derived from Xiaoyan 54 and Jing 411, and isolated a 1,302 bp fragment of the TaPHT1.2-D1 promoter （PrTaPHT1.2-D1） from Xiaoyan 54. TaPHT1.2-D1 shows collinearity with OsPHT1.2 that has previously been reported to mediate the translocation of Pi from roots to shoots. PrTaPHT1.2-D contains a number of Pi-starvation responsive elements, including P1BS, WRKY-binding W-box, and helix-loop-helix-binding elements. PrTaPHT1.2-D1 was then used to drive expression of 13-glucuronidase （GUS） reporter gene in Arabidopsis through Agrobacterium-mediated transformation. Histochemical analysis of transgenic Arabidopsis plants showed that the reporter gene was specifically induced by Pi-starvation and predominantly expressed in the roots. As there is only one SNP between the TaPHT1.2-D1 promoters of Xiaoyan 54 and Jing 411, and this SNP does not exist within the Pi-starvation responsive elements, the differential expression of TaPHT1.2 in Xiaoyan 54 and Jing 411 may not be caused by this SNP.
