MicroRNAs （miRNAs） are derived from distinct loci in the genome and play crucial roles in RNA-mediated gene silencing mechanisms that regulate cellular processes during development and stress responses of plants. Th...MicroRNAs （miRNAs） are derived from distinct loci in the genome and play crucial roles in RNA-mediated gene silencing mechanisms that regulate cellular processes during development and stress responses of plants. The miRNAs are approximately 21 nucleotides long and code for the complementary strand to a larger genic mRNA. They are often found within the complementary primary transcript （pri-miRNAs）. In the past few years, a growing number of soybean miRNAs have been discovered, however, little is known about the transcriptional regulation of these miRNAs. In this study, promoters and cis-acting elements of soybean miRNAs were analyzed using the genomic data for the first time. A total of 82 miRNAs were located among 122 loci in genome, some were present as double or multiple copies. Five clusters that included ten miRNAs were found in genome, and only one cluster share the same promoter. A total of 191 promoters from 122 loci of the soybean miRNA sequences were found and further analyzed. The results indicated that the conserved soybean miRNA genes had a greater proportion of promoters than that of non-conserved ones, and the distribution of the transcript start sites （TSSs） and TATA-boxes found had different motif styles between conserved and non-conserved miRNA genes. Furthermore, the cis-acting elements 5＇ of the TSSs were analyzed to obtain potential function and spatiotemporal expression pattern of miRNAs. The data obtained here may lead to the identification of specific sequences upstream of pre-miRNAs and the functional annotation of miRNAs in soybean.展开更多
Previous study has defined DRE (dehydration responsive element) cis acting element and its important role in expressions of Arabidopsis rd29A gene under cold, dehydration and high salt stresses. In order to...Previous study has defined DRE (dehydration responsive element) cis acting element and its important role in expressions of Arabidopsis rd29A gene under cold, dehydration and high salt stresses. In order to clarify the expression mechanism of rd29A gene, we isolated two cDNA clones that encoded DRE binding proteins ( DREB1 and DREB2 ) from cold and drought treated Arabidopsis plants, using DRE cis acting element in the promoter region of rd29A gene and yeast One Hybrid screening method. Experiments showed both DREB1 and DREB2 specifically interacted with DRE cis element. Homologous analysis showed no significant similarity between DREB1 and DREB2 in whole deduced amino acid sequences. However, both DREB1 and DREB2 proteins contained a conserved DNA binding domain (AP2/EREBP domain). Structural analysis of proteins also showed they had a nuclear localization signal (NLS) in their N terminal region and an acidic activation region in their C terminal region. AP2/EREBP domain is composed of 58 amino acids, which presents in a large family of plant genes encoding DNA binding proteins. We analyzed many plant transcription factors containing conserved AP2/EREBP domains. The 14th valine (V) and 19th glutamate (E) in the amino acid sequence of AP2/EREBP domains might be the consensus recognizing and binding to DRE cis element. Northern analysis indicated that DREB1 gene was induced by low temperature, whereas DREB2 gene was induced by dehydration and high salt stresses. Present studies suggest that the expression of rd29A gene under low temperature, dehydration and high salt stresses is regulated by DREB1 and DREB2 transcriptional factors in two separate signal transduction pathways, respectively.展开更多
A 5＇ flanking region of the well-conserved Toll/interleukin-1 receptor domain （TIR）-encoding sequence was isolated from the genomic DNA ofMelampsora magnusiana Wagner resistant clones of hybrid triploid poplars [（...A 5＇ flanking region of the well-conserved Toll/interleukin-1 receptor domain （TIR）-encoding sequence was isolated from the genomic DNA ofMelampsora magnusiana Wagner resistant clones of hybrid triploid poplars [（Populus tomentosa × P. bolleana） × P. tomentosa]. Sequencing results and alignment analysis show that the obtained TIR-specific promoter （named as PtTIRp01） was 1,732 bp in length; moreover 3＇ region of the PtTIRp01 contains a responds to the 5＇ composition of TIR-NBS type gene PtDRG02, of 747 bp long 5＇ region of TIR-NBS type gene PtDRG02 and its 398 bp complete TIR-encoding sequence, which significantly corindicating that the obtained TIR-specific promoter region consists upstream region of promoter （985 bp）. It was found that the 5＇ region of TIR-NBS type gene PtDRG02 was characterized in the downstream region of the transcriptional start, named as 5＇-untranslated region （5＇ UTR）, consisting of one 93 bp 5＇-untranslation exon, one 213 bp intron and one 441 bp TIR-encoding open reading frame （ORF）. In addition, several putative cis-acting motifs were present in the obtained TIR-specific promoter of PtDRG02, including one TATA box, one GC-rich, one AT-rich, one P-box, one 3-AF1 binding site, two CAAT boxes, two GT-1 motifs, three typical W-boxes, four I-boxes, and one multi-cis-acting fragment （MCF）. The latter contains five types of regulatory elements （E4, G-box, ABRE motif, box 1 and HVA 1 s）, most of which were homologous to the cis-acting regulatory elements involved in the activation of defense genes in plants. Thus, it can be suggested that TIR-specific promoter might be a pathogen-inducible promoter and be necessary for the inducible expression of defense-related genes. Key words Toll/interleukin- 1 receptor domain, promoter, Cis-acting element, poplar展开更多
The cis-acting regulatory elements, e.g., promoters and ribosome binding sites （RBSs） with various desired properties, are building blocks widely used in synthetic biology for fine tuning gene expression. In the las...The cis-acting regulatory elements, e.g., promoters and ribosome binding sites （RBSs） with various desired properties, are building blocks widely used in synthetic biology for fine tuning gene expression. In the last decade, acquisition of a controllable regulatory element from a random library has been established and applied to control the protein expression and metabolic flux in different chassis cells. However, more rational strategies are still urgently needed to improve the efficiency and reduce the laborious screening and multifaceted characterizations. Building precise computational models that can predict the activity of regulatory elements and quantitatively design elements with desired strength have been demonstrated tremendous potentiality. Here, recent progress on construction of cis- acting regulatory element library and the quantitative predicting models for design of such elements are reviewed and discussed in detail.展开更多
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
The importance of microRNA （miRNA） at the post-transcriptional regulation level has recently been recognized in both animals and plants. In recent years, many studies focused on miRNA target identification and funct...The importance of microRNA （miRNA） at the post-transcriptional regulation level has recently been recognized in both animals and plants. In recent years, many studies focused on miRNA target identification and functional analysis. However, little is known about the transcription and regulation of miRNAs themselves. In this study, the transcription start sites （TSSs） for 11 miRNA primary transcripts of soybean from 11 miRNA loci （of 50 loci tested） were cloned by a 5＂ rapid amplification of cDNA ends （5＂ RACE） procedure using total RNA from 30-d-old seedlings. The features consistent with a RNA polymerase II mechanism of transcription were found among these miRNA loci. A position weight matrix algorithm was used to identify conserved motifs in miRNA core promoter regions. A canonical TATA box motif was identified upstream of the major start site at 8 （76%） of the mapped miRNA loci. Several cis-acting elements were predicted in the 2 kb 5＂ to the TSSs. Potential spatial and temporal expression patterns of the miRNAs were found. The target genes for these miRNAs were also predicted and further elucidated for the potential function of the miRNAs. This research provides a molecular basis to explore regulatory mechanisms of miRNA expression, and a way to understand miRNA-mediated regulatory pathways and networks in soybean.展开更多
Our previous studies have revealed that the Th CAP gene plays a vital role in transgenic Populus(P.davidiana 9 P.bolleana) in response to cold stress.However,the regulatory mechanism of Th CAP gene expression has been...Our previous studies have revealed that the Th CAP gene plays a vital role in transgenic Populus(P.davidiana 9 P.bolleana) in response to cold stress.However,the regulatory mechanism of Th CAP gene expression has been unclear.In this study,the 50 flanking region of the Th CAP promoter(PTh CAP) was cloned using a genomewalking method.By analyzing cis-acting regulatory elements of PTh CAP,a DRE motif and MYC and MYB elements were found to be located in the promoter.To identify the regulatory elements that control the expression of the Th CAP gene promoter,a series of deletion derivatives ofPTh CAP,P1–P5,from the translation start code(-1538,-1190,-900,-718 and-375 bp),were fused to the GUS reporter gene,and then each deletion was stably introduced into Arabidopsis thaliana plants.Deletion analysis of the promoter suggested that only the P2 fragment had strong GUS expression in leaves and roots of A.thaliana exposed to low temperature stress.These results suggest that this290-bp region(-1190 to-900 bp),as an important part in PTh CAP,was associated with cold tolerance of A.thaliana.Our results provide evidence for the regulatory mechanism of Th CAP gene involved in the response to cold stress,and that the gene is promising candidate gene for genetic improvement of crops.展开更多
Two different length fragments, RSF1 and RSF2 which contained the cis-acting sequences of root-specific gene TobRB7, were isolated from tobacco genome. The abilities of these fragments to direct root-specific expressi...Two different length fragments, RSF1 and RSF2 which contained the cis-acting sequences of root-specific gene TobRB7, were isolated from tobacco genome. The abilities of these fragments to direct root-specific expression were studied by fusing them to the β-glucuronidase (GUS) report gene with different directions. After the recombined vectors were transformed into tobacco, the expression pattern was performed by histochemical staining and the quantitative analysis of GUS activity. The data suggested that the cis-acting element of TobRB7 gene direct GUS expression not only as root-specific but also as bidirectional. In our studies, the short fragment, RSF2, performed stronger activity than RSF1 with any direction. The stronger activity of GUS expression was determined by reverse inserting of RSF1 or RSF2 than positive inserting.展开更多
The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-...The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-8th weeks of gestation. Recently, several studieson the transgenic mice have shown that the 5′-flanking DNA sequences of human展开更多
Aquaporins are ubiquitous channel proteins that facilitate the transport of water across cell membranes. Most of aquaporins are represent in more than one tissues, but some of them performed highest in roots. They are...Aquaporins are ubiquitous channel proteins that facilitate the transport of water across cell membranes. Most of aquaporins are represent in more than one tissues, but some of them performed highest in roots. They are be- lived to participate in water transport. DcRB7, a member of the aquaporin family, was isolated from somatic embryos of carrot and identified as a homologous gene of TobRB7. Further studies showed that the expression of DcRB7 was particular in carrot root. To investigate the transcription regulation of DcRB7, a 650-bp upstream sequence of DcRB7 was isolated by inverse PCR, and was fused to the β-glucuronidase (GUS) report gene. After the recombined vectors were transformed into tobacco, the expression pat- tern was performed by histochemical staining and the quan- titative analysis of GUS activity. The results indicated that the cis-acting element of DcRB7 gene directs GUS expression not only as root-specific but also as drought inducible.展开更多
基金supported by the National High-Tech R&D Program of China (863 Program,2006AA100104-4)the Project of 948 from Ministryof Agriculture of China (2006-G5)+5 种基金the National Nature Science Foundation of China (30971810,60932008)the National Basic Research Program ofChina (973 Program, 2009CB118400)the Postdoctoral Fund in Heilongjiang Province, China (LBH-Z07228)the Foundation Projects of Northeast Agricultural University, Chinathe Technology Project of Education Ministry of Heilongjiang Province, China(11541025)the Technology Project of Harbin,China (2009RFQXN085)
文摘MicroRNAs （miRNAs） are derived from distinct loci in the genome and play crucial roles in RNA-mediated gene silencing mechanisms that regulate cellular processes during development and stress responses of plants. The miRNAs are approximately 21 nucleotides long and code for the complementary strand to a larger genic mRNA. They are often found within the complementary primary transcript （pri-miRNAs）. In the past few years, a growing number of soybean miRNAs have been discovered, however, little is known about the transcriptional regulation of these miRNAs. In this study, promoters and cis-acting elements of soybean miRNAs were analyzed using the genomic data for the first time. A total of 82 miRNAs were located among 122 loci in genome, some were present as double or multiple copies. Five clusters that included ten miRNAs were found in genome, and only one cluster share the same promoter. A total of 191 promoters from 122 loci of the soybean miRNA sequences were found and further analyzed. The results indicated that the conserved soybean miRNA genes had a greater proportion of promoters than that of non-conserved ones, and the distribution of the transcript start sites （TSSs） and TATA-boxes found had different motif styles between conserved and non-conserved miRNA genes. Furthermore, the cis-acting elements 5＇ of the TSSs were analyzed to obtain potential function and spatiotemporal expression pattern of miRNAs. The data obtained here may lead to the identification of specific sequences upstream of pre-miRNAs and the functional annotation of miRNAs in soybean.
基金the National Natural Science Foun dation of China! (No .396 70 40 8)
文摘Previous study has defined DRE (dehydration responsive element) cis acting element and its important role in expressions of Arabidopsis rd29A gene under cold, dehydration and high salt stresses. In order to clarify the expression mechanism of rd29A gene, we isolated two cDNA clones that encoded DRE binding proteins ( DREB1 and DREB2 ) from cold and drought treated Arabidopsis plants, using DRE cis acting element in the promoter region of rd29A gene and yeast One Hybrid screening method. Experiments showed both DREB1 and DREB2 specifically interacted with DRE cis element. Homologous analysis showed no significant similarity between DREB1 and DREB2 in whole deduced amino acid sequences. However, both DREB1 and DREB2 proteins contained a conserved DNA binding domain (AP2/EREBP domain). Structural analysis of proteins also showed they had a nuclear localization signal (NLS) in their N terminal region and an acidic activation region in their C terminal region. AP2/EREBP domain is composed of 58 amino acids, which presents in a large family of plant genes encoding DNA binding proteins. We analyzed many plant transcription factors containing conserved AP2/EREBP domains. The 14th valine (V) and 19th glutamate (E) in the amino acid sequence of AP2/EREBP domains might be the consensus recognizing and binding to DRE cis element. Northern analysis indicated that DREB1 gene was induced by low temperature, whereas DREB2 gene was induced by dehydration and high salt stresses. Present studies suggest that the expression of rd29A gene under low temperature, dehydration and high salt stresses is regulated by DREB1 and DREB2 transcriptional factors in two separate signal transduction pathways, respectively.
文摘A 5＇ flanking region of the well-conserved Toll/interleukin-1 receptor domain （TIR）-encoding sequence was isolated from the genomic DNA ofMelampsora magnusiana Wagner resistant clones of hybrid triploid poplars [（Populus tomentosa × P. bolleana） × P. tomentosa]. Sequencing results and alignment analysis show that the obtained TIR-specific promoter （named as PtTIRp01） was 1,732 bp in length; moreover 3＇ region of the PtTIRp01 contains a responds to the 5＇ composition of TIR-NBS type gene PtDRG02, of 747 bp long 5＇ region of TIR-NBS type gene PtDRG02 and its 398 bp complete TIR-encoding sequence, which significantly corindicating that the obtained TIR-specific promoter region consists upstream region of promoter （985 bp）. It was found that the 5＇ region of TIR-NBS type gene PtDRG02 was characterized in the downstream region of the transcriptional start, named as 5＇-untranslated region （5＇ UTR）, consisting of one 93 bp 5＇-untranslation exon, one 213 bp intron and one 441 bp TIR-encoding open reading frame （ORF）. In addition, several putative cis-acting motifs were present in the obtained TIR-specific promoter of PtDRG02, including one TATA box, one GC-rich, one AT-rich, one P-box, one 3-AF1 binding site, two CAAT boxes, two GT-1 motifs, three typical W-boxes, four I-boxes, and one multi-cis-acting fragment （MCF）. The latter contains five types of regulatory elements （E4, G-box, ABRE motif, box 1 and HVA 1 s）, most of which were homologous to the cis-acting regulatory elements involved in the activation of defense genes in plants. Thus, it can be suggested that TIR-specific promoter might be a pathogen-inducible promoter and be necessary for the inducible expression of defense-related genes. Key words Toll/interleukin- 1 receptor domain, promoter, Cis-acting element, poplar
基金This work was supported by the National Basic Research Program of China （973 Program, grant No. 2012CB721104）, the National High Technology Research and Development Program （863 Program, grant No. 2012AA02A701）, the National Natural Science Foundation of China （grant Nos. 31170101 and 31301017）, and the Natural Science Foundation of Guangdong Province, China （grant No. 2015A030310317）.
文摘The cis-acting regulatory elements, e.g., promoters and ribosome binding sites （RBSs） with various desired properties, are building blocks widely used in synthetic biology for fine tuning gene expression. In the last decade, acquisition of a controllable regulatory element from a random library has been established and applied to control the protein expression and metabolic flux in different chassis cells. However, more rational strategies are still urgently needed to improve the efficiency and reduce the laborious screening and multifaceted characterizations. Building precise computational models that can predict the activity of regulatory elements and quantitatively design elements with desired strength have been demonstrated tremendous potentiality. Here, recent progress on construction of cis- acting regulatory element library and the quantitative predicting models for design of such elements are reviewed and discussed in detail.
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 National High-Tech R&D Program of China (2006AA10Z1F1)the National Core Soybean Genetic Engineering Project, China(2011ZX08004-002)+3 种基金the National Natural Science Foundation of China (60932008, 30971810)the National Basic Research Program of China (2009CB118400)the Ministry of Education Innovation Team of Soybean Molecular Design,Chinathe Innovation Team of the Education Bureau of Heilongjiang Province, China
文摘The importance of microRNA （miRNA） at the post-transcriptional regulation level has recently been recognized in both animals and plants. In recent years, many studies focused on miRNA target identification and functional analysis. However, little is known about the transcription and regulation of miRNAs themselves. In this study, the transcription start sites （TSSs） for 11 miRNA primary transcripts of soybean from 11 miRNA loci （of 50 loci tested） were cloned by a 5＂ rapid amplification of cDNA ends （5＂ RACE） procedure using total RNA from 30-d-old seedlings. The features consistent with a RNA polymerase II mechanism of transcription were found among these miRNA loci. A position weight matrix algorithm was used to identify conserved motifs in miRNA core promoter regions. A canonical TATA box motif was identified upstream of the major start site at 8 （76%） of the mapped miRNA loci. Several cis-acting elements were predicted in the 2 kb 5＂ to the TSSs. Potential spatial and temporal expression patterns of the miRNAs were found. The target genes for these miRNAs were also predicted and further elucidated for the potential function of the miRNAs. This research provides a molecular basis to explore regulatory mechanisms of miRNA expression, and a way to understand miRNA-mediated regulatory pathways and networks in soybean.
基金supported by the State Key Laboratory of Tree Genetics and Breeding(Northeast Forestry University)(201102)Natural Science Foundation of Heilongjiang Province(QC2012C057)+2 种基金China Postdoctoral Science Foundation(2013M531005)Foundation for the Postdoctoral of Heilongjiang Province(LBH-Z12007)National Natural Science Foundation of China(31200510)
文摘Our previous studies have revealed that the Th CAP gene plays a vital role in transgenic Populus(P.davidiana 9 P.bolleana) in response to cold stress.However,the regulatory mechanism of Th CAP gene expression has been unclear.In this study,the 50 flanking region of the Th CAP promoter(PTh CAP) was cloned using a genomewalking method.By analyzing cis-acting regulatory elements of PTh CAP,a DRE motif and MYC and MYB elements were found to be located in the promoter.To identify the regulatory elements that control the expression of the Th CAP gene promoter,a series of deletion derivatives ofPTh CAP,P1–P5,from the translation start code(-1538,-1190,-900,-718 and-375 bp),were fused to the GUS reporter gene,and then each deletion was stably introduced into Arabidopsis thaliana plants.Deletion analysis of the promoter suggested that only the P2 fragment had strong GUS expression in leaves and roots of A.thaliana exposed to low temperature stress.These results suggest that this290-bp region(-1190 to-900 bp),as an important part in PTh CAP,was associated with cold tolerance of A.thaliana.Our results provide evidence for the regulatory mechanism of Th CAP gene involved in the response to cold stress,and that the gene is promising candidate gene for genetic improvement of crops.
文摘Two different length fragments, RSF1 and RSF2 which contained the cis-acting sequences of root-specific gene TobRB7, were isolated from tobacco genome. The abilities of these fragments to direct root-specific expression were studied by fusing them to the β-glucuronidase (GUS) report gene with different directions. After the recombined vectors were transformed into tobacco, the expression pattern was performed by histochemical staining and the quantitative analysis of GUS activity. The data suggested that the cis-acting element of TobRB7 gene direct GUS expression not only as root-specific but also as bidirectional. In our studies, the short fragment, RSF2, performed stronger activity than RSF1 with any direction. The stronger activity of GUS expression was determined by reverse inserting of RSF1 or RSF2 than positive inserting.
基金Project supported by grants from Shanghai Joint Laboratory of Life Sciences, the Chinese Academy of Sciences, and the National Natural Science Foundation of China.
文摘The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-8th weeks of gestation. Recently, several studieson the transgenic mice have shown that the 5′-flanking DNA sequences of human
文摘Aquaporins are ubiquitous channel proteins that facilitate the transport of water across cell membranes. Most of aquaporins are represent in more than one tissues, but some of them performed highest in roots. They are be- lived to participate in water transport. DcRB7, a member of the aquaporin family, was isolated from somatic embryos of carrot and identified as a homologous gene of TobRB7. Further studies showed that the expression of DcRB7 was particular in carrot root. To investigate the transcription regulation of DcRB7, a 650-bp upstream sequence of DcRB7 was isolated by inverse PCR, and was fused to the β-glucuronidase (GUS) report gene. After the recombined vectors were transformed into tobacco, the expression pat- tern was performed by histochemical staining and the quan- titative analysis of GUS activity. The results indicated that the cis-acting element of DcRB7 gene directs GUS expression not only as root-specific but also as drought inducible.
