Cotton leaf curl virus (CLCuV) belongs to the subgroup III of geminiviruses with single strand DNA genome. Study demonstrated that the bidirectional promoter of CLCuV had activity in Agrobacterium tumefaciens (Smith e...Cotton leaf curl virus (CLCuV) belongs to the subgroup III of geminiviruses with single strand DNA genome. Study demonstrated that the bidirectional promoter of CLCuV had activity in Agrobacterium tumefaciens (Smith et Townsend) Conn. This is the first report for the activity of the bidirectional promoter of geminivirus in A. tumefaciens. Results showed that the activity of the complementary sense promoter was stronger than that of virion sense promoter, and was detected 2-fold higher than that of CaMV 35S promoter in A. tumefaciens. Moreover, the promoter 5' deletion analysis indicated that the mean GUS activity driven by a 287 nucleotides complementary sense promoter fragment (from-287 to the translation initiation site) is 4 times higher than that driven by the whole complementary sense promoter in A. tumefaciens. This result suggested that there might exist negative regulatory elements in this deleted fragment. The function of other cis-elements included in CLCuV complementary sense promoter was also discussed in this paper.展开更多
Abscisic acid (ABA) plays an important role in plant growth and developmental processes. Although some ABA signal molecules, such as cADPR, Ca2+, etc., have been reported, there. was no evidence proving the involvemen...Abscisic acid (ABA) plays an important role in plant growth and developmental processes. Although some ABA signal molecules, such as cADPR, Ca2+, etc., have been reported, there. was no evidence proving the involvement of cAMP in A-B-A, signal transduction. In this present study, the constructed gene ( rd29A-GUS) was transformed into Nicotiana tabacum, and calli was induced from the transgenic plant. The suspension cells obtained from the callus grew well and uniformly. Treatment of the suspension cells with ABA led to an increase in GUS activity, indicating that these transgenic suspension cells are useful for the study of ABA signaling. Addition of nicotinamide (cADPR inhibitor) or U-73122 (phospholiphase C inhibitor) could only partially inhibit the increase of GUS activity elicited by ABA. The inhibitory effect of nicotinamide was enhanced by application of K252a (inhibitor of protein kinase). Treatment of the suspension cells with 8-Br-cAMP, a membrane-permeable analogue of cAMP, could partially replace the effect of ABA. Furthermore, intracellular addition of IBMX (phosphodiesterase inhibitor) mimicked die effect of exogenous cAMP on the deduction of expression of rd29A promoter. These results suggested that cAMP was an important messenger in ABA signal transduction in tobacco suspension cell.展开更多
The 5＇ fragment （1 647 bp） of the cotton glucuronosyltransferase gene （GhGlcAT1） was transcriptionally fused to the β-glucuronidase （GUS） gene, and functionally analyzed for important regulatory regions contro...The 5＇ fragment （1 647 bp） of the cotton glucuronosyltransferase gene （GhGlcAT1） was transcriptionally fused to the β-glucuronidase （GUS） gene, and functionally analyzed for important regulatory regions controlling gene expression in transgenic tobacco plants. GUS activity analysis revealed that the full-length promoter drives efficient expression of the GUS gene in the root cap, seed coat, pollen grains and trichomes. Exposure of the transgenic tobacco to various abiotic stresses showed that the promoter was mainly responsive to the sugars （glucose and sucrose） as well as gibberellic acid. Progressive upstream deletion analyses of the promoter showed that the region from -281 to ＋30 bp is sufficient to drive strong GUS expression in the trichomes of shoot, suggesting that the 311 bp region contains all cis-elements needed for trichome-specific expression. Furthermore, deletion analysis also revealed that the essential cis-element（s） for sucrose induction might be located between -635 and -281 bp. In addition, sequence analysis of the regulatory region indicated several conserved motifs among which some were shared with previously reported seed-specific elements and sugarresponsive elements, while others were related with trichome expression. These findings indicate that a 1 647-bp fragment of the cotton GhGIcAT1 promoter contains specific transcription regulatory elements, and provide clues about the roles of GhGIcAT 1 in cotton fiber development. Further analyses of these elements will help to elucidate the molecular mechanisms regulating the expression of the GhGlcAT1 gene during fiber elongation.展开更多
Limited availability of organic matter is a problem to sustain crop growth on sodic soil. Organic soil amendments are a costeffective source of nutrients to enhance crop growth. A field study was conducted to evaluate...Limited availability of organic matter is a problem to sustain crop growth on sodic soil. Organic soil amendments are a costeffective source of nutrients to enhance crop growth. A field study was conducted to evaluate the effect of an organic soil amendment bioaugmented with plant growth-promoting fungi(SF_(OA) ) in combination with gypsum on soil properties and growth and yield attributes of Withania somnifera, one of the most valuable crops of the traditional medicinal system in the world, on a sodic soil at the Aurawan Research Farm of CSIR-National Botanical Research Institute, Lucknow, India. The SF_(OA) used was prepared by pre-enriching farm waste vermicompost with plant growth-promoting fungi before mixing with pressmud and Azadirachta indica seed cake. The application of SF_(OA) at 10 Mg ha^(-1)after gypsum(25.0 Mg ha^(-1)) treatment significantly(P < 0.05) increased root length(by 96%) and biomass(by 125%) of Withania plants compared to the control without SF_(OA) and gypsum. Similarly, the highest withanolide contents were observed in leaves and roots of Withania plants under 10 Mg ha^(-1)SF_(OA) and gypsum. Combined application of SF_(OA) and gypsum also improved physical, chemical and enzymatic properties of the soil, with the soil bulk density decreasing by 25%, water-holding capacity increasing by 121%, total organic C increasing by 90%, p H decreasing by 17% and alkaline phosphatase, β-glucosidase, dehydrogenase and cellulase activities increasing by 54%, 128%, 81% and 96%, respectively, compared to those of the control. These showed that application of the SF_(OA) tested in this study might reclaim sodic soil and further support Withania cultivation and results were better when the SF_(OA) was applied after gypsum treatment.展开更多
文摘Cotton leaf curl virus (CLCuV) belongs to the subgroup III of geminiviruses with single strand DNA genome. Study demonstrated that the bidirectional promoter of CLCuV had activity in Agrobacterium tumefaciens (Smith et Townsend) Conn. This is the first report for the activity of the bidirectional promoter of geminivirus in A. tumefaciens. Results showed that the activity of the complementary sense promoter was stronger than that of virion sense promoter, and was detected 2-fold higher than that of CaMV 35S promoter in A. tumefaciens. Moreover, the promoter 5' deletion analysis indicated that the mean GUS activity driven by a 287 nucleotides complementary sense promoter fragment (from-287 to the translation initiation site) is 4 times higher than that driven by the whole complementary sense promoter in A. tumefaciens. This result suggested that there might exist negative regulatory elements in this deleted fragment. The function of other cis-elements included in CLCuV complementary sense promoter was also discussed in this paper.
文摘Abscisic acid (ABA) plays an important role in plant growth and developmental processes. Although some ABA signal molecules, such as cADPR, Ca2+, etc., have been reported, there. was no evidence proving the involvement of cAMP in A-B-A, signal transduction. In this present study, the constructed gene ( rd29A-GUS) was transformed into Nicotiana tabacum, and calli was induced from the transgenic plant. The suspension cells obtained from the callus grew well and uniformly. Treatment of the suspension cells with ABA led to an increase in GUS activity, indicating that these transgenic suspension cells are useful for the study of ABA signaling. Addition of nicotinamide (cADPR inhibitor) or U-73122 (phospholiphase C inhibitor) could only partially inhibit the increase of GUS activity elicited by ABA. The inhibitory effect of nicotinamide was enhanced by application of K252a (inhibitor of protein kinase). Treatment of the suspension cells with 8-Br-cAMP, a membrane-permeable analogue of cAMP, could partially replace the effect of ABA. Furthermore, intracellular addition of IBMX (phosphodiesterase inhibitor) mimicked die effect of exogenous cAMP on the deduction of expression of rd29A promoter. These results suggested that cAMP was an important messenger in ABA signal transduction in tobacco suspension cell.
文摘The 5＇ fragment （1 647 bp） of the cotton glucuronosyltransferase gene （GhGlcAT1） was transcriptionally fused to the β-glucuronidase （GUS） gene, and functionally analyzed for important regulatory regions controlling gene expression in transgenic tobacco plants. GUS activity analysis revealed that the full-length promoter drives efficient expression of the GUS gene in the root cap, seed coat, pollen grains and trichomes. Exposure of the transgenic tobacco to various abiotic stresses showed that the promoter was mainly responsive to the sugars （glucose and sucrose） as well as gibberellic acid. Progressive upstream deletion analyses of the promoter showed that the region from -281 to ＋30 bp is sufficient to drive strong GUS expression in the trichomes of shoot, suggesting that the 311 bp region contains all cis-elements needed for trichome-specific expression. Furthermore, deletion analysis also revealed that the essential cis-element（s） for sucrose induction might be located between -635 and -281 bp. In addition, sequence analysis of the regulatory region indicated several conserved motifs among which some were shared with previously reported seed-specific elements and sugarresponsive elements, while others were related with trichome expression. These findings indicate that a 1 647-bp fragment of the cotton GhGIcAT1 promoter contains specific transcription regulatory elements, and provide clues about the roles of GhGIcAT 1 in cotton fiber development. Further analyses of these elements will help to elucidate the molecular mechanisms regulating the expression of the GhGlcAT1 gene during fiber elongation.
文摘Limited availability of organic matter is a problem to sustain crop growth on sodic soil. Organic soil amendments are a costeffective source of nutrients to enhance crop growth. A field study was conducted to evaluate the effect of an organic soil amendment bioaugmented with plant growth-promoting fungi(SF_(OA) ) in combination with gypsum on soil properties and growth and yield attributes of Withania somnifera, one of the most valuable crops of the traditional medicinal system in the world, on a sodic soil at the Aurawan Research Farm of CSIR-National Botanical Research Institute, Lucknow, India. The SF_(OA) used was prepared by pre-enriching farm waste vermicompost with plant growth-promoting fungi before mixing with pressmud and Azadirachta indica seed cake. The application of SF_(OA) at 10 Mg ha^(-1)after gypsum(25.0 Mg ha^(-1)) treatment significantly(P < 0.05) increased root length(by 96%) and biomass(by 125%) of Withania plants compared to the control without SF_(OA) and gypsum. Similarly, the highest withanolide contents were observed in leaves and roots of Withania plants under 10 Mg ha^(-1)SF_(OA) and gypsum. Combined application of SF_(OA) and gypsum also improved physical, chemical and enzymatic properties of the soil, with the soil bulk density decreasing by 25%, water-holding capacity increasing by 121%, total organic C increasing by 90%, p H decreasing by 17% and alkaline phosphatase, β-glucosidase, dehydrogenase and cellulase activities increasing by 54%, 128%, 81% and 96%, respectively, compared to those of the control. These showed that application of the SF_(OA) tested in this study might reclaim sodic soil and further support Withania cultivation and results were better when the SF_(OA) was applied after gypsum treatment.
