[Objective] Genetic Engineering technology was used to regulate the expression of PttGA20-oxidase gene thus restrained plant height growth and internode elongation for cultivating dwarfed plant.[Method] Based on the R...[Objective] Genetic Engineering technology was used to regulate the expression of PttGA20-oxidase gene thus restrained plant height growth and internode elongation for cultivating dwarfed plant.[Method] Based on the RNAi principle,the gene specific sequences of PttGA20-oxidase in the antisense and sense orientations interrupted by a gene sequence from GUS were cloned into a binary vector pBI121.The selection marker gene npt Ⅱ was replaced with bar gene to RNAi plasmid.[Result] After undergone different endonuclease restrictions,the constructed constraint vector released different segments whose sizes were similar to that of target segment,which demonstrated that the RNAi plasmid of PttGA20-oxidase gene was successfully constructed.[Conclusion] The experiment provided a new way for culturing dwarfed plant.展开更多
Gibberellin （GA） 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant d...Gibberellin （GA） 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant dwarf and GA-deficient phenotype,with a final stature that was less than half of its wild-type counterpart.The endogenous bioactive GAs are markedly decreased in the H032 mutant,and application of bioactive GAs （GA3 or GA4） can reverse the dwarf phenotype.The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR.An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant,which might be due to the enhancer role of the CaMV 35S promoter.RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene.BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases,which is a novel type of GA2ox that uses C20-GAs （GA12 and/or GA53） as the substrates.Interestingly,we found that a GA biosynthesis inhibitor,paclobutrazol,positively regulated the OsGA2ox6 gene.Unlike the over-expression of OsGA2ox1,which led to a high rate of seed abortion,the H032 mutant retained normal flowering and seed production.These results indicate that OsGA2ox6 mainly affects plant stature,and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding.展开更多
G2 pea exhibits an apical senescence delaying phenotype under short-day （SD） conditions; however, the structural basis for its apical development is still largely unknown. In the present study, the apical meristem o...G2 pea exhibits an apical senescence delaying phenotype under short-day （SD） conditions; however, the structural basis for its apical development is still largely unknown. In the present study, the apical meristem of SD-grown G2 pea plants underwent a transition from vegetative to indeterminate inflorescence meristem, but the apical meristem of long-day （LD）-grown G2 pea plants would be further converted to determinate floral meristem. Both SD signal and GA3 treatment enhanced expression of the putative calcium transporter PPF1, and pea homologs of TFL1 （LF and DET）, whereas LD signal suppressed their expression at 60 d post-flowering compared with those at 40 d post-flowering. Both PPF1 and LF expressed at the vegetative and reproductive phases in SD-grown apical buds, but floral initiation obviously increased the expression level of PPF1 compared with the unchanged expression level of LF from 40 to 60 d post-flowering. In addition, although the floral initiation significantly enhanced the expression levels of PPF1 and DET, DET was mainly expressed after floral initiation in SD-grown apil buds. Therefore, the main structural difference between LD- and SD-grown apical meristem in G2 pea lies in whether their apical indeterminate inflorescence meristem could be converted to the determinate structure.展开更多
The gibberellins(GAs)are phytohormones that play fundamental roles in almost every aspect of plant growth and development.Although GA biosynthetic and signaling pathways are well understood,the mechanisms that control...The gibberellins(GAs)are phytohormones that play fundamental roles in almost every aspect of plant growth and development.Although GA biosynthetic and signaling pathways are well understood,the mechanisms that control GA homeostasis remain largely unclear in plants.Here,we demonstrate that the homeobox transcription factor(TF)HB40 of the HD-Zip family regulates GA content at two additive con-trol levels in Arabidopsis thaliana.We show that HB40 expression is induced by GA and in turn reduces the levels of endogenous bioactive GAs by simultaneously reducing GA biosynthesis and increasing GA deac-tivation.Consistently,HB40 overexpression leads to typical GA-deficiency traits,such as small rosettes,reduced plant height,delayed flowering,and male sterility.By contrast,a loss-of-function hb40 mutation enhances GA-controlled growth.Genome-wide RNA sequencing combined with molecular-genetic ana-lyses revealed that HB40 directly activates the transcription of JUNGBRUNNEN1(JJUB1),a key TF that re-presses growth by suppressing GA biosynthesis and signaling.HB40 also activates genes encoding GA 2-oxidases(GA2oxs),which are major GA-catabolic enzymes.The effect of HB40 on plant growth is ultimately mediated through the induction of nuclear growth-repressing DELLA proteins.Collectively,our results reveal the important role of the HB40-JUB1 regulatory network in controlling GA homeostasis during plant growth.展开更多
文摘[Objective] Genetic Engineering technology was used to regulate the expression of PttGA20-oxidase gene thus restrained plant height growth and internode elongation for cultivating dwarfed plant.[Method] Based on the RNAi principle,the gene specific sequences of PttGA20-oxidase in the antisense and sense orientations interrupted by a gene sequence from GUS were cloned into a binary vector pBI121.The selection marker gene npt Ⅱ was replaced with bar gene to RNAi plasmid.[Result] After undergone different endonuclease restrictions,the constructed constraint vector released different segments whose sizes were similar to that of target segment,which demonstrated that the RNAi plasmid of PttGA20-oxidase gene was successfully constructed.[Conclusion] The experiment provided a new way for culturing dwarfed plant.
基金supported by grants from the Ministry of Sciences and Technology of China (No. 2005CB120805 and 2006AA10A101)the National Natural Science Foundation of China (No. 30621001 and 30871512)
文摘Gibberellin （GA） 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant dwarf and GA-deficient phenotype,with a final stature that was less than half of its wild-type counterpart.The endogenous bioactive GAs are markedly decreased in the H032 mutant,and application of bioactive GAs （GA3 or GA4） can reverse the dwarf phenotype.The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR.An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant,which might be due to the enhancer role of the CaMV 35S promoter.RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene.BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases,which is a novel type of GA2ox that uses C20-GAs （GA12 and/or GA53） as the substrates.Interestingly,we found that a GA biosynthesis inhibitor,paclobutrazol,positively regulated the OsGA2ox6 gene.Unlike the over-expression of OsGA2ox1,which led to a high rate of seed abortion,the H032 mutant retained normal flowering and seed production.These results indicate that OsGA2ox6 mainly affects plant stature,and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding.
基金Supported by the Southeast University Foundation for Excellent YoungScholars (4023001013)the Program for New Century Excellent Talentsin University.
文摘G2 pea exhibits an apical senescence delaying phenotype under short-day （SD） conditions; however, the structural basis for its apical development is still largely unknown. In the present study, the apical meristem of SD-grown G2 pea plants underwent a transition from vegetative to indeterminate inflorescence meristem, but the apical meristem of long-day （LD）-grown G2 pea plants would be further converted to determinate floral meristem. Both SD signal and GA3 treatment enhanced expression of the putative calcium transporter PPF1, and pea homologs of TFL1 （LF and DET）, whereas LD signal suppressed their expression at 60 d post-flowering compared with those at 40 d post-flowering. Both PPF1 and LF expressed at the vegetative and reproductive phases in SD-grown apical buds, but floral initiation obviously increased the expression level of PPF1 compared with the unchanged expression level of LF from 40 to 60 d post-flowering. In addition, although the floral initiation significantly enhanced the expression levels of PPF1 and DET, DET was mainly expressed after floral initiation in SD-grown apil buds. Therefore, the main structural difference between LD- and SD-grown apical meristem in G2 pea lies in whether their apical indeterminate inflorescence meristem could be converted to the determinate structure.
基金supported by the European Rogional Dovelop-ment Fund Project Center for Experimental Plant Biology(no.CZ.02.1.01/0.00.0/16.0190000738)and the Czech Sc ence Foundation(no.18-10349S).
文摘The gibberellins(GAs)are phytohormones that play fundamental roles in almost every aspect of plant growth and development.Although GA biosynthetic and signaling pathways are well understood,the mechanisms that control GA homeostasis remain largely unclear in plants.Here,we demonstrate that the homeobox transcription factor(TF)HB40 of the HD-Zip family regulates GA content at two additive con-trol levels in Arabidopsis thaliana.We show that HB40 expression is induced by GA and in turn reduces the levels of endogenous bioactive GAs by simultaneously reducing GA biosynthesis and increasing GA deac-tivation.Consistently,HB40 overexpression leads to typical GA-deficiency traits,such as small rosettes,reduced plant height,delayed flowering,and male sterility.By contrast,a loss-of-function hb40 mutation enhances GA-controlled growth.Genome-wide RNA sequencing combined with molecular-genetic ana-lyses revealed that HB40 directly activates the transcription of JUNGBRUNNEN1(JJUB1),a key TF that re-presses growth by suppressing GA biosynthesis and signaling.HB40 also activates genes encoding GA 2-oxidases(GA2oxs),which are major GA-catabolic enzymes.The effect of HB40 on plant growth is ultimately mediated through the induction of nuclear growth-repressing DELLA proteins.Collectively,our results reveal the important role of the HB40-JUB1 regulatory network in controlling GA homeostasis during plant growth.
