In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum thatemerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular aux...In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum thatemerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular auxinresponse machinery. However, mechanisms underlying this auxin response maximum-mediated root stem cell mainte-nance are not fully understood. Here, we present unexpected evidence that WUSCHEL-RELATED HOMEOBOX 5 （WOX5）transcription factor modulates expression of auxin biosynthetic genes in the quiescent center （QC） of the root and thusprovides a robust mechanism for the maintenance of auxin response maximum in the root tip. This WOX5 action is bal-anced through the activity of indole-3-acetic acid 17 （IAA17） auxin response repressor. Our combined genetic, cell biol-ogy, and computational modeling studies revealed a previously uncharacterized feedback loop linking WOX5-mediatedauxin production to IAA17-dependent repression of auxin responses. This WOX5-1AA17 feedback circuit further assuresthe maintenance of auxin response maximum in the root tip and thereby contributes to the maintenance of distal stemcell （DSC） populations. Our experimental studies and in silico computer simulations both demonstrate that the WOX5-iAA17 feedback circuit is essential for the maintenance of auxin gradient in the root tip and the auxin-mediated root DSCdifferentiation.展开更多
Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem an...Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem and typically exhibits low levels of cell division,is critical for root growth and development.Here,we show that the Arabidopsis thaliana SA overaccumulation mutant constitutively activated cell death 1(cad1),which exhibits increased cell division in the QC,is rescued by additional mutations in genes encoding the SA biosynthetic enzyme SALICYLIC ACID INDUCTION DEFFICIENT2(SID2)or the SA receptor NONEXPRESSER OF PR GENES1(NPR1),indicating that QC cell division in the cad1 mutant is promoted by the NPR1-dependent SA signaling pathway.The application of exogenous SA also promoted QC cell division in wild-type plants in a dose-dependent manner and largely suppressed the expression of genes involved in QC maintenance,including those encoding the APETALA2(AP2)transcription factors PLETHORA1(PLT1)and PLT2,as well as the homeodomain transcription factor WUSCHEL-RELATED HOMEOBOX5(WOX5).Moreover,we showed that SA promotes reactive oxygen species(ROS)production,which is necessary for the QC cell division phenotype in the cad1 mutant.These results provide insight into the function of SA in QC maintenance.展开更多
Plant somatic cells have the capability to switch their cell fates from differentiated to undifferen-tiated status under proper culture conditions,which is designated as totipotency.As a result,plant cells can easily ...Plant somatic cells have the capability to switch their cell fates from differentiated to undifferen-tiated status under proper culture conditions,which is designated as totipotency.As a result,plant cells can easily regenerate new tissues or organs from a wide variety of explants.However,the mechanism by which plant cells have such remarkable regeneration ability is still largely unknown.In this study,we used a set of meristem-specific marker genes to analyze the patterns of stem cell differentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro.Our studies furnish preliminary and important information on the patterns of the de novo stem cell differentiation during various types of in vitro organogenesis.展开更多
The root system of Arabidopsis thaliana comprises primary,lateral,and adventitious roots.Different types of roots are formed by diverse inductive cues and developmental programs.Here,we adopted the CRE/LOX system to t...The root system of Arabidopsis thaliana comprises primary,lateral,and adventitious roots.Different types of roots are formed by diverse inductive cues and developmental programs.Here,we adopted the CRE/LOX system to trace cell lineage during the three types of root formation under the control of the promoter of WUSCHEL-RELATED HOMEOBOX5.The results show that the cells forming adventitious roots during de novo root regeneration from detached leaves and lateral roots from the primary root are descendants of the WOX5-expressing root primordium.During the post-embryonic growth of the primary root,some vascular and root cap cells are descendants of the WOX5-expressing stem cell niche in the root apical meristem.Overall,our data suggest that the CRE/LOX system is a useful tool to trace cell lineage in different types of root organogenesis.展开更多
文摘In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum thatemerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular auxinresponse machinery. However, mechanisms underlying this auxin response maximum-mediated root stem cell mainte-nance are not fully understood. Here, we present unexpected evidence that WUSCHEL-RELATED HOMEOBOX 5 （WOX5）transcription factor modulates expression of auxin biosynthetic genes in the quiescent center （QC） of the root and thusprovides a robust mechanism for the maintenance of auxin response maximum in the root tip. This WOX5 action is bal-anced through the activity of indole-3-acetic acid 17 （IAA17） auxin response repressor. Our combined genetic, cell biol-ogy, and computational modeling studies revealed a previously uncharacterized feedback loop linking WOX5-mediatedauxin production to IAA17-dependent repression of auxin responses. This WOX5-1AA17 feedback circuit further assuresthe maintenance of auxin response maximum in the root tip and thereby contributes to the maintenance of distal stemcell （DSC） populations. Our experimental studies and in silico computer simulations both demonstrate that the WOX5-iAA17 feedback circuit is essential for the maintenance of auxin gradient in the root tip and the auxin-mediated root DSCdifferentiation.
基金supported by the National Natural Science Foundation of China Grant(31670187 and 31972388 to C.Y.)。
文摘Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem and typically exhibits low levels of cell division,is critical for root growth and development.Here,we show that the Arabidopsis thaliana SA overaccumulation mutant constitutively activated cell death 1(cad1),which exhibits increased cell division in the QC,is rescued by additional mutations in genes encoding the SA biosynthetic enzyme SALICYLIC ACID INDUCTION DEFFICIENT2(SID2)or the SA receptor NONEXPRESSER OF PR GENES1(NPR1),indicating that QC cell division in the cad1 mutant is promoted by the NPR1-dependent SA signaling pathway.The application of exogenous SA also promoted QC cell division in wild-type plants in a dose-dependent manner and largely suppressed the expression of genes involved in QC maintenance,including those encoding the APETALA2(AP2)transcription factors PLETHORA1(PLT1)and PLT2,as well as the homeodomain transcription factor WUSCHEL-RELATED HOMEOBOX5(WOX5).Moreover,we showed that SA promotes reactive oxygen species(ROS)production,which is necessary for the QC cell division phenotype in the cad1 mutant.These results provide insight into the function of SA in QC maintenance.
基金supported by grants from the Ministry of Science and Technology of China(No.2007CB948200)the National Natural Science Foundation(NNSF)of China(Grant Nos.90917015 and 30770217).
文摘Plant somatic cells have the capability to switch their cell fates from differentiated to undifferen-tiated status under proper culture conditions,which is designated as totipotency.As a result,plant cells can easily regenerate new tissues or organs from a wide variety of explants.However,the mechanism by which plant cells have such remarkable regeneration ability is still largely unknown.In this study,we used a set of meristem-specific marker genes to analyze the patterns of stem cell differentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro.Our studies furnish preliminary and important information on the patterns of the de novo stem cell differentiation during various types of in vitro organogenesis.
基金We thank S.Wen for technical assistance.This work was supported by grants from the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB27030103)the National Natural Science Foundation of China(31630007)+1 种基金the Key Research Program of CAS(QYZDB-SSWSMC010)National Key Laboratory of Plant Molecular Genetics.
文摘The root system of Arabidopsis thaliana comprises primary,lateral,and adventitious roots.Different types of roots are formed by diverse inductive cues and developmental programs.Here,we adopted the CRE/LOX system to trace cell lineage during the three types of root formation under the control of the promoter of WUSCHEL-RELATED HOMEOBOX5.The results show that the cells forming adventitious roots during de novo root regeneration from detached leaves and lateral roots from the primary root are descendants of the WOX5-expressing root primordium.During the post-embryonic growth of the primary root,some vascular and root cap cells are descendants of the WOX5-expressing stem cell niche in the root apical meristem.Overall,our data suggest that the CRE/LOX system is a useful tool to trace cell lineage in different types of root organogenesis.
