Secondary vascular development is a key biological characteristic of woody plants and the basis of wood formation.Our understanding of gene expression regulation and dynamic changes in microRNAs(miRNAs)during secondar...Secondary vascular development is a key biological characteristic of woody plants and the basis of wood formation.Our understanding of gene expression regulation and dynamic changes in microRNAs(miRNAs)during secondary vascular development is still limited.Here we present an integrated analysis of the miRNA and mRNA transcriptome of six phase-specific tissues-the shoot apex,procambium,primary vascular tissue,cambium,secondary phloem,and secondary xylem-in Populus tomentosa.Several novel regulatory modules,including the PtoTCP20-miR396d-PtoGRF15 module,were identified during secondary vascular development in Populus.A series of biochemical and molecular experiments confirmed that PtoTCP20 activated transcription of the miR396d precursor gene and that miR396d targeted PtoGRF15 to downregulate its expression.Plants overexpressing miR396d(35S:miR396d)showed enhanced secondary growth and increased xylem production.Conversely,during the transition from primary to secondary vascular development,plants with downregulated PtoTCP20expression(PtoTCP20-SRDX),downregulated miR396 expression(35S:STTM396),and PtoGRF15 overexpression(35S:PtoGRF15)showed delayed secondary growth.Novel regulatory modules were identified by integrated analysis of the miRNA and mRNA transcriptome,and the regulatory role of the PtoTCP20-miR396d-PtoGRF15 signaling cascade in secondary vascular development was validated in Populus,providing information to support improvements in forest cultivation and wood properties.展开更多
Nitrate is the main source of nitrogen for plants but often distributed heterogeneously in soil.Plants have evolved sophisticated strategies to achieve adequate nitrate by modulating the root system architecture. The ...Nitrate is the main source of nitrogen for plants but often distributed heterogeneously in soil.Plants have evolved sophisticated strategies to achieve adequate nitrate by modulating the root system architecture. The nitrate acquisition system is triggered by the short mobile peptides C-TERMINALLY ENCODED PEPTIDES(CEPs)that are synthesized on the nitrate-starved roots,but induce the expression of nitrate transporters on the other nitrate-rich roots through an unclear signal transduction pathway. Here,we demonstrate that the transcription factors HBI1 and TCP20 play important roles in plant growth and development in response to fluctuating nitrate supply. HBI1 physically interacts with TCP20, and this interaction was enhanced by the nitrate starvation. HBI1 and TCP20 directly bind to the promoters of CEPs and cooperatively induce their expression. Mutation in HBIs and/or TCP20 resulted in impaired systemic nitrate acquisition response. Our solid genetic and molecular evidence strongly indicate that the HBI1-TCP20 module positively regulates the CEPs-mediated systemic nitrate acquisition.展开更多
基金This work was supported by the National Natural Science Foundation of China(32071726 and 32271825).
文摘Secondary vascular development is a key biological characteristic of woody plants and the basis of wood formation.Our understanding of gene expression regulation and dynamic changes in microRNAs(miRNAs)during secondary vascular development is still limited.Here we present an integrated analysis of the miRNA and mRNA transcriptome of six phase-specific tissues-the shoot apex,procambium,primary vascular tissue,cambium,secondary phloem,and secondary xylem-in Populus tomentosa.Several novel regulatory modules,including the PtoTCP20-miR396d-PtoGRF15 module,were identified during secondary vascular development in Populus.A series of biochemical and molecular experiments confirmed that PtoTCP20 activated transcription of the miR396d precursor gene and that miR396d targeted PtoGRF15 to downregulate its expression.Plants overexpressing miR396d(35S:miR396d)showed enhanced secondary growth and increased xylem production.Conversely,during the transition from primary to secondary vascular development,plants with downregulated PtoTCP20expression(PtoTCP20-SRDX),downregulated miR396 expression(35S:STTM396),and PtoGRF15 overexpression(35S:PtoGRF15)showed delayed secondary growth.Novel regulatory modules were identified by integrated analysis of the miRNA and mRNA transcriptome,and the regulatory role of the PtoTCP20-miR396d-PtoGRF15 signaling cascade in secondary vascular development was validated in Populus,providing information to support improvements in forest cultivation and wood properties.
基金This work was funded by the National Natural Science Foundation of China(Grant Nos.31970306,31600199,and 31670284)by China Postdoctoral Science Foundation(Grant Nos.2017M612259,2018T110684,and 2020M672047)+2 种基金by Shandong Province Natural Science Foundation(Grant Nos.ZR2019ZD16,JQ201708,and ZR2018ZC0334)by the Shandong Province Postdoctoral Science Foundation(Grant No.11200078311023 to J.W.)by Shandong Province Agricultural Variety Improvement Project(Grant No.2019LZGC-015)。
文摘Nitrate is the main source of nitrogen for plants but often distributed heterogeneously in soil.Plants have evolved sophisticated strategies to achieve adequate nitrate by modulating the root system architecture. The nitrate acquisition system is triggered by the short mobile peptides C-TERMINALLY ENCODED PEPTIDES(CEPs)that are synthesized on the nitrate-starved roots,but induce the expression of nitrate transporters on the other nitrate-rich roots through an unclear signal transduction pathway. Here,we demonstrate that the transcription factors HBI1 and TCP20 play important roles in plant growth and development in response to fluctuating nitrate supply. HBI1 physically interacts with TCP20, and this interaction was enhanced by the nitrate starvation. HBI1 and TCP20 directly bind to the promoters of CEPs and cooperatively induce their expression. Mutation in HBIs and/or TCP20 resulted in impaired systemic nitrate acquisition response. Our solid genetic and molecular evidence strongly indicate that the HBI1-TCP20 module positively regulates the CEPs-mediated systemic nitrate acquisition.
