Glycogen synthase kinase 3(GSK3)proteins play key roles in brassinosteroid(BR)signaling during plant growth and development by phosphorylating various substrates.However,how GSK3 protein stability and activity are the...Glycogen synthase kinase 3(GSK3)proteins play key roles in brassinosteroid(BR)signaling during plant growth and development by phosphorylating various substrates.However,how GSK3 protein stability and activity are themselves modulated is not well understood.Here,we demonstrate in vitro and in vivo that C-TERMINAL DOMAIN PHOSPHATASELIKE 3(Os CPL3),a member of the RNA Pol II CTD phosphatase-like family,physically interacts with Os GSK2 in rice(Oryza sativa).Os CPL3 expression was widely detected in various tissues and organs including roots,leaves and lamina joints,and was induced by exogenous BR treatment.Os CPL3 localized to the nucleus,where it dephosphorylated Os GSK2 at the Ser-222 and Thr-284 residues to modulate its protein turnover and kinase activity,in turn affecting the degradation of BRASSINAZOLERESISTANT 1(BZR1)and BR signaling.Loss of Os CPL3 function resulted in higher Os GSK2 abundance and lower Os BZR1 levels,leading to decreased BR responsiveness and alterations in plant morphology including semi-dwarfism,leaf erectness and grain size,which are of fundamental importance to crop productivity.These results reveal a previously unrecognized role for Os CPL3 and add another layer of complexity to the tightly controlled BR signaling pathway in plants.展开更多
Plant architecture is a critical agronomic trait directly affecting planting density and crop yield.Phosphate(Pi)starvation in rice(Oryza sativa)leads to a significant reduction in tiller number and a more upright lea...Plant architecture is a critical agronomic trait directly affecting planting density and crop yield.Phosphate(Pi)starvation in rice(Oryza sativa)leads to a significant reduction in tiller number and a more upright leaf angle.Insensitivity to brassinosteroid(BR)signaling can lead to similar phenotypes.However,the molecular mechanisms underlying how Piaffects plant architecture through brassinosteroid signaling remain obscure.In this study,we demonstrate that the Pi starvation-induced E3 ligase OsPUB77 regulates rice shoot architecture by affecting leaf angle and tiller number.We further revealed that the Pi-signalingrelated transcription factor RLl1a releases its repression of the expression of OsPUB77 under Pi deficiency.Subsequently,the accumulated OsPUB77 influences shoot architecture by ubiquitinating OsBZR3 to inhibit BR signaling.Furthermore,we found that natural variation in two single-nucleotide polymorphisms within the OsPUB77 U-box domain coding OsPUB77^(R530) results in higher ubiquitin transfer activity than OsPUB77^(1530) due to a strongerinteraction with E2.Introducing the OsPUB77pro::OsPUB77^(R530I) transgene into the ospub77-1 background confirmed that OsPUB77^(R530) results in more upright leaves.Collectively,our work identifies an RLI1a-OsPUB77-OsBZR3 module that mediates the crosstalk between Pi and BR signaling to shape shoot architecture in response to Pi starvation in rice.展开更多
基金supported by the National Natural Science Foundation of China under grant no.31971811。
文摘Glycogen synthase kinase 3(GSK3)proteins play key roles in brassinosteroid(BR)signaling during plant growth and development by phosphorylating various substrates.However,how GSK3 protein stability and activity are themselves modulated is not well understood.Here,we demonstrate in vitro and in vivo that C-TERMINAL DOMAIN PHOSPHATASELIKE 3(Os CPL3),a member of the RNA Pol II CTD phosphatase-like family,physically interacts with Os GSK2 in rice(Oryza sativa).Os CPL3 expression was widely detected in various tissues and organs including roots,leaves and lamina joints,and was induced by exogenous BR treatment.Os CPL3 localized to the nucleus,where it dephosphorylated Os GSK2 at the Ser-222 and Thr-284 residues to modulate its protein turnover and kinase activity,in turn affecting the degradation of BRASSINAZOLERESISTANT 1(BZR1)and BR signaling.Loss of Os CPL3 function resulted in higher Os GSK2 abundance and lower Os BZR1 levels,leading to decreased BR responsiveness and alterations in plant morphology including semi-dwarfism,leaf erectness and grain size,which are of fundamental importance to crop productivity.These results reveal a previously unrecognized role for Os CPL3 and add another layer of complexity to the tightly controlled BR signaling pathway in plants.
基金supported by the National Key Research and Development Program of China(2021YFF1000400)the National Natural Science Foundation of China(32472028)the Natural Science Foundation of Zhejiang Province,China(grant no.LZ25C150003).
文摘Plant architecture is a critical agronomic trait directly affecting planting density and crop yield.Phosphate(Pi)starvation in rice(Oryza sativa)leads to a significant reduction in tiller number and a more upright leaf angle.Insensitivity to brassinosteroid(BR)signaling can lead to similar phenotypes.However,the molecular mechanisms underlying how Piaffects plant architecture through brassinosteroid signaling remain obscure.In this study,we demonstrate that the Pi starvation-induced E3 ligase OsPUB77 regulates rice shoot architecture by affecting leaf angle and tiller number.We further revealed that the Pi-signalingrelated transcription factor RLl1a releases its repression of the expression of OsPUB77 under Pi deficiency.Subsequently,the accumulated OsPUB77 influences shoot architecture by ubiquitinating OsBZR3 to inhibit BR signaling.Furthermore,we found that natural variation in two single-nucleotide polymorphisms within the OsPUB77 U-box domain coding OsPUB77^(R530) results in higher ubiquitin transfer activity than OsPUB77^(1530) due to a strongerinteraction with E2.Introducing the OsPUB77pro::OsPUB77^(R530I) transgene into the ospub77-1 background confirmed that OsPUB77^(R530) results in more upright leaves.Collectively,our work identifies an RLI1a-OsPUB77-OsBZR3 module that mediates the crosstalk between Pi and BR signaling to shape shoot architecture in response to Pi starvation in rice.
