Gravitropism is an essential adaptive response of land plants.Asymmetric auxin gradients across plant organs,interpreted by multiple auxin signaling components including AUXIN RESPONSE FACTOR7(ARF7),trigger differenti...Gravitropism is an essential adaptive response of land plants.Asymmetric auxin gradients across plant organs,interpreted by multiple auxin signaling components including AUXIN RESPONSE FACTOR7(ARF7),trigger differential growth and bending response.However,how this fundamental process is strictly maintained in nature remains unclear.Here,we report that gravity stimulates the transcription of METHYL ESTERASE17(MES17)along the lower side of the hypocotyl via ARF7-dependent auxin signaling.The asymmetric distribution of MES17,a methyltransferase that converts auxin from its inactive form methyl indole-3-acetic acid ester(MeI AA)to its biologically active form free-IAA,enhanced the gradient of active auxin across the hypocotyl,which in turn reversely amplified the asymmetric auxin responses and differential growth that shape gravitropic bending.Taken together,our findings reveal the novel role of MES17-mediated auxin homeostasis in gravitropic responses and identify an ARF7-triggered feedback mechanism that reinforces the asymmetric distribution of active auxin and strictly controls gravitropism in plants.展开更多
基金supported by the National Natural Science Foundation of China(projects 31670275,32061143005,and 31870252)Shandong Natural Science Foundation ZR2021QC067the Specialized Fund for the Basic Research Operating Expenses Program of Shandong University(2017JQ04)。
文摘Gravitropism is an essential adaptive response of land plants.Asymmetric auxin gradients across plant organs,interpreted by multiple auxin signaling components including AUXIN RESPONSE FACTOR7(ARF7),trigger differential growth and bending response.However,how this fundamental process is strictly maintained in nature remains unclear.Here,we report that gravity stimulates the transcription of METHYL ESTERASE17(MES17)along the lower side of the hypocotyl via ARF7-dependent auxin signaling.The asymmetric distribution of MES17,a methyltransferase that converts auxin from its inactive form methyl indole-3-acetic acid ester(MeI AA)to its biologically active form free-IAA,enhanced the gradient of active auxin across the hypocotyl,which in turn reversely amplified the asymmetric auxin responses and differential growth that shape gravitropic bending.Taken together,our findings reveal the novel role of MES17-mediated auxin homeostasis in gravitropic responses and identify an ARF7-triggered feedback mechanism that reinforces the asymmetric distribution of active auxin and strictly controls gravitropism in plants.
