RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants,but its role in plant growth and development remains unknown. Using cDNA array,we found that transcription of RAV1 is d...RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants,but its role in plant growth and development remains unknown. Using cDNA array,we found that transcription of RAV1 is downregulated by epibrassinolide (epiBL) in Arabidopsis suspension cells. RNA gel blot analysis revealed that epiBL-regulated RAV1 transcription involves neither protein phosphorylation/dephosphorylation nor newly synthesized protein,and does not require the functional BRI1,suggesting that this regulation might be through a new BR signaling pathway.Overexpressing RAV1 in Arabidopsis results in a retardation of lateral root and rosette leaf development,and the underexpression causes an earlier flowering phenotype,implying that RAV1 may function as a negative regulatory component of growth and development.展开更多
RAV1(Related to ABI3/VP1)is a plant-specific B3 and AP2 domain-containing transcription factor that acts as a negative regulator of growth in many plant species.The expression of RAV1 is downregulated by brassinostero...RAV1(Related to ABI3/VP1)is a plant-specific B3 and AP2 domain-containing transcription factor that acts as a negative regulator of growth in many plant species.The expression of RAV1 is downregulated by brassinosteroids(BRs);large-scale transcriptome analyses have shown that the expression of RAV1 was previously targeted by BRI1-EMS-SUPPRESOR1(BES1)and BRASSINAZOLE-RESISTANT1(BZR1),which are critical transcription factors for the BR-signaling process.Using RAV1-overexpressing transgenic plants,we showed that RAV1 overexpression reduced the BR signaling capacity,resulting in the downregulation of BR biosynthetic genes and BES1 expression.Furthermore,we demonstrated that BES1,not BZR1,is directly bound to the RAV1 promoter and repressed RAV1 expression,and vice versa;RAV1 is also bound to the BES1 promoter and repressed BES1 expression.This mutual inhibition was specific to RAV1 and BES1 because RAV1 exhibited binding activity to the BZR1 promoter but did not repress BZR1 expression.We observed that constitutively activated BR signaling phenotypes in bes1-D were attenuated by the repression of endogenous BES1 expression in transgenic bes1-D plants overexpressing RAV1.RNA-sequencing analysis of RAV1-overexpressing transgenic plants and bes1-D mutant plants revealed differentially expressed genes by RAV1 and BES1 and genes that were oppositely co-regulated by RAV1 and BES1.RAV1 and BES1 regulated different transcriptomes but co-regulated a specific set of genes responsible for the balance between growth and defense.These results suggested that the mutual inhibitory transcriptional activities of RAV1 and BES1 provide fine regulatory mechanisms for plant growth and development.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.39889003,30070074,30221002)a National Distinguished Young Scholar Award to Jia Yang LI.
文摘RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants,but its role in plant growth and development remains unknown. Using cDNA array,we found that transcription of RAV1 is downregulated by epibrassinolide (epiBL) in Arabidopsis suspension cells. RNA gel blot analysis revealed that epiBL-regulated RAV1 transcription involves neither protein phosphorylation/dephosphorylation nor newly synthesized protein,and does not require the functional BRI1,suggesting that this regulation might be through a new BR signaling pathway.Overexpressing RAV1 in Arabidopsis results in a retardation of lateral root and rosette leaf development,and the underexpression causes an earlier flowering phenotype,implying that RAV1 may function as a negative regulatory component of growth and development.
基金supported by grants from the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT,and Future Planning(NRF-2017R1A2B4002656 and 2020R1F1A1067946 to K.H.N.and 2021R1A6A3A13045111 to D.Y.)。
文摘RAV1(Related to ABI3/VP1)is a plant-specific B3 and AP2 domain-containing transcription factor that acts as a negative regulator of growth in many plant species.The expression of RAV1 is downregulated by brassinosteroids(BRs);large-scale transcriptome analyses have shown that the expression of RAV1 was previously targeted by BRI1-EMS-SUPPRESOR1(BES1)and BRASSINAZOLE-RESISTANT1(BZR1),which are critical transcription factors for the BR-signaling process.Using RAV1-overexpressing transgenic plants,we showed that RAV1 overexpression reduced the BR signaling capacity,resulting in the downregulation of BR biosynthetic genes and BES1 expression.Furthermore,we demonstrated that BES1,not BZR1,is directly bound to the RAV1 promoter and repressed RAV1 expression,and vice versa;RAV1 is also bound to the BES1 promoter and repressed BES1 expression.This mutual inhibition was specific to RAV1 and BES1 because RAV1 exhibited binding activity to the BZR1 promoter but did not repress BZR1 expression.We observed that constitutively activated BR signaling phenotypes in bes1-D were attenuated by the repression of endogenous BES1 expression in transgenic bes1-D plants overexpressing RAV1.RNA-sequencing analysis of RAV1-overexpressing transgenic plants and bes1-D mutant plants revealed differentially expressed genes by RAV1 and BES1 and genes that were oppositely co-regulated by RAV1 and BES1.RAV1 and BES1 regulated different transcriptomes but co-regulated a specific set of genes responsible for the balance between growth and defense.These results suggested that the mutual inhibitory transcriptional activities of RAV1 and BES1 provide fine regulatory mechanisms for plant growth and development.
