SAUR(SMALL AUXIN UP RNA)基因家族是促进下胚轴伸长的重要下游基因,然而在高温诱导的下胚轴伸长中SAURs受调控的分子机制尚有很多不明之处。热形态建成被定义为高等植物在最适温度和逆境高温之间的温和高温范围内发生的一系列形态变化...SAUR(SMALL AUXIN UP RNA)基因家族是促进下胚轴伸长的重要下游基因,然而在高温诱导的下胚轴伸长中SAURs受调控的分子机制尚有很多不明之处。热形态建成被定义为高等植物在最适温度和逆境高温之间的温和高温范围内发生的一系列形态变化。其中,高温诱导的下胚轴伸长是研究最为透彻的一个。该研究以拟南芥Col野生型、hy5突变体、35 S::HY5-HA/Col过表达植物和烟草为材料,采用抑制剂NPA处理实验、定量RT-PCR、染色质免疫共沉淀和双荧光素酶报告基因检测方法探索了高温调控SAUR1/2/3/4的分子机制。结果表明:(1)热形态建成信号转导通路中生长素处于HY5(ELONGATED HYPOCOTYL 5)的下游。(2)在20℃和29℃中,HY5抑制了SAUR1/2/3/4的转录。(3)在常温和高温中,HY5与SAUR1/2/3/4的启动子区染色质含有E-box的部分结合且这些结合被高温所抑制。(4)HY5对SAUR1/2/3/4的调控依然需要生长素的参与。综上认为,高温通过影响HY5与SAUR1/2/3/4启动子染色质的结合强度来调控这4个基因的转录,并且此调控过程需要生长素。该研究结果为高温调控下胚轴伸长下游基因的分子机制提供了新的见解。展开更多
Plant growth is controlled by integration of hormonal and light-signaling pathways. BZS1 is a B-box zinc finger protein previously characterized as a negative regulator in the brassinosteroid （BR）-signaling pathway ...Plant growth is controlled by integration of hormonal and light-signaling pathways. BZS1 is a B-box zinc finger protein previously characterized as a negative regulator in the brassinosteroid （BR）-signaling pathway and a positive regulator in the light-signaling pathway. However, the mechanisms by which BZS1/BBX20 integrates light and hormonal pathways are not fully understood. Here, using a quantitative proteomic workflow, we identified several BZSl-associated proteins, including light-signaling compo- nents COP1 and HY5. Direct interactions of BZS1 with COPI and HY5 were verified by yeast two-hybrid and co-immunoprecipitation assays. Overexpression of BZS1 causes a dwarf phenotype that is sup- pressed by the by5 mutation, while overexpression of BZSI fused with the SRDX transcription repressor domain （BZS1-SRDX） causes a long-hypocotyl phenotype similar to by5, indicating that BZSI＇s function requires HY5. BZSI positively regulates HY5 expression, whereas HY5 negatively regulates BZS1 protein level, forming a feedback loop that potentially contributes to signaling dynamics. In contrast to BR, strigolactone （SL） increases BZS1 level, whereas the SL responses of hypocoryl elongation, chlorophyll and HY5 accumulation are diminished in the BZSI-SRDX seedlings, indicating that BZS1 is involved in these SL responses. These results demonstrate that BZS1 interacts with HY5 and plays a central role in integrating light and multiple hormone signals for photomorphogenesis in Arabidopsis.展开更多
The basic leucine zipper(bZIP)transcription factor HY5 plays a multifaceted role in plant growth and development.Here the apple MdHY5 gene was cloned based on its homology with Arabidopsis HY5.Expression analysis demo...The basic leucine zipper(bZIP)transcription factor HY5 plays a multifaceted role in plant growth and development.Here the apple MdHY5 gene was cloned based on its homology with Arabidopsis HY5.Expression analysis demonstrated that MdHY5 transcription was induced by light and abscisic acid treatments.Electrophoretic mobility shift assays and transient expression assays subsequently showed that MdHY5 positively regulated both its own transcription and that of MdMYB10 by binding to E-box and G-box motifs,respectively.Furthermore,we obtained transgenic apple calli that overexpressed the MdHY5 gene,and apple calli coloration assays showed that MdHY5 promoted anthocyanin accumulation by regulating expression of the MdMYB10 gene and downstream anthocyanin biosynthesis genes.In addition,the transcript levels of a series of nitrate reductase genes and nitrate uptake genes in both wild-type and transgenic apple calli were detected.In association with increased nitrate reductase activities and nitrate contents,the results indicated that MdHY5 might be an important regulator in nutrient assimilation.Taken together,these results indicate that MdHY5 plays a vital role in anthocyanin accumulation and nitrate assimilation in apple.展开更多
Light plays a critical role in plant growth and development,but the mechanisms through which light regulates fruit ripening and nutritional quality in horticultural crops remain largely unknown.Here,we found that ELON...Light plays a critical role in plant growth and development,but the mechanisms through which light regulates fruit ripening and nutritional quality in horticultural crops remain largely unknown.Here,we found that ELONGATED HYPOCOTYL 5(HY5),a master regulator in the light signaling pathway,is required for normal fruit ripening in tomato(Solanum lycopersicum).Loss of function of tomato HY5(SlHY5)impairs pigment accumulation and ethylene biosynthesis.Transcriptome profiling identified 2948 differentially expressed genes,which included 1424 downregulated and 1524 upregulated genes,in the Slhy5 mutants.In addition,genes involved in carotenoid and anthocyanin biosynthesis and ethylene signaling were revealed as direct targets of SlHY5 by chromatin immunoprecipitation.Surprisingly,the expression of a large proportion of genes encoding ribosomal proteins was downregulated in the Slhy5 mutants,and this downregulation pattern was accompanied by a decrease in the abundance of ribosomal proteins.Further analysis demonstrated that SlHY5 affected the translation efficiency of numerous ripening-related genes.These data indicate that SlHY5 regulates fruit ripening both at the transcriptional level by targeting specific molecular pathways and at the translational level by affecting the protein translation machinery.Our findings unravel the regulatory mechanisms of SlHY5 in controlling fruit ripening and nutritional quality and uncover the multifaceted regulation of gene expression by transcription factors.展开更多
基金supported by a grant from National Institute of Health (NIH, R01GM066258)“One-hundred Talents Project” of Hebei province, China (E2013100004)supported by the China Scholarship Council
文摘Plant growth is controlled by integration of hormonal and light-signaling pathways. BZS1 is a B-box zinc finger protein previously characterized as a negative regulator in the brassinosteroid （BR）-signaling pathway and a positive regulator in the light-signaling pathway. However, the mechanisms by which BZS1/BBX20 integrates light and hormonal pathways are not fully understood. Here, using a quantitative proteomic workflow, we identified several BZSl-associated proteins, including light-signaling compo- nents COP1 and HY5. Direct interactions of BZS1 with COPI and HY5 were verified by yeast two-hybrid and co-immunoprecipitation assays. Overexpression of BZS1 causes a dwarf phenotype that is sup- pressed by the by5 mutation, while overexpression of BZSI fused with the SRDX transcription repressor domain （BZS1-SRDX） causes a long-hypocotyl phenotype similar to by5, indicating that BZSI＇s function requires HY5. BZSI positively regulates HY5 expression, whereas HY5 negatively regulates BZS1 protein level, forming a feedback loop that potentially contributes to signaling dynamics. In contrast to BR, strigolactone （SL） increases BZS1 level, whereas the SL responses of hypocoryl elongation, chlorophyll and HY5 accumulation are diminished in the BZSI-SRDX seedlings, indicating that BZS1 is involved in these SL responses. These results demonstrate that BZS1 interacts with HY5 and plays a central role in integrating light and multiple hormone signals for photomorphogenesis in Arabidopsis.
基金This work was supported by grants from the Natural Science Foundation of China(31325024 and 31601742)the Ministry of Education of China(IRT15R42)and Shandong Province Government(SDAIT-06-03).
文摘The basic leucine zipper(bZIP)transcription factor HY5 plays a multifaceted role in plant growth and development.Here the apple MdHY5 gene was cloned based on its homology with Arabidopsis HY5.Expression analysis demonstrated that MdHY5 transcription was induced by light and abscisic acid treatments.Electrophoretic mobility shift assays and transient expression assays subsequently showed that MdHY5 positively regulated both its own transcription and that of MdMYB10 by binding to E-box and G-box motifs,respectively.Furthermore,we obtained transgenic apple calli that overexpressed the MdHY5 gene,and apple calli coloration assays showed that MdHY5 promoted anthocyanin accumulation by regulating expression of the MdMYB10 gene and downstream anthocyanin biosynthesis genes.In addition,the transcript levels of a series of nitrate reductase genes and nitrate uptake genes in both wild-type and transgenic apple calli were detected.In association with increased nitrate reductase activities and nitrate contents,the results indicated that MdHY5 might be an important regulator in nutrient assimilation.Taken together,these results indicate that MdHY5 plays a vital role in anthocyanin accumulation and nitrate assimilation in apple.
基金the National Natural Science Foundation of China(grant Nos.31801601,31925035,and 31871855)the China Postdoctoral Science Foundation(2018T110153)the Youth Innovation Promotion Association CAS(2019083).
文摘Light plays a critical role in plant growth and development,but the mechanisms through which light regulates fruit ripening and nutritional quality in horticultural crops remain largely unknown.Here,we found that ELONGATED HYPOCOTYL 5(HY5),a master regulator in the light signaling pathway,is required for normal fruit ripening in tomato(Solanum lycopersicum).Loss of function of tomato HY5(SlHY5)impairs pigment accumulation and ethylene biosynthesis.Transcriptome profiling identified 2948 differentially expressed genes,which included 1424 downregulated and 1524 upregulated genes,in the Slhy5 mutants.In addition,genes involved in carotenoid and anthocyanin biosynthesis and ethylene signaling were revealed as direct targets of SlHY5 by chromatin immunoprecipitation.Surprisingly,the expression of a large proportion of genes encoding ribosomal proteins was downregulated in the Slhy5 mutants,and this downregulation pattern was accompanied by a decrease in the abundance of ribosomal proteins.Further analysis demonstrated that SlHY5 affected the translation efficiency of numerous ripening-related genes.These data indicate that SlHY5 regulates fruit ripening both at the transcriptional level by targeting specific molecular pathways and at the translational level by affecting the protein translation machinery.Our findings unravel the regulatory mechanisms of SlHY5 in controlling fruit ripening and nutritional quality and uncover the multifaceted regulation of gene expression by transcription factors.
