在植物响应紫外线B(ultraviolet-B,UV-B)的过程中,UV-B光受体UVR8(UV Resistance Locus 8)对植物的光形态建成和生长代谢等过程具有重要调控作用。为探究罗布麻属植物UV-B光受体信息,该研究通过罗布麻(Apocynum venetum)和大麻状罗布麻(...在植物响应紫外线B(ultraviolet-B,UV-B)的过程中,UV-B光受体UVR8(UV Resistance Locus 8)对植物的光形态建成和生长代谢等过程具有重要调控作用。为探究罗布麻属植物UV-B光受体信息,该研究通过罗布麻(Apocynum venetum)和大麻状罗布麻(A.cannabinum)全基因组数据进行UV-B光受体UVR8的筛选与生物信息学分析,同时利用转录组数据分析UV-B胁迫处理下的UVR8基因表达模式。结果表明:(1)罗布麻有6个UVR8基因,大麻状罗布麻有5个UVR8基因,前者分布在1、7、9和11号染色体上,后者分布在1、8和9号染色体上。(2)UVR8蛋白为亲水性稳定蛋白,定位在细胞核,不存在跨膜结构和信号肽,二级结构主要由延伸链、无规则卷曲、α-螺旋和β-转角构成。AvUVR8b和AcUVR8a蛋白三级结构与拟南芥UVR8(AtUVR8)最为类似,并且与小粒咖啡(CaUVR8)和伊德斯种咖啡(CeUVR8)的亲缘关系最近。同时发现罗布麻AvUVR8b和大麻状罗布麻AcUVR8a基因和蛋白结构与AtUVR8基因及蛋白高度相似。(3)当以一定剂量UV-B(17.52 kJ·m~(-2)·d~(-1))处理两种罗布麻植株时,AvUVR8b和AcUVR8a的表达量上调。据此推测在响应UV-B时,AvUVR8b基因在罗布麻中起主要作用,AcUVR8a基因在大麻状罗布麻中起主要作用。(4)顺式作用元件分析结果表明,UVR8的表达受光照、温度、水分、氧气和激素等因素的调控。该研究将为进一步研究罗布麻属UVR8的基因功能奠定基础,同时为解析罗布麻属植物适应UV-B的分子机制提供线索。展开更多
紫外线抗性位点8(UV resistance locus 8,UVR8)编码光受体蛋白,负责UV-B感知和信号转导,被认为参与调控其他的生理反应。文章对UVR8过表达和基因沉默植株的果实进行分析,结果表明:与对照组相比,UVR8过表达转基因番茄果实有着更长的贮藏...紫外线抗性位点8(UV resistance locus 8,UVR8)编码光受体蛋白,负责UV-B感知和信号转导,被认为参与调控其他的生理反应。文章对UVR8过表达和基因沉默植株的果实进行分析,结果表明:与对照组相比,UVR8过表达转基因番茄果实有着更长的贮藏期,其果实硬度显著高于野生型;对UVR8转基因番茄果实的过氧化氢酶(CAT)和过氧化物酶(POD)活性进行测定,结果发现过表达番茄果实的CAT、POD的酶活与野生型相比均显著提高,分别是野生型的2.5、2.3倍,而基因沉默番茄果实的酶活与野生型相比显著下降;同时对脂质过氧化指标的丙二醛(MDA)进行分析,表明每g过表达番茄果实中MDA物质的量有所降低,仅为野生型的1/2,而且每g基因沉默番茄果实中MDA物质的量与野生型相比明显升高。由以上结果可推测,UVR8基因在延长番茄果实采后贮藏期中发挥了作用。展开更多
The phytohormone jasmonate(JA)coordinates stress and growth responses to increase plant survival in unfavorable environments.Although JA can enhance plant UV-B stress tolerance,the mechanisms underlying the interactio...The phytohormone jasmonate(JA)coordinates stress and growth responses to increase plant survival in unfavorable environments.Although JA can enhance plant UV-B stress tolerance,the mechanisms underlying the interaction of UV-B and JA in this response remain unknown.In this study,we demonstrate that the UV RESISTANCE LOCUS 8-TEOSINTE BRANCHED1,Cycloidea and PCF 4-LIPOXYGENASE2(UVR8-TCP4-LOX2)module regulates UV-B tolerance dependent on JA signaling pathway in Arabidopsis thaliana.We show that the nucleus-localized UVR8 physically interacts with TCP4 to increase the DNA-binding activity of TCP4 and upregulate the JA biosynthesis gene LOX2.Furthermore,UVR8 activates the expression of LOX2 in a TCP4-dependent manner.Our genetic analysis also provides evidence that TCP4 acts downstream of UVR8 and upstream of LOX2 to mediate plant responses to UV-B stress.Our results illustrate that the UV-B-dependent interaction of UVR8 and TCP4 serves as an important UVR8-TCP4-LOX2 module,which integrates UV-B radiation and JA signaling and represents a new UVR8 signaling mechanism in plants.展开更多
The plant UV-B photoreceptor UV RESISTANCE LOCUS 8(UVR8)exists as a homodimer in its inactive ground state.Upon UV-B exposure,UVR8monomerizes and interacts with a downstreamkey regulator,theCONSTITUTIVE PHOTOMORPHOGEN...The plant UV-B photoreceptor UV RESISTANCE LOCUS 8(UVR8)exists as a homodimer in its inactive ground state.Upon UV-B exposure,UVR8monomerizes and interacts with a downstreamkey regulator,theCONSTITUTIVE PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYA(COP1/SPA)E3 ubiquitin ligase complex,to initiate UV-B signaling.Two WD40 proteins,REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1(RUP1)and RUP2 directly interact with monomeric UVR8 and facilitate UVR8 ground state reversion,completing the UVR8 photocycle.Here,we reconstituted the RUP-mediated UVR8 redimerization process in vitro and reported the structure of the RUP2-UVR8^(W285A) complex(2.0A).RUP2 and UVR8^(W285A) formed a heterodimer via two distinct interfaces,designated Interface 1 and 2.The previously characterized Interface 1 is found between the RUP2 WD40 domain and the UVR8 C27 subregion.The newly identified Interface 2 is formed through interactions between the RUP2 WD40 domain and the UVR8 core domain.Disruption of Interface 2 impairedUV-B induced photomorphogenic development in Arabidopsis thaliana.Further biochemical analysis indicated that both interfaces are important for RUP2-UVR8 interactions and RUP2-mediated facilitation of UVR8 redimerization.Our findings suggest that the two-interface-interaction mode is adopted by both RUP2 and COP1 when they interact with UVR8,marking a step forward in understanding the molecular basis that underpins the interactions between UVR8 and its photocycle regulators.展开更多
文摘紫外线抗性位点8(UV resistance locus 8,UVR8)编码光受体蛋白,负责UV-B感知和信号转导,被认为参与调控其他的生理反应。文章对UVR8过表达和基因沉默植株的果实进行分析,结果表明:与对照组相比,UVR8过表达转基因番茄果实有着更长的贮藏期,其果实硬度显著高于野生型;对UVR8转基因番茄果实的过氧化氢酶(CAT)和过氧化物酶(POD)活性进行测定,结果发现过表达番茄果实的CAT、POD的酶活与野生型相比均显著提高,分别是野生型的2.5、2.3倍,而基因沉默番茄果实的酶活与野生型相比显著下降;同时对脂质过氧化指标的丙二醛(MDA)进行分析,表明每g过表达番茄果实中MDA物质的量有所降低,仅为野生型的1/2,而且每g基因沉默番茄果实中MDA物质的量与野生型相比明显升高。由以上结果可推测,UVR8基因在延长番茄果实采后贮藏期中发挥了作用。
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)the National Natural Science Foundation of China(No.32370405).
文摘The phytohormone jasmonate(JA)coordinates stress and growth responses to increase plant survival in unfavorable environments.Although JA can enhance plant UV-B stress tolerance,the mechanisms underlying the interaction of UV-B and JA in this response remain unknown.In this study,we demonstrate that the UV RESISTANCE LOCUS 8-TEOSINTE BRANCHED1,Cycloidea and PCF 4-LIPOXYGENASE2(UVR8-TCP4-LOX2)module regulates UV-B tolerance dependent on JA signaling pathway in Arabidopsis thaliana.We show that the nucleus-localized UVR8 physically interacts with TCP4 to increase the DNA-binding activity of TCP4 and upregulate the JA biosynthesis gene LOX2.Furthermore,UVR8 activates the expression of LOX2 in a TCP4-dependent manner.Our genetic analysis also provides evidence that TCP4 acts downstream of UVR8 and upstream of LOX2 to mediate plant responses to UV-B stress.Our results illustrate that the UV-B-dependent interaction of UVR8 and TCP4 serves as an important UVR8-TCP4-LOX2 module,which integrates UV-B radiation and JA signaling and represents a new UVR8 signaling mechanism in plants.
基金supported by funds from the National Key R&D Program of China(2018YFA0507700 and 2017YFA0506100)the National Natural Science Foundation of China(31722017,31870753,and 32122011)+1 种基金the Foundation of Hubei Hongshan Laboratory(2021hszd010)the China Postdoctoral Science Foundation(2020M682437 for Ling Ma).
文摘The plant UV-B photoreceptor UV RESISTANCE LOCUS 8(UVR8)exists as a homodimer in its inactive ground state.Upon UV-B exposure,UVR8monomerizes and interacts with a downstreamkey regulator,theCONSTITUTIVE PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYA(COP1/SPA)E3 ubiquitin ligase complex,to initiate UV-B signaling.Two WD40 proteins,REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1(RUP1)and RUP2 directly interact with monomeric UVR8 and facilitate UVR8 ground state reversion,completing the UVR8 photocycle.Here,we reconstituted the RUP-mediated UVR8 redimerization process in vitro and reported the structure of the RUP2-UVR8^(W285A) complex(2.0A).RUP2 and UVR8^(W285A) formed a heterodimer via two distinct interfaces,designated Interface 1 and 2.The previously characterized Interface 1 is found between the RUP2 WD40 domain and the UVR8 C27 subregion.The newly identified Interface 2 is formed through interactions between the RUP2 WD40 domain and the UVR8 core domain.Disruption of Interface 2 impairedUV-B induced photomorphogenic development in Arabidopsis thaliana.Further biochemical analysis indicated that both interfaces are important for RUP2-UVR8 interactions and RUP2-mediated facilitation of UVR8 redimerization.Our findings suggest that the two-interface-interaction mode is adopted by both RUP2 and COP1 when they interact with UVR8,marking a step forward in understanding the molecular basis that underpins the interactions between UVR8 and its photocycle regulators.
