Light is a critical environmental cue that regulates a variety of diverse plant developmental processes.Cryptochrome 1(CRY1)is the major photoreceptor that mediates blue light-dependent photomorphogenic responses such as the inhibition of hypocotyl elongation.Gibberellin(GA)participates in the repression of photomorphogenesis and promotes hypocotyl elongation.However,the antagonistic interaction between blue light and GA is not well understood.Here,we report that blue light represses GA-induced degradation of the DELLA proteins(DELLAs),which are key negative regulators in the GA signaling pathway,via CRY1,thereby inhibiting the GA response during hypocotyl elongation.Both in vitro and in vivo biochemical analyses demonstrated that CRY1 physically interacts with GA receptors-GA-INSENSITIVE DWARF 1 proteins(GID1s)-and DELLAs in a blue light-dependent manner.Furthermore,we showed that CRY1 inhibits the association between GID1s and DELLAs.Genetically,CRY1 antagonizes the function of GID1s to repress the expression of cell elongation-related genes and thus hypocotyl elongation.Taken together,our findings demonstrate that CRY1 coordinates blue light and GA signali ng for plant photomorphogenesis by stabilizing DELLAs through the binding and in activation of GID1s,providing new in sights into the mechanism by which blue light antagonizes the function of GA in photomorphogenesis.
分析了F-box基因FOA1(F-box overexpressed/oppressed ABA signaling)在拟南芥不同组织器官的表达模式,以及ABA和NaCl对其表达的调节.结果发现,FOA1在根和花中表达较高茎中表达较低;外源ABA和NaCl处理能迅速诱导FOA1基因的表达.分析ABA处理条件下,过量表达株系FOA1ox1,FOA1ox2和T-DNA插入突变体foa1的表型发现,突变体foa1的种子萌发率下降、根较短、气孔开度较大、脯氨酸积累增加,且对外源ABA敏感;过量表达株系的表型则相反,对ABA的敏感性降低.ABA处理条件下,一系列ABA信号转导转录因子在foa1突变体中的转录水平比野生型高,而ABA及胁迫应答基因在foa1突变体中的转录水平则比野生型低.这些研究结果表明,FOA1是ABA信号通路相关基因,并可能起负调控作用.
In this study,we constructed dual-transgene vectors(pDT1,pDT7,and pDT7G) that simultaneously co-expressed two genes in plants.ACTIN2 and UBQ10 promoters were used to control the expression of these two genes.The 4×Myc.3×HA,and 3×Flag reporter genes allowed for the convenient identification of a tunable co-expression system in plants,whereas the dexamethasone(Dex) inducible reporter gene C-terminus of the glucocorticoid receptor(cGR) provided Dex-dependent translocation of the fusion gene between the nucleus and cytoplasm.The function of pDT vectors was validated using four pairwise genes in Nicotiana benthamiana or Anihidopsis thaliana.The co-expression efficiency of two genes from the pDT1 and pDT7 G vectors was 35%and 42%,respectively,which ensured the generation of sufficient transgenic materials.These pDT vectors are simple,reliable,efficient,and time-saving tools for the co-expression of two genes through a single transformation event and can be used in the study of protein-protein interactions or multi-component complexes.
Zhimin HeBin LiuXu WangMingdi BianReqing HeJindong YanMing ZhongXiaoying ZhaoXuanming Liu
F-box蛋白作为SCF(Skp1,Cullin and an F-box protein)复合体的成员,参与调节植物的生长发育过程。At5g22700为功能未知的F-box基因家族成员。本研究通过酵母双杂交分析At5g22700蛋白与ASK(Arabidopsis-SKP1-like)家族蛋白的相互作用,发现At5g22700蛋白的F-box结构域与ASK4蛋白相互作用。实时定量PCR分析该基因在不同组织器官中的表达,发现该基因在根和花中的表达量最高,说明At5g22700可能在根和花的发育中具有重要作用。以At5g22700基因的T-DNA插入突变体和过量表达转基因株系为材料,分析不同光照条件下幼苗的表型,发现蓝光下At5g22700过量表达转基因幼苗的主根比野生型长。这些研究结果表明,At5g22700在植物体内可能形成SCF复合体,并在植物幼苗主根伸长生长中起促进作用。
