Increased tolerance of rice to cold, drought and oxidative stresses mediated by the overexpression of a gene that encodes the zinc finger protein ZFP245

ZFP245 is a cold- and drought-responsive gene that encodes a zinc finger protein in rice. The ZFP245 protein localizes in the nucleus and exhibits trans-activation activity. Transgenic rice plants overexpressing ZFP245 were generated and found to display high tolerance to cold and drought stresses. The transgenic plants did not exhibit growth retardation, but showed growth sensitivity against exogenous abscisic acid, increased free proline levels and elevated expression of rice pyrroline-5-carboxylatesynthetase and proline transporter genes under stress conditions. Overproduction of ZFP245 enhanced the activities of reactive oxygen species-scavenging enzymes under stress conditions and increased the tolerance of rice seedlings to oxidative stress. Our data suggest that ZFP245 may contribute to the tolerance of rice plants to cold and drought stresses by regulating proline levels and reactive oxygen species-scavenging activities, and therefore may be useful for developing transgenic crops with enhanced tolerance to abiotic stress.     

cAMP 参与烟草悬浮细胞的ABA信号转导

ABA诱导型启动子(rd29A)重组到报告基因(GUS)的上游构建表达载体.通过农杆菌介导转化烟草,获得转基因植株.将转基因植株诱导愈伤组织,建立稳定、均一的转rd29A-GUS融合基因的悬浮培养细胞系.用ABA处理悬浮细胞24 h后GUS活性显著升高,说明外源ABA能够诱导rd29A启动子的表达,获得了用于ABA信号转导研究的实用细胞系.在ABA激活表达的细胞介质中加入尼克酰胺(cADPR合成酶的抑制剂)或U73122(PLC抑制剂)只能部分抑制ABA的效应,但如果加入蛋白激酶抑制剂K252a,抑制效果达95%以上.用可跨膜的cAMP的类似物8-Br-cAMP处理细胞发现,它能代替ABA的作用;当介质中加入1 mmol/L IBMX(磷酸二酯酶的抑制剂)增加cAMP的稳定性,发现低浓度的8-Br-cAMP与ABA相同的效应.以上结果表明cAMP参与了烟草悬浮细胞中ABA信号的传递.     

Changes of DHN1 expression and subcellular distribution in A. delicisoa cells under osmotic stress

The changes of DHN1 expression and subcellular distribution in A. delicisoa cells under osmotic stress were studied by using GFP as a reporter molecule. Through creating the Xba I and BamH I restriction sites at the ends of dhn1 by PCR, the expression vector for the fusion protein DHN1-mGFP4 was constructed by cloning dhn1 into plasmid pBIN-35SmGFP4. Then the DHN1-mGFP4 expression vector was transformed into A. delicisoa suspension cells by micropro-jectile bombardment method. Bright green fluorescence of GFP which shows the high-level expression of DHN1-mGFP4 was visualized after culture for 10 h. However, the green fluorescence was only located within the nucleus. By increasing the culture medium osmotic potential, the green fluorescence was visualized in the cytoplasm (mainly around the plasma membranes). The generation of GFP fluorescence in the cytoplasm was also promoted by increasing the medium osmotic potential. Moreover, GFP green fluorescence was abolished by protein synthesis inhibitor dicyclo     

脱落酸、多效唑和油菜素内酯对低温期间香蕉过氧化物酶和电导率的影响

在人工气候箱中模拟寒潮对香蕉幼苗造成的低温冷害 ,研究脱落酸、多效唑和油菜素内酯对低温胁迫期和低温胁迫恢复期香蕉幼苗叶片过氧化物酶和相对电导率的影响。试验表明 ,叶面喷施适量脱落酸、多效唑和油菜素内酯能够提高低温胁迫期和恢复期香蕉叶片的过氧化物酶活性并且降低叶片相对电导率。其最适浓度脱落酸为 2 0～ 2 5mg/ L;多效唑为 15～ 30 m g/ L;油菜素内酯为 0 .9～ 1.5m g/ L。     

ABA促进针叶树体细胞胚胎分化

文章介绍ABA促进针叶树体细胞胚胎分化调控机制和应用的研究进展     

植物对干旱胁迫的分子反应

干旱胁迫是影响植物生长发育的主要因子,渗透保护剂的合成和积累,脱水伤害的修复,自由基清除酶和LEA蛋白基因表达的增量调节能增加植物的耐干旱性。植物在干旱条件下至少有4条信号转导途径,其中2条信号途径是依赖ABA的,另外2条途径是不依赖ABA的,在植物干旱胁迫的信号转导中,双组分的组氨酸激酶可能起渗透感受器的作用,Ca^2 和IP3可能是脱水信号的第2信使,转基因植物是一种评价编码蛋白功能的良好系统。     

The role of protein kinases in the regulation of plant growth and development

We review the role of protein kinases in plant hormone-mediatedsignalling, nutrient signalling and cell cycle control and in the crosstalkbetween these different contributors to plant growth regulation. The areas ofhormone-mediated signalling covered include ABA-mediated responses to osmoticstress, wounding and pathogen attack, as well as ethylene and cytokininsignalling pathways. These areas involve members of several major protein kinasefamilies, including the SNFl-related protein kinase-2 (SnRK2) subfamily, thecalcium-dependent protein kinase (CDPK) family, the mitogen activated protein(MAP) kinase family, the glycogen synthase kinase (GSK)- 3/shaggy family and thereceptor-like protein kinase (RPK) family. In the section on nutrient signallingwe review the role of SnRK1 protein kinases in the global regulation of carbonmetabolism, including aspects of sugar sensing and assimilate partitioning, andwhat is known about nitrogen and sulphur nutrient signalling. In the cell cyclesection, we summarise progress in the elucidation of cell cycle control systemsin plants and discuss the interaction between cell cycle control anddevelopment. We expand further on the hypothesis of crosstalk between differentsignalling pathways in a separate section in which we discuss evidence forinteraction between plant growth regulators and the cell cycle, betweendifferent nutrient signalling pathways, between nutrient and cell cyclesignalling and between nutrient and ABA signalling.     

保卫细胞的ABA信号转导

植物激素脱落酸(ABA)调节植物体多种生理过程,尤其在一些逆境条件下,植物体中ABA大量合成,诱导气孔关闭,从而有效地调控植物体内的水分平衡.尽管人们对ABA诱导气孔关闭作用已得到共识,但有关信号转导的细节还很不清楚.该文简要介绍了研究气孔保卫细胞信号转导途径的相关技术以及与ABA信号转导直接相关的ABA受体、第二信使、蛋白质磷酸化和离子通道调节等方面的最新妍究进展.并在前人研究工作的基础上,勾画出气孔保卫细胞ABA、H2O2的信号转导模式图.     

Cell biological mechanism for triggering of ABA accumulation under water stress inVicia faba leaves

Water stress-induced ABA accumulation is a cellular signaling process from water stress perception to activation of genes encoding key enzymes of ABA biosynthesis, of which the water stress-signal perception by cells or triggering mechanism of the ABA accumulation is the center in the whole process of ABA related-stress signaling in plants. The cell biological mechanism for triggering of ABA accumulation under water stress was studied in leaves ofVicia faba. Mannitol at 890 mmol ·kg^-1 osmotic concentration induced an increase of more than 5 times in ABA concentration in detached leaf tissues, but the same concentration of mannitol only induced an increase of less than 40 % in ABA concentration in protoplasts. Like in detached leaf tissues, ABA concentration in isolated cells increased more than 10 times under the treatment of mannitol at 890 mmol · kg^-1 concentration, suggesting that the interaction between plasmalemma and cell wall was essential to triggering of the water stress-induced ABA accumulation. Neither Ca²⁺-chelating agent EGTA nor Ca²⁺channel activator A23187 nor the two cytoskeleton inhibitors, colchicine and cytochalasin B, had any effect on water stress-induced ABA accumulation. Interestingly water stress-induced ABA accumulation was effectively inhibited by a non-plasmalemma-permeable sulfhydryl-modifier PCMBS (p-chloromercuriphenyl-sulfonic acid), suggesting that plasmalemma protein(s) may be involved in the triggering of water stress-induced ABA accumulation, and the protein may contain sulfhydryl group at its function domain.     

树木气孔浸润级与SO_2伤害及ABA的防护作用

以常见绿化树种为材料 ,通过实地测定和熏烟实验 ,探讨了气孔浸润级与树木SO2 伤害的关系及ABA的防护效应 .结果表明 ,在特定环境下 ,相同树种的气孔浸润级较为稳定 ,不同树种的气孔浸润级差异较大 ;浸润级与叶绿素结合度呈负相关变化 ,但不明显 ;与K 渗出量呈正相关 (r =0 .92 ,α <0 .0 1) ,并按 95 %的置信度绘制了伤害预测图 .不同SO2 浓度条件下 ,对同一树种的气孔浸润级的影响甚小 ,不超过一个等级 ,K 渗出量则依大气SO2 浓度和树木吸S量的增加而增多 .气孔浸润级依ABA溶液处理浓度增大而降低 ,K 渗出量也相应减少 ,经 2 .5mol·L-1× 4h剂量的SO2 熏烟 ,预涂 30mol·L-1ABA者 ,降低了 1.5～ 3个浸润级 ,K 渗出量减少 36 .5 %～ 5 4.8% ,其测定值与自然对照值相近 ,防护作用显著 .