植物生长素的作用机制

介绍了生长素受体、生长素诱导基因以及生长素诱导ATPase活化,特别对近几年来生长素信号转导的研究进展进行了概述.     

植物的生长素结合蛋白

就植物中分离出的多种生长素结合蛋白,及其在植物体内的分布、分子结构和在生长素信号转导中的有关作用的研究进展作了介绍.     

植物铁结合蛋白基因研究现状

世界范围内约 30 %的人口缺铁 ,以妇女、儿童最严重。Ｌｉ等 (1 993) [14 ] 对北京纺织女工的一项调查表明 ,根据ＷＴＯ(1 975 )的标准有 34% 1 9岁 - 4 5岁的人缺镁。最近研究表明 ,铁的缺乏会阻碍大脑认识能力的发育。铁结合蛋白是一种广泛存在于动物、植物和微生物中的铁储藏蛋白。对植物种子、胚、正生长发育的植株和动物的储存铁研究表明 ,在所有情况下用于发育的储存铁的共同来源是铁结合蛋白。铁结合蛋白能富集数十亿倍于自由可溶性铁的铁原子。Ｂｅａｒｄ ,ｅｔａｌ [2 ](1 996 )用铁结合蛋白和大豆等食物治疗鼠的铁缺乏症 ,结果认…     

植物生长素受体

扼要介绍了生长素结合蛋白ABP1和泛素-蛋白酶体SCFTIR1作为生长素受体研究的新进展,并以这2种受体为基础初步分析了植物生长素受体体系的内容和范围。     

褪黑素受体

褪黑素是松果体分泌的主要激素,其功能活动通过特异的Ｇ蛋白耦联受体介导,本文综述褪黑素受体 分布、药理学特性,受体的克隆及受体基因结构特点。     

生长素受体研究的新进展

围绕Hertel和Venis对ABP1讨论的三个焦点,综述了生长素受体研究11年来的进展,探讨了当前生长素受体研究中的难点和热点。     

植物源抗菌肽的研究进展

植物抗菌肽是植物自身合成的能够防御环境中微生物侵害的一类小分子多肽.它们大都是阳离子多肽,有较好的热稳定性.根据作用位点和抗菌机理的不同,植物抗菌肽可分为三大类:第一类通过干扰微生物细胞壁的合成来抑制微生物生长;第二类作用于质膜使其产生穿膜孔洞,从而导致微生物因细胞物质外泄受损;第三类则通过抑制某些细胞器的作用而起到抑菌的效果.本文从抗菌肽的作用机理及其分类等方面对植物源抗菌肽的研究进展进行了综述.     

生长素结合蛋白研究进展

生长素(auxin)是植物体内普遍存在的一类植物激素,它对植物的生长发育起着多方面的调节作用,如促进细胞伸长,诱导细胞分化,促进生根和单性果实(parthenocarpic fruit)的发育等,同时生长素还抑制芽的发生及果实的衰老。生长素作用机理的研究表明,生长素可以诱导一些特殊基因的快速表达,促进RNA和蛋白质的合成。因此,生长素可能是通过调节基因的表达来发挥作用。“酸生长理论”(acid growth theory)则认为,在细胞膜上存在着生长素的受体,生长素与之结合后激活了细胞质膜上的质子泵,破除了细胞壁纤维结构间的交织点,细胞壁的可塑性增加,从而使细胞伸长。尽管对“酸生长理论”一直存在争议,但植物体内存在生长素受体的证据在不断积累。70年代末,关于生长素受体的研究工作虽已全     

生长素结构与其活性关系的揭示

生长素结构与活性之间关系是长期以来悬而未决的一个难题。最近的研究证明,生长素分子像“胶水”一样将受体TIR1与效应蛋白Aux／IAA“粘合”后,形成SCF^TIR1-生长素-Aux／IAA复合物,进而激活泛素连接酶3（SCF^TIR1）,起着促使Aux／IAA泛素化后的降解,转录因子ARFs得到活化后,启动一系列生长素响应基因的转录,于是植物表现出相应的生长发育状态。     

抗除草剂转基因植物的研究现状

主要对目前在农业上广泛采用的除草剂以及抗除草剂转基因植物的研究现状进行了阐述．介绍了非选择性除草剂和选择性除草剂的分类及其作用机理。并对杂草产生除草剂抗药性的机理进行了分析,此外还介绍了抗除草剂基因的作用机理和对转基因植物所产生的生理作用,另外对抗除草剂转基因植物的生物安全性问题,如对基因飘移和生物多样性的影响进行了讨论,并对新型除草剂的发展方向提出思考。     

生长素受体与信号转导机制研究进展

对生长素受体ABP1和TIR1及调控泛素化蛋白降解的生长素信号转导途径研究进展进行综述。     

TIR1终于被确证为生长素受体

生长素受体-TIR1近期被确定,解决了生长素研究中长期令人困惑的一大难题。生长素首先和TIR1结合并且促进TIR1和Aux／IAA蛋白质的相互作用。TIR1和其他至少3种F-box蛋白质一起发挥作用,激活了泛素化的蛋白质降解过程,启动了基因转录,从而导致了植物生长发育过程中的生长素反应。     

Auxin Receptors and Auxin Binding Proteins

In the last few years, a large number of auxin-binding proteins (ABPs) have been reported. Implicitly or explicitly, interest in such proteins resides in their possible role as auxin receptors. Many of these proteins are characterized as ABPs solely by their susceptibility to covalent photolabeling by tritiated azido-indole-3-acetic acid. In most cases where the labeled polypeptides have been identified, they turn out to have roles unconnected with primary auxin perception. It seems likely that auxin is binding to sites of catholic specificity in these cases and the influence of experimental protocols on the data is discussed. Because the term ABP implies that auxin binding affects the function of that protein, the importance of establishing further criteria before photolabeled peptides can be termed ABPs is emphasized. Applying such criteria, only a very few ABPs are currently of interest and only one of these, maize ABP1, has been characterized in detail. This protein is located primarily within the lumen of the endoplasmic reticulum, although an important fraction appears to function on the outside of the plasma membrane. The protein has a wide species distribution and it now seems highly probable that it is a genuine auxin receptor, the only protein for which such a function has yet been established. This conclusion is based on three independent lines of electrophysiological evidence, together with confocal imaging of cytoplasmic pH changes.     

How Does Auxin Enhance Cell Elongation? Roles of Auxin‐Binding Proteins and Potassium Channels in Growth Control

Elongation growth and a several other phenomena in plant development are controlled by the plant hormone auxin. A number of recent discoveries shed light on one of the classical problems of plant physiology: the perception of the auxin signal. Two types of auxin receptors are currently known: the AFB/TIR family of F box proteins and ABP1. ABP1 appears to control membrane transport processes (H+ secretion, osmotic adjustment) while the TIR/AFBs have a role in auxin-induced gene expression. Models are proposed to explain how membrane transport (e.g., K+ and H+ fluxes) can act as a cross-linker for the control of more complex auxin responses such as the classical stimulation of cell elongation.     

Modeling Auxin Transport and Plant Development

The plant hormone auxin plays a critical role in plant development. Central to its function is its distribution in plant tissues, which is, in turn, largely shaped by intercellular polar transport processes. Auxin transport relies on diffusive uptake as well as carrier-mediated transport via influx and efflux carriers. Mathematical models have been used to both refine our theoretical understanding of these processes and to test new hypotheses regarding the localization of efflux carriers to understand auxin patterning at the tissue level. Here we review models for auxin transport and how they have been applied to patterning processes, including the elaboration of plant vasculature and primordium positioning. Second, we investigate the possible role of auxin influx carriers such as AUX1 in patterning auxin in the shoot meristem. We find that AUX1 and its relatives are likely to play a crucial role in maintaining high auxin levels in the meristem epidermis. We also show that auxin influx carriers may play an important role in stabilizing auxin distribution patterns generated by auxin-gradient type models for phyllotaxis.     

烟草薄层培养生长素结合蛋白ABP1的定位和ABP1在细胞分化中的变化

以烟草（Nicotiana tabacum L.)盛花期花梗薄层为材料,研究营养芽分化的不同时期生长素结合蛋白（ABP1)在组织与细胞中的分布变化,免疫荧光标记结果表明,烟草花梗中ABP1主要分布于表皮及亚表皮1－2层细胞内。不同分化期ABP1在烟草花梗薄层原生质体中的表达不同,细胞分化旺盛期ABP1的表达最强,分化后期ABP1的表达有所减弱;Western blotting结果表明,ABP1多克隆抗血清与烟草花梗薄层细胞及分化过程中26kD蛋白有免疫交叉反应。     

Auxin perception and signal transduction

The action of auxin on whole plants is very complex, but we are starting to understand how some of the earliest events are signalled in single cells. There is now good evidence that auxin induces rapid events at the plasma membrane by binding to a population of the auxin-binding protein ABPI, which is associated with a membrane-spanning docking protein, possibly a G-protein-coupled receptor (GPCR). ABPI is targeted to the endoplasmic reticulum (ER) lumen, but it does not appear to bind auxin within the ER and its function (if any) in this location is unknown. It is also not known how the protein reaches the cell surface, but it is possible that it is exported together with its docking protein. Binding of auxin causes a conformational change affecting the C-terminus of ABPI and it is likely that this change serves to activate the receptor at the plasma membrane. The signal transduction pathway appears to involve activation of phospholipase A₂(PLA₂) leading to the production of lipid second messengers which activate the plasma membrane proton ATPase (H⁻-ATPase) by a phosphorylation-dependent mechanism. Branch points exist that could potentially lead from this pathway to responses in the nucleus, but there is not yet any firm evidence that ABP1 is involved in such responses. Since intracellular auxin concentrations are correlated with sensitivity in some cases, it is possible that there is also a site of auxin perception inside the cell.