植物MYB转录因子与非生物胁迫响应研究

MYB转录因子家族是植物中最大的转录因子家族之一,在植物体内的多种生理生化反应中起着关键性作用,其中一项重要功能就是对非生物逆境的应答。这类转录因子通过调控生长发育,影响代谢产物的合成和影响激素信号等多方面参与非生物逆境的应答。介绍了MYB转录因子的结构特点和分类上的新发现,并综述了近几年MYB转录因子家族在植物响应干旱、高温、低温和高盐等非生物胁迫方面的研究进展。     

植物缺铁应答bHLH转录因子研究进展

铁是植物生命活动必需的微量元素之一,土壤中有效铁含量较低,易导致植物缺铁。bHLH转录因子家族多个成员参与植物缺铁响应,发挥重要的调控作用。为深入了解植物对缺铁的反应机制,文中对植物缺铁胁迫应答的bHLH转录因子的结构、分类和功能及其调控机制、介导的缺铁胁迫信号通路进行综述,为应用bHLH转录因子培育缺铁耐受作物或富铁作物提供理论依据和设计策略。     

植物WRKY转录因子在应对盐胁迫中的作用研究进展

土壤中的高含盐量严重限制了植物的生长和作物的产量。植物的许多转录因子在植物逆境胁迫中发挥着重要的作用,但仍有很多转录因子的分子机制目前尚不清楚。WRKY转录因子作为高等植物中最大的转录因子家族之一,参与并影响着植物生长发育的多个方面,在盐胁迫的多种不同响应途径中发挥重要作用。WRKY蛋白对基因表达的调控主要是通过与DNA特定顺式调控元件——W-box元件（TTGACC）的结合来实现的。近年来,从模式植物拟南芥（Arabidopsis）到农作物,已经有许多研究揭示了WRKY家族成员的作用和机制。本文综述了WRKY转录因子在应对盐胁迫方面的最新研究进展,探讨了WRKY转录因子研究目前存在的问题和未来的展望。     

植物中逆境反应相关的WRKY转录因子研究进展

WRKY转录因子是植物体内一类比较大的转录因子家族,它在植物的生长发育以及抗逆境反应中起着非常重要的作用。本文综述了WRKY转录因子在植物应对冻害、干旱、盐害等非生物胁迫与病原菌、虫害等生物胁迫反应中的重要调控功能,并概括了WRKY转录因子在调控这些逆境反应中的机制。     

AtHsfA2 modulates expression of stress responsive genes and enhances tolerance to heat and oxidative stress in Arabidopsis

In nature, plants are subject to changes of tempera-ture. Thus, like other organisms, plants have evolved strategies for preventing damage caused by rapid changes in temperature and for repairing what damage is unavoidable. Heat stress responses have been well documented in a wide range of organisms. In all spe-cies studied, the heat shock (HS) response is charac-terized by a rapid production and a transient accumu-lation of specific families of proteins known as heat shock proteins (Hsps) th…     

高等植物热激转录因子生物学特性及其在非生物胁迫适应中的作用

热激转录因子(HSFs)参与了植物生长发育的调控以及多种非生物胁迫适应基因的表达调控。HSFs通常形成同源三聚体,激活转录活性从而发挥功能。本文综述了热激转录因子的基本结构、亚细胞定位、转录调控、功能多样性及其在植物适应极端温度、盐害、干旱、强光和氧化胁迫等非生物胁迫过程中的作用。HSFs是提高高等植物抗多重胁迫的优质候选基因,对其深入研究具有重要的应用价值。未来,通过生物基因工程等手段利用HSFs提高各类作物抗性具有广阔的发展前景。     

ClpB/Hsp100 proteins and heat stress tolerance in plants

High-temperature stress can disrupt cellular proteostasis, resulting in the accumulation of insoluble protein aggregates. For survival under stressful conditions, it is important for cells to maintain a pool of native soluble proteins by preventing and/or dissociating these aggregates. Chaperones such as GroEL/GroES (Hsp60/Hsp10) and DnaK/DnaJ/GrpE (Hsp70/Hsp40/nucleotide exchange factor) help cells minimize protein aggregation. Protein disaggregation is accomplished by chaperones belonging to the Caseinolytic Protease (Clp) family of proteins. ClpB/Hsp100 proteins are strikingly ubiquitous and are found in bacteria, yeast and multi-cellular plants. The expression of these proteins is regulated by heat stress (HS) and developmental cues. Bacteria and yeast contain one and two forms of ClpB proteins, respectively. Plants possess multiple forms of these proteins that are localized to different cellular compartments (i.e. cytoplasm/nucleus, chloroplast or mitochondria). Overwhelming evidence suggests that ClpB/Hsp100 proteins play decisive roles in cell adaptation to HS. Mutant bacteria and yeast cells lacking active ClpB/Hsp100 proteins are critically sensitive to high-temperature stress. Likewise, Arabidopsis, maize and rice mutants lacking cytoplasmic ClpB proteins are very sensitive to heat. In this study, we present the structural and functional attributes of plant ClpB forms.     

Isolation of transcription factors binding auxin response elements using a yeast one-hybrid system

Plant hormones play an important role during higher plant embryogenesis. Auxin is central to the development of vascular tissues, formation of lateral and adventitious roots, control of apical dominance, and tropic responses. Auxin response element (AuxRE), present in the promoters of many auxin-induced genes, can confer auxin responsiveness. Using carrot somatic embryo under specific developmental phase, a cDNA expression library was constructed. Several plasmids were recombined containing the tetramer of AuxRE as a bait. After screening by a yeast one-hy-brid system, one positive clone was confirmed and characterized. Electrophoretic mobility shift assay showed that AxRF1 protein expressed in yeast cell could bind AuxRE in vitro. It suggests that AxRF1 participates in regulation of the expression of auxin responsive gene during carrot somatic embryogenesis.     

中国辣椒热胁迫转录因子的全基因组鉴定及热胁迫响应的初步分析

采用生物信息学方法,从中国辣椒(Capsicum chinense Jacq.)全基因组序列中鉴定得到28个热胁迫转录因子(HSF)候选基因,并对这些候选基因的染色体分布、基因结构及编码蛋白的3D结构特征进行了分析。结果显示:28个候选基因的编码蛋白长度为128~526 aa;系统发育分析结果表明,HSF可分为A、B、C 3个亚家族。进一步对热胁迫处理后的中国辣椒种质进行转录组分析,共检测到27个HSF转录本,与对照组相比,实验组中有25个基因对热胁迫有不同程度的响应。     

Isolation of transcription factors binding auxin response elements using a yeast one-hybrid system

Plant hormones play an important role during higher plant embryogenesis. Auxin is central to the development of vascular tissues, formation of lateral and adventitious roots, control of apical dominance, and tropic responses. Auxin response element (AuxRE), present in the promoters of many auxin-induced genes, can confer auxin responsiveness. Using carrot somatic embryo under specific developmental phase, a cDNA expression library was constructed. Several plasmids were recombined containing the tetramer of AuxRE as a bait. After screening by a yeast one-hybrid system, one positive clone was confirmed and characterized. Electrophoretic mobility shift assay showed that AxRF1 protein expressed in yeast cell could bind AuxRE in vitro. It suggests that AxRF1 participates in regulation of the expression of auxin responsive gene during carrot somatic embryogenesis.