Pretreatment with H_2O_2 Alleviates Aluminum-induced Oxidative Stress in Wheat Seedlings

Hydrogen peroxide(H2O2) is a key reactive oxygen species(ROS) in signal transduction pathways leading to activation of plant defenses against biotic and abiotic stresses.In this study,we investigated the effects of H2O2 pretreatment on aluminum(Al) induced antioxidant responses in root tips of two wheat(Triticum aestivum L.) genotypes,Yangmai-5(Al-sensitive) and Jian-864(Al-tolerant).Al increased accumulation of H2O2 and O2r· leading to more predominant lipid peroxidation,programmed cell death and root elon...     

Allelic Analyses of the Arabidopsis YUC1 Locus Reveal Residues and Domains Essential for the Functions of YUC Family of Flavin Monooxygenases

Flavin monooxygenases(FMOs) play critical roles in plant growth and development by synthesizing auxin and other signaling molecules.However,the structure and function relationship within plant FMOs is not understood.Here we defined the important residues and domains of the Arabidopsis YUC1 FMO,a key enzyme in auxin biosynthesis.We previously showed that simultaneous inactivation of YUC1 and its homologue YUC4 caused severe defects in vascular and floral development.We mutagenized the yuc4 mutant and screene...     

Rice OsRAD21-2 is Expressed in Actively Dividing Tissues and its Ectopic Expression in Yeast Results in Aberrant Cell Division and Growth

Rad21 and its meiotic counterpart Rec8,the key components of the cohesin complex,are essential for sister chromatid cohesion and chromosome segregation in mitosis and meiosis,respectively.In contrast to yeast and vertebrates,which have only two RAD21/REC8 genes,the rice genome encodes four Rad21/Rec8 proteins.Here,we report on the cloning and characterization of OsRAD21-2 from rice(Oryza sativa L.).Phylogenetic analysis of the full-length amino acids showed that OsRad21-2 was grouped into the plant-specific...     

WBC27,an Adenosine Tri-phosphate-binding Cassette Protein,Controls Pollen Wall Formation and Patterning in Arabidopsis

In flowering plants,the exine components are derived from tapetum.Despite its importance to sexual plant reproduction,little is known about the translocation of exine materials from tapetum to developing microspores.Here we report functional characterization of the arabidopsis WBC27 gene.WBC27 encodes an adenosine tri-phosphate binding cassette(ABC) transporter and is expressed preferentially in tapetum.Mutation of WBC27 disrupted the exine formation.The wbc27 mutant microspores began to degenerate once rel...     

An oral health care guideline for institutionalised older people

Institutionalized older people are prone to oral health problems and their negative impact due to frailty, disabilities, multi-morbidity, and multiple medication use. Until recently, no evidence-based oral health care guideline for institutionalized older people has been available. For that reason, the Dutch Association of Nursing Home Physicians developed the Oral health care Guideline for Older people in Long-term care Institutions (OGOLI), meeting the requirements of the AGREE instrument for assessing a guideline's quality. This short report presents the keynotes and the content of the Oral health care Guideline. Most recommendations are based on expert opinions. Only 4 recommendations (education, pneumonia, use of an electric toothbrush, and fluoride rinsing in case of a sudden increase of oral plaque amount) are based on evidence level A2 conclusions. This emphasizes the need for further research on oral health of institutionalized older people.     

植物下胚轴向光弯曲机制研究进展

植物向光弯曲生长主要是由于其向光和背光面生长素的不对称分布引起。近年来研究发现,在不同强度的蓝光单侧照射下,植物可能存在不同的向光弯曲调节机制。目前,关于向光素PHOT1介导弱蓝光引起的下胚轴弯曲研究较为详细,即PHOT1感受蓝光后,与其下游的信号蛋白NPH3、RPT2和PKS1相互作用,调控生长素运输蛋白的活性及定位,诱导生长素的不对称分布引起向光弯曲。PHOT1和PHOT2以功能冗余方式调节强蓝光引起的植物下胚轴向光弯曲,NPH3可能作为共享调节因子,引发不同的信号转导通路实现功能互补。此外,其他光受体、激素、蛋白激酶、蛋白磷酸酶以及Ca2＋也参与了植物向光弯曲的调节。本文就近年来有关植物下胚轴向光弯曲信号组分及可能的网络关系进行总结,并对该研究领域存在的问题及今后可能的研究方向进行展望。     

高等植物中铁的代谢机制

铁在高等植物的生长发育中发挥着重要作用,但随着人类的耕作及土壤的盐碱化,缺铁已成为一个世界性植物营养问题。高等植物在长期的进化过程中,形成了完善的对环境铁信号响应的体系。本文围绕植物与环境的相互作用,综述了近年来植物铁营养的吸收、转运、分配和储存的研究进展,并总结了植物中铁营养代谢调控的相关机理。     

荔枝若干重要果实品质性状的QTL分析

以‘马贵荔＇ב焦核三月红＇76株F_1代群体为试材,检测了酒石酸、苹果酸、蔗糖含量和单果重4个果实性状分离的情况。结果表明,4个性状表现为连续分布,具有数量性状的典型特征,与4个果实性状连锁的QTL位点23个,其中控制酒石酸的QTL为2个,控制苹果酸的QTL为4个,控制蔗糖的QTL为12个和控制单果重的QTL为5个。各QTL的LOD值在3.15～5.61之间,可解释13.85%～88.3%的表型变异。     

‘津田’芜菁Transparent Testa Glabra 1（BrTTG1）基因的克隆及表达分析

TTG1（Transparent Testa Glabra 1）蛋白是一种WD40类蛋白,参与植物的生长和发育。采用RT-PCR方法从芜菁品种‘津田＇中克隆了BrTTG1 cDNA序列（GenBank登录号HM208590）。该基因cDNA开放阅读框长度为1 014 bp,编码一个由337个氨基酸残基组成的蛋白,该蛋白分子量为37.28 kDa,理论等电点为4.66。与其他植物中的TTG1蛋白进行同源性比对结果显示,BrTTG1与甘蓝型油菜的TTG1同源性最高。BrTTG1蛋白在31～337位氨基酸处含有WD40超家族的保守结构域。荧光定量PCR检测BrTTG1在‘津田＇芜菁不同组织中的表达结果表明,该基因在有花青素合成的红色‘津田＇芜菁根皮中表达量最高。     

丛枝菌根形成过程及其信号转导途径

丛枝菌根是由一类土壤中古老的丛枝菌根真菌与植物根系形成的互利互惠共生体。通过共生作用丛枝菌根真菌帮助宿主植物提高水和矿质营养（特别是磷）的吸收效率。作为回报,大约20%的光合作用产物被转移到丛枝菌根真菌中,供其完成自身的生活史。丛枝菌根形成的过程中,需要植物与丛枝菌根真菌之间进行一系列信号分子的识别、交换以及信号转导作用,这一过程由一系列植物和菌根真菌的基因控制。首先,植物会分泌一种植物激素——独角金内酯来诱导菌根真菌加速分支,而菌根真菌也会分泌脂质几丁寡糖促进植物与其形成菌根。加速分支的菌根真菌接触到植物根部以后,会附着在植物根的表皮并形成附着胞,通过附着胞穿透植物根的表皮,最后进入维管组织附近的皮层细胞并在其中不断进行二叉分支,形成特有的丛枝结构。通过对模式植物共生现象的研究,已经发现很多植物基因参与到共生形成的信号转导过程中,包括早期植物反应的基因、菌根与根瘤共生共同需要的转导因子以及菌根特异的信号分子等。本文对菌根的形成过程及信号转导途径进行详细的介绍,为人们深入研究菌根关系提供参考。