Chromosome and plasmid-encoded N-acyl homoserine lactones produced by Agrobacterium vitis wildtype and mutants that differ in their interactions with grape and tobacco     

Yaxin Li  Matthew R. Gronquist  Guixia Hao  Michele R. Holden  Anatol Eberhard  Russell A. Scott  Michael A. Savka  Erno Szegedi  Sandor Sule  Thomas J. Burr   《Physiological and Molecular Plant Pathology》2005,67(6):101

Agrobacterium vitis causes crown gall disease on grapevines. It also induces a specific necrosis on grape roots and a hypersensitive response (HR) on tobacco that are regulated by a complex quorum-sensing regulatory system. Strain F2/5 produces at least six N-acyl-homoserine lactones (AHLs) that function as signal molecules in quorum-sensing. The AHLs differ in acyl side chain length (8–16 carbons) as determined by gas chromatography/mass spectrometry and electrospray ionization tandem mass spectrometry. Mutant derivatives of F2/5 differ in ability to cause necrosis and the HR and show variable AHL profiles as determined by a thin-layer chromatography/biosensor assay. All wildtype A. vitis strains revealed the presence of long-chain AHLs regardless of tumorigenicity or ability to cause the HR. Whereas genes encoding long-chain AHLs are predicted to reside on the F2/5 chromosome, the determinants for short-chain AHLs were shown to be located on conjugal plasmids.  相似文献   

Predicting effective doses for the joint action of two fungicide applications   总被引：1，自引：0，他引：1  

N. D. Paveley †  J. M. Thomas  T. B. Vaughan  N. D. Havis  D. R. Jones 《Plant pathology》2003,52(5):638-647

A function was derived to predict fungicide efficacy when more than one application of a single active ingredient is made to a crop, given parameters describing the dose–response curves of the component single-spray applications. In the function, a second application is considered to act on that proportion of the total pathogen population which was uncontrollable at the time of the first application (represented by the lower asymptote of the dose–response curve for the first treatment), plus any additional part of the population which survived the first application as a result of a finite dose being applied. Data to estimate the single-spray dose–response curve parameters and validate predictions of two-spray programme efficacy were obtained from separate subsets of treatments in four field experiments. A systemic fungicide spray was applied to wheat at a range of doses, at one or both of two times (t₁ and t₂), in all dose combinations. Observed values of the area under the disease progress curve (AUDPC) for septoria leaf blotch (Mycosphaerella graminicola) were used to construct response surfaces of dose at t₁ by dose at t₂ for each culm leaf layer. Parameters were estimated from single-spray and zero-dose treatment data only. The model predicted a high proportion (R² = 71–95%) of the variation in efficacy of the two-spray programmes. AUDPC isobols showed that the dose required at t₂ was inversely related to the dose at t₁, but the slope of the relationship varied with the relative timings of t₁ and t₂ in relation to culm leaf emergence. Isobols were curved, so the effective dose – the total dose required to achieve a given level of disease suppression – was lower when administered as two applications.  相似文献   

Functional analysis of the 3′ end of avrBs3/pthA genes from two Xanthomonas species     

H. Ishihara  G. Ponciano  J. E. Leach  S. Tsuyumu   《Physiological and Molecular Plant Pathology》2003,63(6):329-338

The phytopathogens Xanthomonas oryzae pathovar (pv.) oryzae and Xanthomonas axonopodis pv. citri each contain several avrBs3/pthA family genes. Structural features of these genes important for avirulence and/or virulence functions include a central region of multiple direct repeats and three nuclear localization signals (NLSs) and an acidic activation domain (AAD) at the 3′ end. To identify other regions critical to function in the 3′ ends of these genes, we constructed several chimeras using apl1 and apl2 from X. axonopodis pv. citri and avrXa10 and avrXa7 from X. oryzae pv. oryzae and evaluated their functions by inoculation to citrus and rice. The apl1 and avrXa7 genes are major virulence determinants in citrus and rice, respectively, while the contributions of apl2 and avrXa10 to virulence are negligible or not measurable. Constructs that contained a 417 bp HincII-SphI fragment from the 3′ end of apl1 in combination with the repeats from avrXa7, avrXa10, and apl1 caused a canker phenotype on citrus. Interchange of the HincII-SphI fragment between avrXa7 and avrXa10 abolishes avrXa7 avirulence function and reduces its virulence but it does not affect avrXa10 avirulence function in rice. avrXa7 caused a hypersensitive response (HR) in citrus and replacement of it's 3′ end with that of apl1 resulted in loss of canker and induction of HR. Thus, the HincII-SphI fragment of the avrBs3/pthA gene family is important for avirulence and virulence functions in two different plant species, Oryza sativa and Citrus natsudaidai HAYATA.  相似文献   

棉花调亏灌溉的生理基础研究   总被引：8，自引：2，他引：8  

史文娟  康绍忠  宋孝玉 《干旱地区农业研究》2004,22(3):91-95

以盆栽棉花为材料,通过苗期和现蕾期不同程度的亏水处理(低、中、高三个水平),对调亏灌溉节水效应及生理机制进行了研究。结果表明:适时适度的水分亏缺可使植株旺盛的营养生长得以有效控制,株型和根冠比都更为理想。调亏期间,蒸腾速率和气孔导度都明显下降,而光合速率下降不明显,复水后光合速率和气孔导度明显恢复且接近或高于对照;此外,水分亏缺不仅影响棉桃的数量,而且影响单果重。表明适度的亏水处理可使水分利用效率明显提高,而经济产量接近或高于对照,同时节水20%以上。  相似文献   

Analysis of blood biochemistry and arterial blood gas of systemic inflammatory response syndrome in the early time after trauma     

ZHOU Ze-qiang  YANG Feng  HAN Qing 《园艺学报》2004,20(9):1716-1718

AIM: To explore the variation of blood biochemistry and arterial blood gas of patients with systemic inflammatory response syndrome (SIRS) in the early time after trauma and improve the diagnosis and first aid. METHODS: Eighty-eight patients with trauma from August 2003 to February 2004 were divided into two groups by their AIS-ISS90 score. The data of temperature, pulse, respiratory rate, white blood cell counts, Hb, blood glucose and arterial blood gas (PaO₂, PaCO₂, HCO₃^-, AG) were collected and compared with each group by statistic methods. RESULTS: Of the 88 patients, 49 underwent SIRS, 12 in light trauma group (ISS≥16) and 37 in severe trauma group (ISS<16). Compared with light trauma group, the data of pulse, respiratory rate, white blood cell counts, blood glucose, AG and rate of SIRS of severe trauma group were higher, PaO₂ and HCO₃^- were lower and the cases of PaCO₂>45 mmHg or <35 mmHg were more (P<0.01). The data of temperature and Hb had not significant difference between two groups (P>0.05). 13 patients had MODS in severe trauma group and 2 died while none had MODS or died in light trauma group. CONCLUSION: Application of AIS-ISS90 and SIRS-related blood biochemistry and arterial blood gas is beneficial for the diagnosis and treatment of patients in the early time after trauma.  相似文献   

Bt玉米对中红侧沟茧蜂发育的间接影响及室内行为研究     

贠桂玲  邓曙东  张青文  徐环李  蔡青年 《植物保护》2004,30(5):23-26

利用Y-型嗅觉仪研究了中红侧沟茧蜂(Microplitis Mediator Haliday)对Bt玉米、常规玉米、粘虫幼虫和其虫粪及虫害苗挥发物的行为反应,同时研究了Bt玉米对中红侧沟茧蜂发育的影响。结果表明,两种玉米健康植株的挥发物对中红侧沟茧蜂均有引诱作用;中红侧沟茧蜂对两种玉米的健康植株及机械损伤株挥发物之间的选择性无显著差异;相对于Bt玉米,中红侧沟茧蜂更趋向于选择常规玉米的虫伤苗及玉米-粘虫幼虫-虫粪混合物的挥发物。与对照(寄生于取食常规玉米粘虫的中红侧沟茧蜂)相比,寄生于取食Bt玉米粘虫幼虫的中红侧沟茧蜂幼虫历期延长,出茧率、茧重、羽化率、蜂重均有显著降低,茧历期、蜂历期则差异不显著。  相似文献   

乙烯对匍匐翦股颖ISR抗病反应中AsA-GSH循环及胼胝质沉积的影响     

姜寒玉  王亚峰  徐明  甘培文  张金林  马晖玲 《草业学报》2018,27(9):120-131

以匍匐翦股颖品种“Penn-A4”为试验材料,侵染立枯丝核菌后,经丁二醇(BDO)诱导产生系统抗性(ISR),喷施不同浓度的乙烯合成抑制剂氯化钴(CoCl₂)和促进剂1-氨基环丙烷羧酸(ACC)后,检测抗坏血酸-谷胱甘肽(AsA-GSH)循环中抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量及相关酶活性的变化,并观察匍匐翦股颖ISR反应中胼胝质沉积的变化。结果表明,乙烯抑制剂处理下,匍匐翦股颖幼苗中AsA含量较低,抗坏血酸过氧化物酶(APX)活性下降,大量GSH被催化还原为氧化型谷胱甘肽(GSSG),GSSG大量积累,同时谷胱甘肽还原酶(GR)活性较低,GSSG经GR少量还原为GSH。乙烯促进剂处理下,AsA含量较高,APX活性升高,GSSG在高活性GR作用下催化还原为GSH,使得GSH大量积累。因此在匍匐翦股颖ISR抗病反应中,高浓度乙烯促进AsA和GSH的大量积累,它们不仅参与了活性氧的代谢平衡,同时也作为信号分子在ISR抗病反应中起着重要作用。匍匐翦股颖感染褐斑病后,胼胝质主要沉积在厚壁细胞、韧皮部、木质部和表皮组织,其中厚壁细胞胼胝质沉积最多,表皮组织沉积最少。此外,胼胝质沉积面积在不同乙烯信号分子处理间存在差异,但随着处理时间的延长差异不显著。一定浓度的乙烯对ISR反应中胼胝质的沉积具有一定的影响,随着处理时间的延长显著增加,在100 μmol·L^-1ACC处理5 d后,胼胝质沉积总面积仅为9.916 mm²,处理10 d后升至最高,为38.396 mm²,但在病害侵染后期,胼胝质数量减少,在100 μmol·L^-1ACC处理15 d后,胼胝质沉积总面积降至20.052 mm²,反映了乙烯信号分子对胼胝质沉积的影响是一种短期效应,短期内可提高匍匐翦股颖植株抗病性,具有信号分子的短时效特点。研究结果为探清匍匐翦股颖ISR抗病响应中ET信号分子如何调控抗病生理特性提供了理论基础。  相似文献   

Effects of zinc oxide nanoparticles on the egg quality,immune response,zinc retention,and blood parameters of laying hens in the late phase of production          下载免费PDF全文

M. Abedini  F. Shariatmadari  M. A. Karimi Torshizi  H. Ahmadi 《Journal of animal physiology and animal nutrition》2018,102(3):736-745

The objective of this study was to evaluate the effects of dietary supplementation with zinc oxide nanoparticles (ZnO‐NPs) on the performance, egg quality, Zn retention, immunity responses, superoxide dismutase activity (SOD), egg malondialdehyde (MDA) content, and serum parameters in laying hens in the late phase of production. A total of 288 laying hens at 64 weeks of age were randomly assigned to 4 treatments with 6 replicates, and 12 birds within each group. Experimental diets included a corn‐soybean meal‐based diet (without Zn supplementation) and a basal diet supplemented with 80 mg/kg of Zn‐oxide, ZnO‐NPs, and Zn‐methionine. The results indicated that egg production and egg mass were significantly higher in the Zn‐methionine and ZnO‐NPs groups (p < .05). Also, eggshell thickness and shell strength increased in the ZnO‐NPs group as compared with the other groups (p < .05). Moreover, Zn supplementation decreased egg loss (p < .05). There were significant differences among treatments in Zn deposition in tibiotarsus, liver, pancreas, eggs, and excreta (p < .01). Antibody titre, heterophil (%(, and phytohemagglutinin (PHA) were significantly higher in birds fed with Zn‐supplemented diets (p < .05). In treatments supplemented with ZnO‐NPs and Zn‐methionine, the SOD activity in the liver, pancreas, and plasma was greater as compared with the other treatments (p < .05). The MDA content in eggs was significantly reduced in groups supplemented with Zn (p < .01). Moreover, dietary Zn supplementation significantly affected serum total protein, albumin, glucose, alkaline phosphatase activity, carbonic anhydrase activity, and Zn level (p < .05). In conclusion, this study demonstrated that dietary supplementation with ZnO‐NPs can improve the performance of laying hens. Therefore, ZnO‐NPs can enhance zinc absorption in the intestine of aged layers and can be a more suitable source of zinc than regular Zn‐oxide in diets.  相似文献   

Effects of Rapeseed Green Manure on Soil Fertility and Bacterial Community in Dryland Wheat Field   总被引：2，自引：0，他引：2  

LI WenGuang  YANG XiaoXiao  HUANG ChunGuo  XUE NaiWen  XIA Qing  LIU XiaoLi  ZHANG XiaoQi  YANG Si  YANG ZhenPing  GAO ZhiQiang 《中国农业科学》2019,52(15):2664-2677

  相似文献   

Bioinformatics Analysis of Bone Morphogenetic Protein 4 (BMP4) of Sheep     

FAN Zhen-hua  ZHANG Qiu-yue  FAN Rui-wen  REN Yu-hong 《中国畜牧兽医》2015,42(6):1370-1376

The assay was aimed to explore the biological characteristics of bone morphogenetic protein 4 (BMP4) of sheep,NCBI,DNAMAN DNAStar,TMHMM Server v.2.0,PsortⅡ,SignalP various bioinformatical softwares were used to speculate the physical and chemical properties,hydrophobic property,phosphorylation site,conservative structure domain,protein secondary structure of BMP4 protein.Also,the three-dimensional structure was forecasted with the SWISS-MODEL Workspace software.The results indicated that the BMP4 of sheep had high homologies with the BMP4 of various species.The encoded protein was a hydrophilic protein which was unstable.There was no transmembrane regions and it was likely to be located in the nucleus.What was more,there was signal peptide and eighteen phosphorylation sites.Through the forecast of functional domains,the protein had two functional domains,including the transforming growth factor-beta (TGF-beta) superfamily and TGF-beta propeptide superfamily.The result was consistent with the function of BMP4 gene family,it also demonstrated that BMP4 was a growth factor and it had the function of signal transduction.The amino acid homology between the predicted 3D structure of protein and template 3bmp.1.A was 88.29%.The bioinformatics analysis of BMP4 gene could provide reference for the further study in practice.  相似文献