Flg22诱导的海带（Saccharina japonica）孢子体防御反应的初步研究

以鞭毛蛋白N端一个保守的22个氨基酸多肽(flg22)为激发子,研究其诱导海带孢子体防御反应的特征,以丰富植物分子病理学理论.采用Evans blue染色方法发现,flg22诱导后2h内,未能观察到海带孢子体细胞死亡现象,诱导后4～10 h,观察到大量死亡的细胞.TUNEL(TdT-mediated dUTP-biotin nick and labeling)检测方法证实,受flg22诱导后海带孢子体有DNA断裂现象,而且3’-OH末端断裂的数量随诱导时间的延长而增多,并有从诱导部位向外扩散的趋势.运用Luminol荧光检测方法检测到受flg22诱导后海带孢子体H2O2释放量迅速增加,至3h时达到峰值,约为20 μmol/L.应用荧光染料2’,7’-二氢二氯荧光黄双乙酸钠(DCFH-DA)进行ROS组织学检测,发现flg22诱导后1h即观察到绿色的荧光信号,信号强度随诱导时间的延长而增加,诱导后3h信号最强,随后绿色荧光信号的强度逐渐减弱.ROS的产生趋势与Luminol荧光检测方法的结果相一致.结果表明,flg22也是诱导海带孢子体防御反应的有效激发子.     

基于防御酶活性分析准噶尔乌头拮抗内生菌对玉米斑点病菌的抑制作用

[目的]活体水平验证新疆准噶尔乌头(Aconitum soongaricum Stapf)拮抗内生细菌XJAS-ZB-14代谢物对两种玉米斑点病菌的抑制活性.[方法]做活体实验,制备玉米叶片酶粗提物,测定叶片总蛋白含量,对比分析来自不同处理组酶粗提液的超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APx)、过氧化氢酶(CAT)等抗病相关防卫酶系活性变化.用Graphpad Prism 5.0统计软件在α=0.01水平进行单因素方差分析.[结果]不同处理组玉米叶片总蛋白含量和各防御酶活性呈不同的变化趋势,XJASZB-14代谢物对玉米大斑病菌和玉米小斑病菌的防效率分别达32.48;和65.16;.[结论]该菌株发酵液有对玉米大、小斑点病菌有较强的抑杀作用.在玉米大、小斑点病菌的生物防治中具有较好的应用价值.     

大巴山系生物多样性保护现状及其发展对策

大巴山脉地处北半球亚热带的核心区域,该区生物区系起源古老、物种资源丰富、生态系统完整,保存有较多珍稀濒危、特有及古老生物类群,是中国17个生物多样性保护关键区域之一。为更好的保持本区域生态系统的稳定,本文对大巴山区生物多样性保护现状进行了分析讨论,旨在为更好的保护大巴山区生物多样性提出相应的保护对策。并在护林联防原有宗旨基础上,赋予"川陕鄂渝巴山地区护林联防委员会"更具时代意义的内涵,将"护林防火"提升为"生物多样性保护",将该组织更名为"大巴山生物多样性保护联盟"。     

Integrated effect of potassium humate and α-tocopherol applications on soil characteristics and performance of Phaseolus vulgaris plants grown on a saline soil

Soil salinity is one of the major problems of agriculture that limits plant performance, particularly in arid and semiarid regions. Therefore, the effect of potassium humate (KH) and α-tocopherol (TOC), used singly or in integration, on soil characteristics, and on plant performance, physio-biochemical attributes and antioxidative defense system of Phaseolus vulgaris L. plants grown under salt stress (EC = 6.35–6.42 dS m^?1) was investigated. Half g KH kg^?1 soil was used as soil amendment before sowing and 1.0 mM TOC was used as foliar spray twice; at 25 and 40 days after sowing. Results showed that, KH significantly improved soil physical and chemical properties, which positively reflected on plant growth and productivity, physio-biochemical attributes, mineral nutrients (N, P, K and Ca), osmoprotectants (soluble sugars and proline), non-enzymatic (ascorbic acid, glutathione and TOC) and enzymatic (superoxide dismutase, catalase and guaiacol peroxidase (GPOX)) antioxidants compared to untreated controls. The single TOC foliar application recorded the same positive results of KH. Integrated KH + TOC treatment was most effective compared to the single treatments. The above results recommended benefits of this integrated KH + TOC for the possibility of sustainable agronomic performance of common beans grown on saline soils.     

磷脂酶C参与ParA1诱导的烟草悬浮细胞死亡和防卫反应

【目的】研究寄生疫霉Phytophthora parasitica分泌的蛋白激发子ParA1诱导烟草悬浮细胞后,磷脂酶C(phospholipase C,PLC)参与ParA1诱导烟草过敏细胞死亡(hypersensitive cell death,HCD)和防卫反应。【方法】采用药理学方法,在烟草悬浮细胞中添加PLC抑制剂,比较烟草悬浮细胞受ParA1诱导后细胞死亡和多种防卫反应的差别。【结果】PLC特异性抑制剂U73122能完全抑制ParA1引起的烟草悬浮细胞死亡,氧迸发、胞外基质碱化和植保素scopoletin(7-羟基-6-甲氧基香豆素)积累都能显著地被抑制,5种防卫基因hin1、hsr203J、PR(pathogenesis-related)-1a、PR-1b和PAL等的转录表达也都受到U73122不同程度的抑制。【结论】ParA1处理烟草悬浮细胞后,PLC参与了ParA1诱导细胞死亡和防卫反应的信号传导过程。     

Determinants of fenhexamid effectiveness against grey mould on grapevine: Respective role of spray timing,fungicide resistance and plant defences

Botrytis bunch rot of grapes is mainly controlled by applying fungicides at three crop growth stages: the end of flowering (BBCH 68), bunch closure (BBCH 77) and the beginning of veraison (BBCH 81). The hydroxyanilide derivative fenhexamid is among the most effective fungicides registered to control Botrytis cinerea. Its effectiveness was examined in relation to spray timing, fungicide resistance and defense responses of grapevine. Overall, the earlier fenhexamid was applied, the more effective it was at controlling B. cinerea. Frequencies of B. cinerea strains which were resistant to fungicides were evaluated at harvest. The frequencies of resistant phenotypes were similar among treatments and years with the exception of a class of multidrug resistant strain (MDR 2) whose frequency appeared to increase after fenhexamid applications. If current spray programs including fenhexamid appear to control bunch rot at the current MDR frequency, a propagation of MDR 2 strains might lead to a decline in disease control. Finally, defense responses were studied in grapevine flowers/berries following fenhexamid application. None of the defense processes tested was induced in flowers/berries at stages 68 and 77. Only an increase in chitinase activity was observed in treated-berries at stage 81, suggesting that fenhexamid effectiveness was not related to a stimulation of defense responses.     

植物WRKY转录因子的结构特点及其在植物防卫反应中的作用

综述了WRKY转录因子的发现、结构特点、表达特点以及WRKY转录因子在各种植物防卫反应中的调控作用,指出WRKY转录因子是一类参与多种胁迫反应的诱导型转录因子,其N-端具有WRKYGQK高度保守的氨基酸序列,能够与基因启动子中的(T)(T)TGAC(C/T)序列(W盒)发生特异性结合,从而调节基因的表达,参与植物的各种生长和发育过程。     

苯甲酸和肉桂酸对番茄幼苗根部保护酶及膜质过氧化的影响

研究了苯甲酸和肉桂酸对番茄幼苗根部保护酶及膜质过氧化的影响.以珍珠岩作为基质,通过施加不同浓度的苯甲酸和肉桂酸研究在番茄苗期,不同浓度自毒物质主要成分对其根部超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、丙二醛(MDA)的影响.结果表明:两种物质的作用与其浓度和作用时间密切相关,不同浓度的苯甲酸和肉桂酸都促进了MDA含量的增加,其中以10 mmol/L的苯甲酸在第20天时促进作用最为明显;不同浓度的苯甲酸和肉桂酸在处理后的第5天使SOD的活性显著升高,但是从第10天开始苯甲酸促进作用减弱,5 mmol/L和10 mmol/L的苯甲酸转为抑制作用,而肉桂酸则在第20天转为抑制作用;两种自毒物质使POD的活性在处理后的第5和第10天显著高于对照水平,并且低浓度促进作用明显大于高浓度,但是在第20天急剧下降;不同浓度的苯甲酸和肉桂酸使CAT的活性在处理后的第10天达到最高,但是在第20天完全低于对照水平.可见,苯甲酸和肉桂酸的施用打破了番茄根部保护酶系统原有的平衡,造成了根系的膜质过氧化.     

番茄木虱取食对含Mi-1.2番茄抗氧化酶活性及防御反应相关基因表达的影响

Mi-1.2基因编码CC-NBS-LRR家族抗病蛋白,对线虫及刺吸式昆虫具有广谱抗性。以番茄木虱和携带Mi-1.2基因的番茄品系‘Motelle’作为研究体系,研究番茄木虱取食对番茄叶片抗氧化酶活性及防御反应相关基因表达的影响。结果表明：番茄木虱的取食显著提高了番茄叶片抗氧化酶POD、CAT、APX等的活性,同时诱导Mi-1.2基因表达;番茄木虱的取食上调SA合成有关基因PAL、SA信号途径标志基因PR-1（P4）及与Mi-1.2功能相关基因WRKY70、WRKY72a、WRKY72b的表达。JA/systemin信号途径和伤害有关的PinII、TPI-1、PR-6、PR-7、PR-5等及Prosystemin编码基因Psy的表达未发生变化;JA合成途径相关酶编码基因AOS2、LoxD下调表达,AOC的表达没有变化。SA信号途径可能参与Mi-1.2介导的番茄对于刺吸式昆虫番茄木虱的防御反应。另外,Mi-1.2的RNAi沉默不会改变上述基因的mRNA水平,说明Mi-1.2基因产物对这些基因的表达无调控作用。     

Jasmonic acid and abscisic acid play important roles in host–pathogen interaction between Fusarium graminearum and wheat during the early stages of fusarium head blight

The effect of phytohormones on the defense response of wheat against Fusarium graminearum infection was investigated. Infection of heads with F. graminearum induced accumulation of salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), and indole acetic acid (IAA). Exogenous phytohormone treatments showed crosstalk between them and a complex effect on expression of the genes ATB2, ExpB6, LEA Td16, PR1, Pdf1.2, PR4. JA treatment reduced F. graminearum growth and fusarium head blight (FHB) symptoms while an increase in FHB was observed with ABA. Transient down-regulation of allene oxide synthase (AOS) supports a complex role for JA in wheat head.