胞内钙库对小麦叶锈菌侵染之过敏反应的影响

使用影响胞内Ca²⁺库和钙通道的药物预注射小麦叶片,观察其对小麦受叶锈菌侵染诱发的过敏反应(HR)的影响。结果表明,对小麦叶片预注射不同浓度的胞内Ca²⁺螯合剂(BAPTA-AM)后接种叶锈菌小种260,随着注射药物浓度的增高,寄主细胞发生HR的面积逐渐减小。而注射胞内Ca²⁺激活剂(caffiene)后接种,HR的面积有所增加。进一步用胞内Ca²⁺通道抑制剂(herapin、RR和8-Br-cADPR)预处理,结果herapin对HR的影响呈浓度依赖型,而RR和8-Br-cADPR对HR没有明显作用。据此提出,胞内Ca²⁺可能参与小麦抵抗叶锈菌侵染过程中钙信号的形成,且这一过程主要通过IP₃途径完成。     

小麦单基因系TcLr19抗叶锈防卫反应的表达与叶锈菌侵染进程关系的初步研究

试验采用小麦单基因系TcLr19,感病对照Thacher(Tc)及叶锈菌小种366和165,利用组织化学方法,对接种后不同时间点叶锈菌在亲和和不亲和寄主上的发育情况进行观察,并对表现不同侵染型的TcLr19-叶锈菌组合中的2种防御酶苯丙氨酸解氨酶(PAL)和过氧化物酶(PO)的活性变化及发生过敏性死亡(HR)的细胞面积进行测定.结果表明,伴随着叶锈菌的侵染,TcLr19接种叶锈菌小种366(侵染型为0;)后PAL的活性分别在24,72 h出现高峰,PO活性在48 h达到最高峰,发生HR的细胞面积从接种后24 h逐渐增加直至96 h达到高峰;而接种叶锈菌小种165(侵染型为1)后2种酶活性变化及HR的变化和接种366具有相同趋势,但是前者的酶活性峰值低于后者,且发生HR的面积在96 h之前一直也小于后者.小麦对叶锈菌的抗性表达程度与防卫反应的表达强度呈正相关关系.     

小麦-秆锈菌互作中的激发子对小麦过敏性坏死反应和防御酶活性的诱导

小麦接种高度非亲和性的小麦秆锈菌后,在其细胞间隙液(IWF)中可能存在激发子.通过硫酸铵沉淀法将其分级,再将各分级沉淀蛋白溶液注射到高度非亲和性互作小麦叶片中,观察过敏性坏死反应(HR)和过氧化物酶(POD)及苯丙氨酸解氨酶(PAL)活性变化.结果表明:激发子成分主要集中在50%～80%硫酸铵沉淀蛋白部分中,能明显诱导叶片发生过敏性坏死反应;40 μg/mL的该分级沉淀蛋白溶液处理小麦叶片后,PAL和POD活性在早期已有显著增加,分别在诱导处理后36 h和60 h左右出现最高峰,较对照分别增加了37.47%和78.20%.     

Ca2+·CaM信使系统参与小麦抗叶锈病反应的初步研究

研究Ca2+.CaM是否参与小麦抗叶锈病反应的过程,为更深入了解小麦抗叶锈病的反应机制奠定基础。采用离体培养的方法测定小麦种子经CaM拮抗剂TFP(三氟拉嗪)、CPZ(氯丙嗪)和W-7(N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide)以及CaCl2预处理后小麦叶片接种叶锈菌后在不同时间点的酶活性。另外用实时定量PCR的方法检测小麦接种亲和小种和非亲和小种后CaM不同亚型基因的表达情况。试验结果表明:小麦叶片接种非亲和性叶锈菌后,TFP、CPZ和W-7浸种处理抑制了过氧化物酶(POD)、丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)和过氧化氢酶(CAT)活性的上升;小麦叶片接种亲和性叶锈菌后,CaCl2预处理加剧了过氧化物酶(POD)、丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)和过氧化氢酶(CAT)活性的上升。这说明Ca2+.CaM信使系统可能在小麦抗叶锈病过程中起着重要作用,并且不同的CaM亚型可能调控不同的抗病途径。     

小G蛋白Rab2基因参与小麦抗叶锈病反应的研究

为了解叶锈菌侵染小麦后小G蛋白Rab2基因的表达情况,明确其与抗病性的关系,从分子水平上探讨小麦的抗叶锈病机制。以普通六倍体小麦近等基因系TcLr1和叶锈菌小种05-22-64①和05-8-63①为试验材料,构建小麦亲和与非亲和组合,利用实时定量PCR技术对小麦小G蛋白Rab2基因的表达情况进行检测。结果表明:在小麦叶锈菌侵染过程中,Rab2基因主要在侵染的前期表达迅速,随着时间的推移表达量有所下降。非亲和叶锈菌菌株可以诱导小G蛋白Rab2基因表达量的升高,而亲和叶锈菌菌株抑制小G蛋白Rab2基因的表达。由此表明,小G蛋白可能与寄主和病原物的亲和程度有着直接的关系。     

钙处理对枇杷果实采后生理特性的研究

适当的钙处理可明显减缓枇杷果实的采后生理活力。试验结果表明：氯化钙喷施枇杷,果实Ca2+含量提高,呼吸高峰推迟出现,峰值降低;细胞膜透性、丙二醛（MDA）含量呈上升趋势,随钙浓度提高幅度下降且比对照低;钙调蛋白含量先上升后下降,峰值随钙浓度增大而上升,对照一直呈下降趋势;过氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性随贮藏时间延长逐渐上升后下降,钙浓度愈高幅度愈小;过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）等酶活性均呈上升趋势, PAL活性随钙浓度上升,效果愈明显,POD活性随着钙浓度上升,幅度变小,且均低于对照;同时发现钙浓度过高,果实出现轻微生理病害。说明用1.5%氯化钙对叶、果同时喷施能有效地减缓枇杷果实采后生理活动,又不至于发生生理病害。     

TaCDPK2基因在小麦与叶锈菌互作过程中的表达分析

在本实验室前期构建的非亲和互作的SSH文库基础上,从叶锈菌侵染的小麦叶片中发现在接种后8 h表现高表达量的CDPK2-EST。CDPKs即钙离子依赖蛋白激酶,是植物细胞应对各种生物和非生物胁迫过程中承接Ca2+流变化的重要因素。为进一步研究CDPK2在小麦与叶锈菌互作过程中的表达特性,采用RT-PCR和Western-Blotting技术分别在mRNA水平和蛋白质水平对小麦受叶锈菌侵染后不同亲和性组合中CDPK2的表达谱进行了检测。结果表明,小麦CDPK2基因受叶锈菌侵染诱导,不亲和组合在接种后4 h无论在mRNA水平还是蛋白质水平该基因均表现上调表达,而转录水平的表达量在接种后16 h降至对照水平;而在蛋白水平其表达量在接种16 h达到最大,之后又恢复至对照水平。亲和组合中该基因在接种后8 h在mRNA水平略有表达,在蛋白水平其表达量在接种后8 h和16 h有上调表达但其表达量低于不亲和组合,之后又趋于对照水平。这一结果表明,小麦CDPK2基因参与了小麦与叶锈菌的互作过程,并在该过程中对提高小麦抗叶锈能力有一定作用。这一结果为深入探讨小麦CDPK2基因在小麦抵抗叶锈菌侵染中的作用及作用机制奠定了基础。     

TaRanGAP2在小麦抵抗叶锈菌侵染中的作用

为研究TaRanGAP2在小麦抵抗叶锈菌侵染的HR诱发中的作用,阐明小麦抗叶锈病分子机制,为小麦抗叶锈病育种给予分子水平的指导.以小麦近等基因系TcLr26及其轮回亲本Tc分别与叶锈菌生理小种260组成不亲和组合(TcLr26×260)及亲和组合(Tc×260),生物信息学分析发现,TaRanGAP2的CDS全长为16...     

河北省又取得一批植保农药类科研成果

<正>(接上期)5.钙调素在小麦受叶锈菌侵染诱发的过敏性反应中的作用单位名称:河北农业大学评价单位名称:河北省教育厅该研究以小麦-叶锈菌互作体系为研究对象,利用小麦品种洛夫林10分别和叶锈菌生理小种260、165组成不亲和组合和亲和组合,试图查明CaM是否参与小麦抵抗叶锈菌     

氯钾离子共体诱导后黄瓜叶片内酶活性的变化

分别用浓度为0．2％,0．5％,1．0％,1．5％,2．0％的氯钾离子共体液,在黄瓜幼苗子叶期(子叶充分展开)和第一真叶期(第一真叶横宽5cm)进行2次诱导。然后对其第一真叶的POD,PPO,PAL活性进行测定。结果表明：不同浓度氯钾离子共体液处理后,POD,PPO,PAL活性均有不同程度的变化,变化趋势均为随时间的增加先升高、后降低,诱导后10d左右达到最大值,且极显著高于对照。试验还筛选出导致POD,PPO,PAL活性变化最大的氯钾离子共体液的浓度范围为0．5％～1．0％。     

冬枣锈病发生与叶龄及其解剖结构关系的研究

为探讨冬枣叶龄、叶片解剖结构与锈病侵染和发病程度的关系，对冬枣3种不同叶龄的叶片进行锈病接种试验，并对叶片组织解剖结构进行了测定。结果表明：3种叶龄叶片感病程度由低到高依次为：成熟叶< 长成叶<嫩叶，由此可见，成熟叶对锈病的抵抗力最强；3种叶龄叶解剖性状在角质层厚度、上表皮厚度、下表皮厚度、叶片厚度、栅栏组织厚度、海绵组织厚度、栅海比、叶片结构紧密度、叶片结构疏松度、气孔密度和气孔大小等指标有显著差异，但气孔开张结构性状差异不显著。文章筛选出了与冬枣锈病发生有关的叶片形态结构指标，为合理的控制冬枣锈病和筛选抗锈病冬枣优良单株的提供了理论依据。     

Exploring wheat landraces for rust resistance using a single marker scan

Marker-trait associations identified in diverse germplasm can be exploited in crop improvement programs. An attempt to establish such associations was made by evaluating 205 wheat landraces for stripe rust, leaf rust and stem rust responses in the field over three crop seasons. Diversity arrays technology was used to genotype the landraces and associations were identified using a single-marker scan. Sixty-eight markers were significantly associated with rust resistance. Several significantly associated loci coincided with the presence of known major genes or QTL for rust resistance. In contrast, many marker-rust response associations identified in this analysis for each of the three rust diseases uncovered new loci. Dual associations; stripe rust-leaf rust (1AL, 2BS, 2BL, 3DL, 5BS, 6BS and 7DL), leaf rust-stem rust (5BL) and stripe rust-stem rust (4BL and 6AS) resistance were also observed. These associations could enable a cost-effective targeted mapping of dual rust resistance. Some marker-trait associations identified in this study have been validated through genetic analyses and formal naming of resistance loci.     

Influence of development stage and host genotype on three components of partial resistance to leaf rust in spring wheat

Summary Latency period (LP), infection frequency (IF) and urediosorus size (US) of leaf rust were determined on primary leaves and young flag leaves of 18 spring wheat cultivars. A large growth stage effect and a large cultivar effect on all three components were observed. Partial resistance as measured by the three components was generally better expressed in the adult plant stage than in the seedling stage. Associated variation of the components was observed: long LP, low IF and small US tended to go together. The association was not complete, cultivars with clear deviations of this association for one of the components were found suggesting the existence of at least partly different genetic factors controlling the respective components. LP measured on flag leaves gave the most reliable results and, therefore, could best be used as a selection criterion in breeding programs for partial resistance.     

Transfer of rust resistance from Aegilops ovata into bread wheat (Triticum aestivum L.) and molecular characterisation of resistant derivatives

An interspecific cross was made to transfer leaf rust and stripe rust resistance from an accession of Aegilops ovata (UUMM) to susceptible Triticum aestivum (AABBDD) cv. WL711. The F₁was backcrossed to the recurrent wheat parent, and after two to three backcrosses and selfing, rust resistant progenies were selected. The C-banding study in a uniformly leaf rust and stripe rust resistant derivative showed a substitution of the 5M chromosome of Ae. ovata for 5D of wheat. Analysis of rust resistant derivatives with mapped wheat microsatellite makers confirmed the substitution of 5M for 5D. Some of these derivatives also possessed one or more of the three alien translocations involving 1BL, 2AL and 5BS wheat chromosomes which could not be detected through C-banding. A translocation involving 5DSof wheat and the substituted chromosome 5M of Ae. ovata was also observed in one of the derivatives. Susceptibility of this derivative to leaf rust showed that the leaf rust resistance gene(s) is/are located on short arm of 5M chromosome of Ae. ovata. Though the Ae. ovatasegment translocated to 1BL and 2AL did not seem to possess any rust resistance gene, the alien segment translocated to 5BS may also possess gene(s) for rust resistance. The study demonstrated the usefulness of microsatellite markers in characterisation of interspecific derivatives. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mature plant resistance of barley to barley leaf rust,another type of resistance

Summary Seedling and flag leaves of three barley cultivars were simultaneously inoculated with urediospores of barley leaf rust, race 1-2-1, and incubated at the same greenhouse bench. The inoculated leaves were harvested before urediospore formation was initiated. The volume of a large number of colonies was estimated by measuring colony area and colony depth by embedding the colony containing leaf segments into paraffin for microtome cutting. The colony volume was considerably smaller in flag leaves than in seedling leaves even in the extremely susceptible cultivar. On average the difference was about tenfold.     

Growth of wheat leaf rust colonies in susceptible and partially resistant spring wheats

Summary The average size of wheat leaf rust colonies, measured using epifluorescence microscopy was significantly larger in the highly susceptible genotype Morocco than in the susceptible genotype Kaspar and the partially resistant genotypes Westphal 12A, Akabozu and BH 1146. This was already so three days after inoculation. Colony growth in partially resistant genotypes was continuously retarded compared to colonies in the highly susceptible genotype Morocco. No evidence was found for an initial inhibition of the growth of colonies in partially resistant genotypes. In partially resistant genotypes formation of uredial beds and sporulating areas started at a smaller colony size than in susceptible genotypes. Wheat leaf rust colonies in primary leaves of all genotypes studied were much larger than colonies in flag leaves measured at the same number of days after inoculation. Growth and sporulation of not intertwined colonies was not influenced by either a high or a low number of neighbouring colonies.     

56个小麦品种（系）的苗期和成株抗叶锈鉴定

为了研究中国小麦品种中所携带的抗叶锈基因,对56个小麦品种（系）进行苗期接种推导其中所含有的抗叶锈基因,同时连续2年对供试材料进行田间成株抗叶锈鉴定。通过苗期基因推导结合分子标记辅助检测,结果表明,在36个小麦品种中共鉴定出Lr26、Lr34、Lr1、Lr2a、Lr11、Lr20、Lr30、Lr33和Lr44等9个抗叶锈基因,其中28个品种含有Lr26,Lr1和Lr20分别存在于6个品种中,4个品种含有Lr30,Lr11和Lr44各存在于2个品种中,Lr2a、Lr33和Lr34各自在1个品种中出现。经过2年的田间抗叶锈鉴定共筛选出46个慢锈品种。筛选到的这些苗期和成株抗病品种均可用于小麦持久抗叶锈品种的培育。     

Lack of durability of resistance to cereal rusts in wheat when selection is for complete resistance

Twenty-one bread-wheat entries were selected after careful screening for complete or near-complete resistance to yellow rust (Puccinia striiformis), stem rust (P. graminis), and leaf rust (P. recondita). In 1987, the 21 entries were intercrossed in a near-half diallel scheme. The resulting 190 F₂ populations were advanced to F₇ under selection for complete resistance to the three rusts and for good agronomic types. In 1992 the 21 parents and 140 selected F₇ lines were assessed for their resistance to the three rusts. Of the 21 parents, 12 showed a breakdown of yellow rust resistance, five a breakdown of stem rust resistance and two a breakdown of leaf rust resistance. In addition, several of the 140 selected F₇ lines, all still resistant in F₆, had become susceptible to one or more of the rusts. It appears that a progression towards more complex races, especially of yellow rust, is inevitable for the wheat-cereal rust patho-systems when the selection is for complete or near-complete resistance.     

Influence of wheat leaf position on leaf rust severity

Summary The relation between flag leaf position and leaf rust severity was investigated in field experiments. Different leaf angles were obtained by attaching ends of flag leaves to strings stretched at different heights along wheat rows. Leaves with angles between lamina and stem of 0° and 45° were significantly less diseased than leaves with horizontal and pendulous positions. In the experiment with seedlings, spore settling and uredia number were significantly lower on erect than on horizontal leaves. The influence of wheat leaf position changes on leaf rust severity was discussed. It has been suggested that breeding of wheat cultivars with erect leaves can improve their resistance to airborne pathogens.