Changes in concentrations and transcripts of plant hormones in wheat seedling roots in response to Fusarium crown rot

Fusarium crown rot(FCR) is a soilborne disease causing severe yield losses in many wheat-growing areas of the world. Diseased plants show browning and necrosis of roots and stems causing white heads at maturity. Little is known about the molecular processes employed by wheat roots to respond to the disease. We characterized morphological, transcriptional and hormonal changes in wheat seedling roots following challenge with Fusarium pseudograminearum(Fp), the main pathogen of FCR. The pathogen inhibited root development to various extents depending on plants' resistance level. Many genes responsive to FCR infection in wheat roots were enriched in plant hormone pathways. The contents of compounds involved in biosynthesis and metabolism of jasmonic acid, salicylic acid, cytokinin and auxin were drastically changed in roots at five days post-inoculation. Presoaking seeds in methyl jasmonate for 24 h promoted FCR resistance, whereas presoaking with cytokinin 6-benzylaminopurine made plants more susceptible. Overexpression of TaOPR3, a gene involved in jasmonic acid biosynthesis, enhanced plant resistance as well as root and shoot growth during infection.

Fusarium pseudograminearum and F.culmorum affect the root system architecture of bread wheat

Yield losses of bread wheat due to crown rot can be more severe when drought conditions occur during the grain-filling period.Root architecture characteristics are important for soil exploration and belowground resource acquisition and are essential for adaptation to water-limited environments.Traits such as root angle,length and density have been strongly associated with acquisition efficiency and contribute to yield stability of the crop.The impact of crown rot pathogens on wheat root architecture is poorly understood.We examined differences in root angle,length and number,as well as dry root weight of the crown rot-susceptible bread wheat cultivar,Livingston inoculated with one of two crown rot pathogens Fusarium culmorum or Fusarium pseudograminearum in a transparent-sided root observation chamber.Significant adverse impacts on plant health and growth were revealed by visual discolouration of the leaf sheaths;fresh and dry shoot weight;leaf area of the oldest and the youngest fully expanded leaf and leaf number.Values of most recorded root system measurements were reduced when inoculated with either F.culmorum or F.pseudograminearum.In contrast,root angle was increased in the presence of F.culmorum but was not significantly changed by F.pseudograminearum.The development of whiteheads and grain losses in bread wheat caused by crown rot have previously been associated with blockages of the vascular systems.The method employed here was able to identify differences in the pathogen impacts on roots,which were not detected using previous systems.This research indicates that in the presence of F.culmorum and F.pseudograminearum infection,not only reductions in the size and biomass of the shoot system but also changes in the length,biomass and architecture of the root system could play an important role in yield loss.

Root and Foot Rot Diseases of Winter Wheat Grown in Conventional and Organic Systems

The object of the study was fungous diseases occurring on roots, leave sheaths and stem base of winter wheat in the two opposing cropping systems (organic and conventional). The observations were made in vegetation periods (2007-2009) in the fields of winter wheat in northern Poland. Every year on each plot of compared farming systems root rot occurred (Fusarium spp., Gaeumannomyces graminis and other fungi). For the period of 3 years the degree of disease injury on the roots of winter wheat grown in the conventional system in the vegetation period increased, while in the organic one remained on pretty the same level. On average a lot more affected roots, especially in the flowering stage, occurred on the winter wheat grown in the conventional system. Fusarium foot rot (Fusarium spp.) developed on the wheat during the entire vegetation period. It was the most dangerous root and foot rot disease (the highest indexes of injury). The mean degree of disease injury on leave sheath was on pretty the same level in the two farming systems, although in investigated vegetation periods differed a lot, whereas at the bases of stems the pathogen was on the higher level on the wheat in the conventional system. Also eyespot (Tapesia yallude) developed in the entire vegetation period of the winter wheat, but its intensity was much lower than in case of fusarium foot rot. Leave sheaths of the wheat grown in the conventional system were slightly stronger affected than those grown in the organic system. In the flowering stage the intensity of the disease in both farming systems became equal, while in the wax maturity it was considerably higher in the conventional system. Sharp eyespot (Rhizoctonia spp.) appeared relatively late and occurred only in two years of investigation. The intensiveness of the disease was definitely higher on the organic plots. Among the affected roots, taken in the stem elongation stage, from the organic system 28 cultures of fungi were isolated, and from the conventional one 24 colonies. Cereals pathogenic fungi amounted 35.8% of isolates obtained from the organic system and as many as 66.7% from the conventional system. Among the affected roots, taken in the flowering stage, from the organic system 68 cultures of fungi were isolated in all, and from the conventional one 25 colonies. Cereals pathogenic fungi amounted 38.2% of isolates obtained from the organic system and 56.0% from the conventional system. Among the affected stem bases, taken in the wax maturity stage, from the organic system 56 cultures of fungi were isolated in all, and from the conventional one 52 colonies. Cereals pathogenic fungi amounted 48.4% of isolates obtained from the organic system and 53.6% from the conventional system. In the case of all root and foot rot diseases of wheat grown in the organic system, an advantageous influence of greater biodiversity and number of various fungi species living in root proximity was noticed as opposed to the conventional system.

麦根腐平脐蠕孢引起新疆小麦根腐病的病原鉴定及其生物学特性分析

【目的】研究新疆小麦根腐病病原菌种类和生物学特性,为制定该病有效防控措施提供科学依据。【方法】采用组织分离法对麦根腐病株病原菌进行分离培养,选择新疆试验区的代表性菌株检测致病力,结合形态学及分子生物学方法鉴定病原菌种类,采用生长速率法测定主要生物学特性。【结果】试验区代表菌株(KS1-3、YL26、TC30及ML26)均具有致病性;经鉴定该病病原菌为小麦根腐平脐蠕孢Bipolaris sorokiniana。PDA培养基最为适合菌菌株的生长,温度5~35℃、pH值4~10条件下均可生长,最适温度30℃,最适pH值7,对光照不敏感,最佳碳源为可溶性淀粉、蔗糖,最佳氮源为牛肉膏、蛋白胨。【结论】新疆小麦根腐病病原为麦根腐平脐蠕孢B.sorokiniana,其主要生物学物性与多数菌物相类似,较喜温喜光。

荧光假单胞杆菌P_(2-5)菌株对小麦全蚀病的抑制作用

室内测定了荧光假单胞杆菌P2-5菌株对小麦全蚀病菌9826菌株的拮抗作用。结果表明,P2-5菌株对小麦全蚀病菌具有较强抑制作用,抑制效果和防治效果分别为67％和59％,高于化学杀菌剂烯唑醇(特普唑)处理的效果。研究表明P2-5菌株可以致使病菌菌丝畸变。应用双抗标记法测定了P2-5菌株在小麦根系中的定殖情况,结果表明,该菌可以在小麦根系定殖。

抗全蚀病、根腐病的转PgPGIP1基因小麦的获得与鉴定

全蚀病和根腐病是小麦(Triticum aestivum)重要的土传真菌病害。PgPGIP1是人参(Panax ginseng)的一种多聚半乳糖醛酸酶抑制蛋白,可以抑制部分病原真菌分泌的多聚半乳糖醛酸酶的活性。本研究人工合成了PgPGIP1基因,并构建PgPGIP1基因的单子叶植物表达载体pA25-PgPGIP1,通过基因枪介导法将其转入小麦品种扬麦18中。对转PgPGIP1基因的T0至T4代植株进行PCR、RT-PCR和Q-RT-PCR分析,并对其全蚀病和根腐病抗性进行鉴定。结果表明,PgPGIP1基因能够在4个转基因小麦株系中遗传、转录与表达。与未转基因的小麦扬麦18相比,4个转基因小麦株系对全蚀病与根腐病的抗性明显提高,说明PgPGIP1表达增强了转基因小麦对全蚀病与根腐病的抗性。

几种生物制剂对小麦根腐病菌的毒力

为探索生物制剂对小麦根腐病的防控效果,采用菌丝生长法测定了6种生物制剂对禾谷镰刀菌、刺腐霉菌和小麦离蠕孢菌的毒力。结果表明,申嗪霉素、乙蒜素和春雷霉素具有良好的抑菌效果,其中申嗪霉素的毒力最强,对禾谷镰刀菌、刺腐霉菌和小麦离蠕孢菌的EC50值分别为0.350 2 mg·L-1、0.864 5mg·L-1和0.134 1mg·L-1,乙蒜素对刺腐霉菌和小麦离蠕孢菌的EC50值分别为2.957 3 mg·L-1和2.342 7mg·L-1,春雷霉素对刺腐霉菌和禾谷镰刀菌的EC50值分别为0.864 5 mg·L-1和5.090 9mg·L-1。室内盆栽试验表明,申嗪霉素和乙蒜素对禾谷镰刀菌的防治效果显著优于春雷霉素,防治效果分别为75.73%和74.68%;乙蒜素对刺腐霉菌的防治效果最好,防效为86.28%;申嗪霉素和乙蒜素对离蠕孢菌的防效分别为87.68%和83.25%。综上所述,申嗪霉素和乙蒜素能有效抑制禾谷镰刀菌、刺腐霉菌和小麦离蠕孢菌三种病原菌的生长,对小麦根腐病防治具有很大应用潜力。

甘肃省小麦根病病原种类及致病性研究

１９９１～１９９３年，从甘肃庆阳、武威等地区的７个县（市）采集小麦生育期病根标样１７３４份，进行室内病原分离及致病性测定。结果表明：引起省内小麦根病的病原种类有全蚀病菌小麦变种（Ｇａｅｕｍａｎｎｏｍｙｃｅｓｇｒａｍｉｎｉｓｖａｒ．ｔｒｉｔｉｃｉ）、全蚀病菌一新变种（Ｇ．ｇｒａｍｉｎｉｓｖａｒ．ｓｐ）、麦根腐病菌（Ｂｉｐｏｌａｒｉｓｓｏｒｏｋｉｎｉａｎａ）、小麦生离蠕孢菌（Ｂ．ｔｒｉｔｉｃｉｃｏｌａ）、黄色镰刀菌（Ｆｕｓａｒｉｕｍｃｕｌｍｏｒｕｍ）、禾谷镰刀菌（Ｆ．ｇｒａｍｉｎｅａｒｕｍ）、早熟禾根腐镰刀菌（Ｆ．ｐｏａｅ）和丝核菌（Ｒｈｉｚｏｃｔｏｎｉａｓｐ）等１０种病原菌，其中全蚀病菌分离频率最高（４８．３％）、致病力最强（病指６０．２～１００）。

黄淮地区主推小麦品种对根腐病抗性的初步鉴定与评价

为了给根腐病的防治和抗病育种工作提供依据,以小麦根腐病病原菌麦根腐离蠕孢(Bipolaris sorokiniana)LK030093分离物为接种菌株,对黄淮麦区主推的89个小麦品种进行了室内盆栽苗期抗性和田间病圃成株期抗性鉴定,并采用病情指数法进行了抗性评价。结果表明,供试小麦品种中没有免疫和高抗品种;在室内盆栽接种鉴定中,仅郑麦9962表现为抗病,平安8号和周麦24表现为中抗,淮川916、西农919等33个品种表现感病,平安3号、济麦23等53个品种表现高感,抗病、中抗、感病和高感品种所占比例分别为1.12%、2.25%、37.08%和59.55%;在田间病圃成株期鉴定中,洛麦22、泛麦5号表现为抗病,郑麦9962、阜麦936等19个品种表现为中抗,周麦27、济麦20等35个品种表现为感病,兰考906、石麦12等33个品种表现为高感,抗病、中抗、感病和高感品种所占比例分别为2.25%、21.35%、39.33%和37.08%。可见,黄淮麦区主推品种对小麦根腐病的整体抗性较差,需要尽快加强抗病资源筛选和抗病育种工作。

6种杀菌剂对小麦叶斑根腐病菌的毒力测定

筛选高效的防治药剂并研究出其配套的田间防治应用技术是防治小麦根腐病的重要措施,而通过不同杀菌剂对病原菌的毒力测定分析,可为田间防治药剂的筛选提供重要的参考依据。此研究采用生物测定的方法,研究了6种化学药剂对小麦叶斑根腐病菌菌丝生长的抑制作用。结果表明,不同药剂对病原菌生长的影响不同,世高对菌丝生长的抑制作用最显著,在质量浓度为40mg/L时抑制率达94.9%;其次为唑醚·代森联、丙森锌、福美双、多菌灵和代森锰锌,在该浓度下对菌丝生长抑制率依次为89.5%、86.3%、48.2%、40%和37.8%。对病原菌菌丝生长抑制效果最好的世高对病原菌孢子萌发同样具有强烈的抑制作用,抑制萌发中浓度为6.45mg/L,可在生产中继续合理使用。

抗根腐病的转GmPGIP3基因小麦扬麦18的获得与鉴定

GmPGIP3是大豆的一种多聚半乳糖醛酸酶抑制蛋白,能够特异性地抑制部分病原真菌内切多聚半乳糖醛酸活性,从而减弱病原菌对植株的侵害。利用基因重组技术构建了GmPGIP3基因的单子叶植物表达载体pA25-GmPGIP3,通过基因枪介导法将pA25-GmPGIP3转入小麦品种扬麦18中。对转GmPGIP3基因扬麦18的T0至T2代植株进行PCR、Southern杂交、半定量RT-PCR和荧光定量Q-RT-PCR分析,并对根腐病进行抗性鉴定。结果表明,GmPGIP3已转入扬麦18,并在转基因小麦中遗传、转录和表达;与受体材料相比,5个GmPGIP3过表达的转基因小麦株系对根腐病的抗性有明显提高。

小麦根腐病菌鉴定及其生物学特性测定

分离鉴定小麦根腐病菌 ,并对其进行生物学特性测定 ,结果表明 ,小麦根腐病菌属于半知菌亚门平脐蠕孢属麦根腐平脐蠕孢 (Bipolarissorokiniana(Sacc .)Shoemakey)。该菌生长的最适温度为 30℃ ,最适 pH值为 7,最适培养基为PDA ,6 0℃ 5min为致死温度。分生孢子在水滴中才能萌发 ,萌发的最适 pH值为 7,最适温度为 2 5℃ ,在供试的营养液中 。

河北省小麦土传病害的发生现状及防治措施

小麦土传病害是严重影响小麦产量的根部病害。河北省小麦土传病害的种类主要包括小麦全蚀病、小麦纹枯病和小麦根腐病。详细介绍了3种土传病害的发生特点、病原菌特点及防治方法等,旨为控制小麦土传病害的发生提供参考。

芽孢杆菌JPC-2的营养竞争测定及其对小麦根部病害的防治效果

对营养竞争拮抗测定方法进行了改进,对接法将芽孢杆菌JPC-2与小麦纹枯病菌接种于大豆麦麸(SWB)培养基上,JPC-2可在SWB培养基上迅速扩展并完全抑制小麦纹枯病菌的菌丝生长。田间试验表明,芽孢杆菌JPC-2液体菌剂(107cfu/mL,1∶100)处理种子对小麦纹枯病的冬前期防效高于扬花期防效,防治效果为61.9%,高于3%苯醚甲环唑包衣处理(用量为种子质量的0.3%);对小麦根腐病的防治效果可达46.8%,与空白对照差异显著(p<0.05);并使小麦增产73.5%,高于3%苯醚甲环唑种衣剂。芽孢杆菌JPC-2固体菌剂(106cfu/mL,225kg/hm2)沟施于土壤,再播种液体菌剂包衣(107cfu/mL,药种比1∶30)的小麦种子,对小麦纹枯病菌的冬前期防效为68.9%,扬花期防效为59.7%,小麦增产38.9%,与0.2%戊唑醇种衣剂(1∶50)增产效果相当。

小麦根腐病成株期品种抗性记载方法的探讨

小麦品种或株期对根腐病的抗病性,宜在小麦灌浆中期,调查记载平均病斑型、感病叶普遍率和平均严重率。应用品种平均严重率和高度抗病品种平均严重率的比值,参照5种不同抗病类型(HR,R、M、S、HS)标准对照品种的平均严重率比值范围,可确定品种的抗病或感病状况。上述参数可作为年度间品种抗病类型分析的依据。

木醋液对小麦根腐病致病菌及小麦发芽的影响

本研究采用菌丝生长速率法测定不同浓度木醋液对小麦根腐病菌的抑菌活性,并采用不同浓度的木醋液培养小麦,测定小麦发芽势、发芽率及生长情况,旨在明确不同浓度木醋液对小麦根腐病3种致病菌(腐霉菌、平脐蠕孢菌和禾谷镰刀菌)的抑菌作用,以及对小麦发芽和生长情况的影响,最终筛选出防治小麦根腐病的最佳木醋液使用浓度。结果发现,0.80%以上浓度的木醋液能够完全抑制3种致病菌的菌丝生长。其中木醋液浓度为0.10%时对腐霉菌菌丝生长的抑制率达到84.28%;木醋液浓度为0.40%时,对平脐蠕孢菌菌丝生长的抑制率达到81.56%;木醋液浓度为0.60%时对禾谷镰刀菌菌丝生长的抑制率达到83.78%。不同浓度的木醋液对小麦发芽及生长也有影响,浓度大于0.50%时,小麦发芽势和发芽率均呈下降趋势,浓度大于1.00%时,小麦的根长和地上部分长度都显著减小。因此,采用木醋液防治小麦根腐病的最适浓度为0.60%。

小麦全蚀病为害新特点及其治理对策研究

经４年研究证明，进入９０年代以来，山东省小麦全蚀病有两个新的为害特点，其一是全蚀病发生区有所扩大，已遍及全省１７个市地，发病县区占全省农业县区的８５％，病情仍然严重；其二是病地由以往的全蚀病单一为害，发展为近年来的以全蚀病为主、多种根腐性病害同田甚至同株侵染为害。其形成原因主要包括长期推行小麦、玉米一年两熟制，偏施氮肥，缺少有机肥和磷、钾肥，以及普遍种植感病品种等。经试验、示范，提出“三改一治”的农业生态综合治理对策，推广应用效果显著，平均防效为８５．８％。

BvGLP1过表达增强了转基因小麦对根腐病的抗性

类萌发素蛋白(germin-like protein,GLP)是一类含有cupins结构域的糖蛋白,在植物基础抗性等方面起着重要作用。本研究人工合成了甜菜GLP基因BvGLP1,并利用基因重组技术构建了受韧皮部特异表达启动子RSS1P驱动的BvGLP1基因单子叶植物表达载体pA20-RSS1P::BvGLP1。通过基因枪介导法将其转入小麦品种扬麦18中,对转基因扬麦18的T0至T3代植株中BvGLP1进行了PCR、半定量RT-PCR和荧光定量QPCR检测,并对转基因小麦进行根腐病和纹枯病抗性鉴定。结果表明,BvGLP1已转入转基因小麦扬麦18,并能在转基因小麦中遗传、转录表达;5个转BvGLP1基因小麦株系的根腐病抗性比受体品种扬麦18有显著提高,说明BvGLP1过表达增强了转基因小麦对根腐病的抗性。

小麦腐霉根腐病原鉴定Ⅰ

2015年冬小麦返青期,山东省青岛市、临沂市的冬小麦出现缺苗断垄现象,叶片出现萎蔫症状,植株矮小,生长不良,毛细根上出现似开水烫过样水渍状病斑,重者小麦根系及茎基部变褐。本研究对其病原菌进行分离培养、致病性测定、形态学观察及分子生物学鉴定。结果表明,引起两地冬小麦根腐病(称为腐霉根腐病)的病原菌为刺腐霉(Pythium spinosum),该病原菌菌落白色,菌丝发达,分枝繁茂。该研究结果可为冬小麦腐霉根腐病防治提供科学依据。

不同施肥处理对小麦根际土壤真菌多样性及根腐病的影响

设置不施肥(T1)、习惯施肥(T2)、推荐施肥(T3)和有机肥替代50%化肥(T4)4个处理,旨在研究不同施肥对小麦(Triticum aestivum L.)根际土壤真菌多样性及根腐病的影响。结果表明,不同施肥处理小麦根系活力从大到小依次为T4、T3、T2、T1。T3处理平均产量为5 878.95 kg/hm^2,比T2处理仅减少66.45kg/hm^2,比T4处理增产1 111.80 kg/hm^2。施用化肥降低了土壤pH以及真菌群落的丰富度和多样性,改变了真菌群落结构。禾谷镰刀菌的相对丰度从大到小依次为T2、T4、T3、T1,麦根腐平脐蠕孢的相对丰度和根腐病病情指数均表现为T4较低。因此,在推荐施肥量下,适当降低有机肥替代化肥的比例才能保障产量,同时降低根腐病发病率。