【作者】 黄强；

【导师】 李晚忱； 何康来；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2010， 硕士

【摘要】 玉米粗缩病是一种由植物黑条矮缩(RBSDV)病毒引起的毁灭性病害,近年来在黄淮海夏玉米区,特别是套播或晚春播、早夏播玉米发生为害严重,成为该区玉米上的重要病害。本研究通过人工在健康水稻苗上饲养繁殖传毒介体灰飞虱(Laodelphax striatellus),转移至感染了水稻黑条矮缩病的水稻苗饲喂无毒飞虱,在灰飞虱度过循回期之后,获得带水稻黑条矮缩病毒(RBSDV)灰飞虱。利用水稻黑条矮缩病毒(RBSDV)特异性引物,采用RT-PCR的方法,扩增水稻黑条矮缩病毒的特异性片段510 bp,进行病原物鉴定。然后用带毒灰习虱侵染玉米幼苗,在玉米粗缩病发病过程的4个时期,即发病初期、症状加深期、症状明显期、症状完全期分别取样玉米幼嫩茎尖组织,采用ELISA方法检测玉米植株幼嫩茎尖组织中的内源激素生长素(IAA)、赤霉素(GA)、脱落酸(ABA)和玉米素核苷(ZR)的变化情况。结果显示,病株IAA含量水平逐渐下降,在每个取样时期含量为128.00 ng/g fw、114.20 ng/g fw、113.27 ng/g fw和108.75 ng/g fw,分别比对照下降了27.6%、28.0%、32.3%和33.5%；ZR含量仅在接毒后25 d显著低于对照,病株玉米素核苷含量比对照下降了34.4%；GA含量在正常苗含量总的趋势是逐渐下降,病株随病程发展先较对照显著增加,再下降,在介体接毒后15 d病株GA含量显著高于对照39.5%；病毒侵染造成脱落酸含量先下降后上升,在介体接毒后15、25和45 d时病株脱落酸含量比对照显著降低59.6%、72.1%和49.0%。试验结果表明,RBSDV的侵染引起玉米4种内源激素的比例失衡,导致植株畸形生长。IAA含量下降,ZR相对保持不变,使C/A(细胞分裂素与生长素的比值)升高,引起玉米顶端优势丧失,并导致了细胞分化的紊乱,促使叶脉和茎节韧皮部细胞的扩增,出现脉突、植株矮缩、心叶无法抽出等生长畸形症状。GA含量显著增加,ABA显著下降,且二者呈显著的负相关。植株中ABA的非正常减少,扰乱了其正常的防御机制,使抗病性降低,RBSDV得以迅速在植株体内复制、增殖,GA的迅速增加,导致非正常分化的叶脉细胞等的增殖,粗缩病症迅速表现。更多还原

【Abstract】 Maize rough dwarf disease (MRDD) caused by the rice black-streaked dwarf virus (RBSDV), a planthopper transmitted virus disease, is one of the most destructive diseases on maize in China, especially it is has frequently been outbreak on the interplanting, late-spring planting or early-summer planting maize in the Huang, Huai, and Hai rivers velley for the last a few years.In this study, laboratory reared planthopper Laodelphax striatellus Fallen on rice was transferred on rice that was infected by rice black-streaked dwarf virus (RBSDV) after circulative period to get the vector with RBSDV. Identification of RBSDV was performed by special DNA fragments 510bp based on RT-PCR with RBSDV species specific primers.Reference to Di pad level approach, with the rice black-streaked dwarf virus vecter (Laodelphax striatellus Fallen) feeding in the 2 leaves stage of Zheng 958 maize, After 15d, we obtain infected RBSDV maize. Molecular characterization indicates that the maize was infected rice black-streaked virus.Pathogenic process of maize rougf dwarf diease (MRDD) was divided into four stages base on the symptom on the plants, i.e. early perceptible stage, developing stage, distinct stage, completely appearent stage. The quantitfication of endogenous hormones, including the gibberellins (GA), indole-3-acetic acid (IAA), abscisic acid (ABA) and zeatin riboside (ZR) in young shoot tip tissue of maize Zhengdan 958 were done by ELISA method. In the infecting process of RBSDV, the contents of IAA decreased gradually and they were 128.00 ng/g fw,114.20ng/g fw,113.27ng/g fw, 108.75ng/g fw at the four stages of the sympts in the infected plants, respectively, with a decrease of 27.6%、28.0%、32.3%、33.5% compared to the control. The ZR content was only significantly lower than that of healthy plants at the symptom developing stage with a decrease of 34.4% to control. The levels of GA contents in the healthy maize plants were decreased as long with the plant developments. However, the contents of GA were increased at the symptom early perceptible stage and developing stage, then decreased. It was significantly increased to 39.5% compared to the control at the symptom early perceptible stage. In contrast with GA, ABA levels of RBSDV infested plants firstly decreased and then increased. However, they all were lower than that of healthy plants throughout the infection process, and were significantly decreased by 59.6,72.1, and 49.0% campared to the control at the symptom early perceptible, developing, and completely appearent stages.These results suggest that the infection of RBSDV on maize upset the balances of endogenous hormones, which stunts the plant development, i.e. causeing rough dwarf. of the increase of IAA and decrease of ZR were resulted in the value of C/A increased, which lead to the loss of apical dominance, slow elongation, horizontal growth (rough dwarf), and even leaf could not be extended. In addition, the decreased IAA would interfere the normal cell differentiation. The contents of GA and ABA were negatively correlated significantly. The unusual decrease of ABA interferes in the maize plant resistance to the RBSDV, the virus are significantly regenerated. In addition, the increase of GA in the plants accelerates the development of unsual differentiated cells of leaf vein and stem, which resulted in the symptom rough dwarf appearance.更多还原