【作者】 陈贵华；

【导师】 张少英；

【作者基本信息】 内蒙古农业大学 ， 植物学， 2009， 博士

【摘要】 甜菜是世界上重要的糖料作物,在生产中甜菜病害较多,其中甜菜丛根病是甜菜生产中的毁灭性病害,在世界广泛而迅速地蔓延。该病是由甜菜坏死黄脉病毒（Beet necrotic yellow vein virus,BNYVV）引起的,以多粘菌（Polymyxa betae）为传播媒介的一种土壤传播病害。近年来,国内外研究主要集中在甜菜坏死黄脉病毒基因组、多粘菌及其作用模式上,而关于甜菜抗丛根病的作用机制及其抗病信号转导途径目前尚未见报道,为解决和防治甜菜丛根病,本文分别以甜菜抗病、感病品种为试验材料,探讨了甜菜抗丛根病信号转导机制及其信号转导途径,重点分析了SA、H₂O₂、Ca²⁺作为信号分子的作用及其信号转导过程,目前取得的主要研究结果如下:1、研究了细胞壁中H₂O₂与甜菜抗丛根病的关系。结果表明,在BNYVV作用下,甜菜抗病品种细胞壁H₂O₂含量较大幅度升高,大量的H₂O₂激活了甜菜细胞抗氧化系统,提高甜菜抗丛根病的能力;H₂O₂诱导了HRGP基因的表达,甜菜细胞壁中羟脯氨酸（hyp）含量升高,提高了甜菜对丛根病的抗性;细胞壁中木质素大量积累,提高了甜菜自身的抗病性。综合分析可见,细胞壁中H₂O₂作为抗病信号物质在甜菜抗丛根病中起重要作用,可作为甜菜抗丛根病的一个信号分子。2、通过研究BNYVV对甜菜内源SA含量及其它相关指标的影响,明确了信号分子SA在甜菜抗丛根病中的作用及其作用路径。结果显示,BNYVV侵染后甜菜抗病品种块根SA含量明显升高,显著高于感病品种;叶片SA含量升高幅度也较明显,但其峰值明显低于块根中SA的含量,推断甜菜块根可能是产生SA的初始部位,通过长距离运输到达叶片。大量积累的内源SA,使甜菜块根中H₂O₂含量明显升高,高浓度的SA与H₂O₂,激活病程相关蛋白基因的表达,产生大量的病程相关蛋白（几丁质酶、β-1,3-葡聚糖酶）;甜菜块根中PAL活性升高,使木质素大量合成,提高甜菜对丛根病的抗性。综合分析可见,在BNYVV作用下,甜菜内源信号分子SA含量升高,SA促进H₂O₂在植物中大量积累, H₂O₂可作为另一个信号分子,激活甜菜的抗病防御系统,激活与抗病相关的基因的表达,提高甜菜抗丛根病性。说明,SA是甜菜抗丛根病重要信号分子之一。3、通过用Ca²⁺、CaM抑制剂分别处理田间及实验室种植的甜菜抗病、感病材料,进行CaM含量及其它相关抗病指标的测定,研究信号分子Ca²⁺在甜菜抗丛根病中的作用及其作用路径。结果表明,在BNYVV作用下,甜菜细胞中CaM含量与Ca²⁺浓度变化相趋势一致,甜菜细胞中的Ca²⁺浓度升高,激活CaM活性,Ca²⁺与其受体CaM结合,形成Ca²⁺-CaM系统。Ca²⁺-CaM系统可通过调控甜菜下游防御系统,提高甜菜抗丛根病性;通过对抗氧化酶系统的调控,清除活性氧,从而减轻了BNYVV对甜菜的伤害,提高了甜菜抗丛根病的能力;Ca²⁺-CaM系统可通过调控可溶性蛋白质的含量,增强代谢,提高甜菜对丛根病的抗性,Ca²⁺-CaM系统在甜菜抗丛根病信号转导过程中起重要作用。本课题其它信号分子的研究工作正在进行中。更多还原

【Abstract】 Sugar beet（Beta vulgaris L.） is an important sugar crop in the world,but its yield and quality are attacked severely by many diseases.Sugar beet rhizomania disease is the best severious in the sugar beet.It caused by Beet necrotic yellow vein virus and transmitted by the soil-borne parasite Polymyxa beta. For soluting rhizomania disease ,The mechanism of resistance to Rhizomania was investigated in sugar beet.The signal function of the signal transduction introduction of SA、H₂O₂ and Ca²⁺ as signal molecule and signal transduction process were attracted more attention also studied.The results showed as follows:1. Effect of Rhizomania on antioxidant system（Superoxide dismutase,SOD;Peroxidase POD）and Hydrogen peroxide（ H₂O₂）、hyp、lignin of sugar beet cell wall were studied.The result showed that the content H₂O₂ was higher than that of the normal growth condition; Under the infected of Rhizomania,SOD activity、POD activity、the content of lignin and hyp of resistant varieties were higher than susceptible varieties.This result showed : there exist a close relationship between resistance to Rhizomania and the content H₂O₂ of cell wall on sugar beet.2. The salicylic acid plays an important role in plants disease resistance.Effects of rhizomania on the content of salicylic acid, pathogenesis-related protein,H₂O₂,lignin and Catalase（CAT） activity, Phenyllalanine ammonialyase （PAL） activity of sugar beet were studied.The result showed that the content salicylic acid, H₂O₂,pathogenesis-related protein, lignin were higher than that of the normal growth condition;Under the infected of rhiaomania, Catalase（CAT） activity, Phenyllalanine ammonialyase （PAL） activity of resistant varieties were higher than susceptible varieties.Catalase（CAT） activity, Phenyllalanine ammonialyase （PAL） activity.This result showed :salicylic acid is the one of signal transduction .3. Effects of 3 inhibitors of Ca²⁺ （EGTA,LaCl3 and W7） on the content oCalmomdulin （CaM）,antioxidant system,Superoxide radical （O2-） production rate, H₂O₂ and soluble protein content were studied in sugar beet,cultivated in rhizomania contaminated soil and infected by Beet necrotic yellow vein virus.The results showed that the regular of the change Ca²⁺ is same with CaM;SOD activity,PODactivity, Catalase（CAT） activity,Ascorbic acid peroxidase（APX） activity and soluble protein content decreased while O2- production rate increased. It indicated a close relationship between resistance to rhizomania and Ca²⁺- CaM.The other signal functions in resistance to rhizomania are going on.更多还原