麦田生态系统中麦长管蚜与赤霉病的生态调控模型构建与机理研究

发布时间：2018-01-16 12:32

本文关键词：麦田生态系统中麦长管蚜与赤霉病的生态调控模型构建与机理研究　出处：《西北农林科技大学》2016年博士论文　论文类型：学位论文

【摘要】：全世界小麦(Triticum aestivum L.)的种植总面积超过21,500万公顷,在麦田生态系统中,小麦往往被不同种类的有害生物依次或同时进行为害。有害生物种类很多,麦长管蚜和赤霉病等就是其中非常重要的小麦病虫害,麦蚜的刺吸危害以及赤霉病引起的穗腐,严重地影响小麦的品质和产量,并威胁着人类的粮食安全。目前,大多数研究仅围绕其中一种虫害或一种病害展开,难以发现麦田生态系统中物种间调控模型和机制。应用这种调控模型去调节麦田系统中病虫害的发生数量和程度,以此降低危害程度、减少化学农药的使用,是满足人类日益增长粮食需求的重要途径之一。因此,本研究以小麦和不同种类病虫害组建麦田生态亚系统:挖掘并转化小麦本身具有的抗性基因以培育高产抗虫害种质资源、利用小麦的诱导抗性、寻找降低病原菌致病性的相关基因和基因敲除等方法让致病基因沉默,以此构建调控模型,分析其调控机理,以期为麦田生态系统有害生物生态调控提供理论依据。研究得出以下重要结论:1在麦田生态系统中,小麦已经进化出众多调控策略以降低麦长管蚜的危害水平。本研究证明小麦品系XN98-10-35生态调控策略为耐害性;将已获得6个小麦的表达序列标签(Expressed Sequence Tag),通过比对分析发现,其中一个候选基因的功能与小麦的光合作用密切相关,被定于小麦7D染色体上,与本课题组通过分子标记方法研究的抗性基因定位的结果一致。所以,XN98-10-35主动提高光合作用是其调节并抵御麦长管蚜危害的重要分子机制之一。2在麦田生态系统中,叶蝉种群动态高峰早于麦长管蚜种群,因此叶蝉取食后的小麦是如何调控后续麦长管蚜种群动态对构建调控模型和害虫种群数量调节具有重要意义。本研究以麦长管蚜生命表参数的变化为衡量指标,研究前期叶蝉危害的小麦如何调节麦长管蚜生长发育与繁殖以及种群动态。研究结果表明:受到叶蝉危害后的感蚜小麦品种Bobwhite和Leguan均不是适合后期麦长管蚜取食的宿主,即小麦受到叶蝉危害后,对麦长管蚜产生了诱导抗性,显著地影响其生长发育和繁殖,进而调控其种群动态。3小麦赤霉病的流行主要由禾谷镰刀菌(Fusarium graminearum Schwabe)引起,而且禾谷镰刀菌可以摄取环境中合成生长素的相关底物来生物合成生长素,以提高其致病性。然而鲜有禾谷镰刀菌体内合成生长素途径的相关报道,因此研究麦田生态系统中禾谷镰刀菌采用哪些途径合成生长素,是该病害生态调控的关键点之一。本研究结果表明:添加至培养液中可能的生长素合成前体L-色氨酸、吲哚-3-丙酮酸、吲哚-3-乙胺(TAM)和吲哚-3-乙腈(IAN)等,除了L-色氨酸的代谢产物为生长素的类似物色醇外,其他的三种均可以被用来合成生长素,证明禾谷镰刀菌可利用多个底物经由多条途径合成生长素,为其生态调控提供新的方向。4禾谷镰刀菌在侵染过程中,可以分泌大量的呕吐毒素(15-ADON)毒污小麦籽粒,有效降低其含量在粮食的安全生产上具有非常重要的作用。本研究探索添加不同浓度的生长素以及生长素合成前体对禾谷镰刀菌15-ADON合成能力的影响,以期寻找可以抑制15-ADON合成的化合物与适用的浓度。结果显示:仅1 mM IAN对禾谷镰刀菌的野生菌株合成生物毒素15-ADON带来严重的影响。为深入探究1 mM IAN调控禾谷镰刀菌产生毒素机理研究发现:高浓度IAN可以有效抑制菌丝的伸长速度和数量。因此,添加1 m M IAN是麦田生态系统降低禾谷镰刀菌产生毒素的调控策略之一。5探究生长素合成过程是生态调控禾谷镰刀菌侵染过程的关键,因此,本研究根据前人Microarray实验的结果,选择12个可能参与合成生长素或色醇的候选基因,利用USER Friendly Clone和农杆菌介导转染的方法,对其进行替换突变。最终成功获得9个候选基因的突变体。添加相应底物之后,发现有4个候选基因的突变株合成色醇或生长素的能力被抑制:即FGSG_01285、FGSG_05295、FGSG_01572或FGSG_09834参与了生物合成合成色醇或生长素的途径。与此同时,这些突变株15-ADON分泌的能力也受到了极大的抑制,显示出利用沉默基因技术也是麦田生态系统防止镰刀菌产生毒物的调控策略。然而,还有3个候选基因的突变株却极大的促进15-ADON的合成,表明这些基因可能是调控禾谷镰刀菌产生毒物的关键基因。6为了进一步明确L-色氨酸可以促进15-ADON分泌的机理,分析前人所得禾谷镰刀菌添加L-TRP之后全局基因表达的研究结果,发现添加至培养液的L-色氨酸,仅有少量参与生物合成色醇,而大部分的L-色氨酸却被降解为能源和碳源,由此添加L-色氨酸并不能作为生态调控禾谷镰刀菌的手段。综上所述,选择种植优质、高产、耐害性小麦品种,配合喷施较高浓度生长素或者IAN是麦田生态系统中调控麦长管蚜和赤霉病的有效途径和方法。
[Abstract]:World wheat (Triticum aestivum L.) of the total planting area of more than 215 million hectares, in the wheat field ecosystem, wheat is often harmful organisms of different types of sequentially or simultaneously make damage. Many pest species of wheat aphid and wheat scab is one of very important pests, wheat aphids sucking harm and the scab caused by ear rot, seriously affecting the quality and yield of wheat, and threaten human food security. At present, most studies only around one pest or a disease, it is difficult to find crop among species in an ecosystem model and regulation mechanism. Using this control model to adjust the amount and degree of occurrence pest catcher system, in order to reduce the harm degree, reduce the use of chemical pesticides, is one of the important ways to meet the growing human demand for food. Therefore, the study on Wheat And different kinds of diseases and insect pests of crop establishment sub ecosystem: Mining and transformation of resistance genes to wheat has to cultivate high-yield pest resistant germplasm resources, the use of induced resistance in wheat, and seek to reduce pathogenic related genes and gene knockout method to silence genes, in order to construct the regulation model, analyze its regulation mechanism in order to provide theoretical basis for wheat field ecosystem ecological pest control. The research draws the following conclusions: 1 in the wheat field ecosystem, wheat has evolved many harm level control strategy to reduce the wheat aphid. This study proved that XN98-10-35 ecological control strategy of wheat lines for tolerance; acquired expression sequence label 6 wheat (Expressed Sequence Tag), through the comparison analysis, which is closely related with the function of a candidate gene of wheat photosynthesis, was scheduled to be small Wheat chromosome 7D, and the research group through the study on molecular markers of resistance gene detection method of the consistency of the results. Therefore, XN98-10-35 is actively improving photosynthesis regulating and one of the important molecular mechanism against aphid damage.2 in wheat field ecosystem, the insect population dynamic peak earlier than the wheat aphid population, therefore after the wheat leafhopper feeding is how to regulate the following wheat aphid population dynamics has important significance for the construction of regulation model and pest population regulation. Based on the change of Sitobion avenae aphid life table parameters as the index, to study how to regulate the wheat growth and reproduction and population dynamics of aphids before period of wheat leafhopper harm. The results show that by leafhopper harm of aphid wheat varieties Bobwhite and Leguan were not suitable for the late wheat aphid feeding host, namely wheat by leafhopper harm, to The wheat aphid induced resistance, significantly affect the growth and reproduction, and regulating the population dynamics of.3 Wheat Scab Epidemic mainly by Fusarium graminearum (Fusarium graminearum Schwabe) caused by Fusarium graminearum, and related substrates to synthesize auxin uptake in the environment to the biosynthesis of auxin, in order to improve its pathogenicity. However, few reports of Fusarium graminearum in auxin biosynthesis pathway, so the study of wheat field ecosystem in Fusarium graminearum by the ways in which synthetic auxin, is one of the key points of the disease ecological regulation. The results of this study show that: added to the culture of auxin synthesis precursor L- tryptophan may acid, indole -3- indole pyruvic acid. -3- ethylamine (TAM) and indole -3- (IAN), but was similar for alcohol metabolite L- tryptophan to auxin, three can be used in other The synthesis of auxin, Fusarium graminearum that can use multiple substrate through a plurality of pathway for the synthesis of auxin, its ecological regulation provides new direction.4 of Fusarium graminearum in the infection process, vomiting can secrete large amounts of toxic poison pollution (15-ADON) grain wheat, reduce its content has a very important role in the production of food safety the. This study explores adding different concentrations of auxin and auxin precursors of Fusarium graminearum 15-ADON synthesis effect, in order to find 15-ADON can inhibit the synthesis of compounds with suitable concentration. The results show that the serious impact is only 1 mM IAN of Fusarium graminearum wild strains of synthetic biology toxin 15-ADON. In order to explore the regulation of IAN 1 mM of Fusarium graminearum toxin producing mechanism of discovery: elongation rate and quantity of high concentration of IAN can effectively inhibit the mycelium. Therefore, adding 1 m M IAN is a wheat field ecosystem reduced Fusarium graminearum toxin production control strategy of.5 on auxin synthesis process is the key of ecological regulation, Fusarium graminearum infection process and therefore, according to the previous results of Microarray, 12 may be involved in the synthesis of growth hormone or tryptophol candidate genes, using the method of USER Friendly Clone and agricultural Agrobacterium mediated transfection, the mutation was eventually successful. 9 candidate gene mutants. After adding the corresponding substrate, there are 4 candidate gene mutations or auxin synthesis tryptophol ability was inhibited found: FGSG_01285, FGSG_05295, FGSG_01572 or FGSG_09834 is involved in the biosynthesis of auxin synthesis of alcohol or color at the same time, the mutant strain 15-ADON secreted ability has also been greatly suppressed, showing the silencing of gene technology is the crop ecological system The control strategy to prevent Fusarium toxins. However, there are 3 candidate gene mutant was greatly promoted the synthesis of 15-ADON, suggesting that these genes may be the key regulatory gene.6 of Fusarium graminearum producing poison in order to further clarify the mechanism of L- tryptophan can promote the secretion of 15-ADON, analysis of results obtained with Fusarium graminearum after adding an L-TRP global gene expression, that added to the culture of L- color liquid ammonia acid, only a small amount of alcohol and L- involved in the biosynthesis of color, but most of the tryptophan was degraded as carbon and energy sources, thus adding L- tryptophan and not as a means of ecological control of Fusarium graminearum. In summary, selection of planting quality tolerance, high yield, wheat varieties with high concentration of auxin or IAN spray is an effective way and method of wheat field ecosystem in the regulation of wheat scab long Guan Yahe.

【学位授予单位】：西北农林科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S435.12

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