小麦抗纹枯病QTL的抗性因素研究

发布时间：2018-05-28 03:41

本文选题：小麦纹枯病 + 数量抗病性　；参考：《中国农业大学》2017年博士论文

【摘要】：普通小麦(Triticum aesrivum L.)(下文简称小麦)在粮食安全中占有重要地位,由禾谷丝核菌(Rhizoctonia cerealis)所引起的纹枯病对小麦生产构成了严重威胁。例如,2015年我国小麦纹枯病流行面积将近1.4亿亩,造成了大量产量损失。对于该病害的防治,培育并利用抗病品种可以减少化学杀菌剂的使用,是最经济有效、安全环保的措施。目前,国内外在小麦种内尚未发现对纹枯病免疫的基因,但是从中鉴定的一些小麦品种(例如,CI12633、山红麦、Luke、AQ)其病情明显低于其它品种,表现出数量抗性的特点,这是由数量抗性位点(QuantitativeTrait Loci,QTL)控制的数量抗病性。众多研究表明,小麦抗病性位点的鉴定、克隆以及相关抗性因素研究对于后期的作物抗性育种实践具有重要意义。本实验室前期构建了小麦品种Luke与AQ杂交组合的高世代(F10)重组自交系群体(Recombinant Inbred Line,RIL),并从中鉴定并发表了7个在不同试验环境条件下稳定表达的抗纹枯病QTL(QSe.cau-1AS、QSe.cau-2BS、QSe.cau-3BS、QSe.cau-4AL、QSe.cau-5DL、QSe.cau-6BL、QSe.cau-7BL)(Chenetal.2013)。在此基础上,本文研究目的是,进一步探讨这7个抗病QTL与植株形态性状、茎秆木质素含量、及2个防卫反应基因的关系,从而明确这7个QTL的抗病原因,哪些抗性点具有非小种专化性或非菌株专化性而哪些是通过诱导生理互作发挥抗性作用,从而更好地在育种实践中利用它们的抗病性。为此,本研究进行了以下4个试验:第一,在前期工作基础上,进一步完善Luke ×AQ染色体DNA标记遗传连锁图谱,将DNA标记数目增加到613个,RIL数目增加到266个,为小麦植株形态性状QTL染色体定位提供了准确可靠的基因型数据;第二,于田间种植上述266个RIL,观测它们的植株形态性状(共15个),得到了共两个生长期的5次生物重复试验的表现型数据,基于表现型数据和遗传图谱的基因型数据,进行了形态性状QTL的染色体定位,并比较这些形态性状QTL与上述7个抗纹枯病QTL之间的染色体位置关系,分析二者的遗传相关性;第三,从934个高代RIL(F10)筛选得到了8个关键RIL,其中7个RIL各自只含有1个不同的抗纹枯病抗性位点,第8个RIL不含有任何纹枯病抗性位点,将上述8个RIL种植在不利于小麦纹枯病的发生且没有发现该病发生的自然条件田间,于开花后取样测定了植株茎秆组成型木质素的含量,比较上述RIL组成型木质素含量的差异,从而分析各个抗性位点与木质素的关系;第四,于温室种植上述8个RIL,在拔节期对其接种纹枯菌,接菌5天后取其植株基部茎段,采用qRT-PCR方法测定各个RIL的过氧化氢酶基因转录量和病程相关蛋白-1基因的转录量,分析上述7个抗性位点与这两个防卫基因表达的关系。主要得到了如下4个方面的结果:(1)在上述7个抗纹枯病QTL中,有3个位点(QSe.cau-1AS、QSe.cau-2BS、QSe.cau-6BL)与植株形态性状相关,可能并不直接抗病,而是通过控制植株形态特征,影响植株群体内湿度等小气候因素,不利于纹枯菌侵染蔓延,预期不存在小种专化性或菌株专化性问题,具有更为持久的抗病性;(2)其中的1个抗性位点(QSe.cau-7BL)与茎秆组成型木质素含量相关,它可能是通过提高木质素含量,从而提高茎杆机械强度发挥抗病作用,因此,预期也不存在小种专化性或菌株专化性问题;(3)有3个抗性位点(QSe.cau-2BS、QSe.cau-3BS、QSe.cau-4AL)与过氧化氢酶基因转录量和病程相关蛋白-1基因转录量相关,二者是植物抗病机制代表性标志物,因此,这3个抗纹枯病QTL可以作为进一步研究小麦抗纹枯病抗性机制的切入点或试验材料;(4)还有1个位点(QSe.caau-5DL)与上述各个因素均无确定的相关性,需要进一步试验研究其抗病原因。
[Abstract]:Common wheat (Triticum aesrivum L.) (hereinafter referred to as wheat) occupies an important position in grain security. The sheath blight caused by cereal nucleocacal fungus (Rhizoctonia cerealis) poses a serious threat to the production of wheat. For example, the epidemic area of Wheat Sheath Blight in China in 2015 will be nearly 140 million mu, resulting in a large amount of yield loss. The prevention, cultivation and use of resistant varieties can reduce the use of chemical fungicides, which is the most economical and effective, safe and environmental protection. At present, there are no genes in the wheat species immune to sheath blight, but some wheat varieties (such as CI12633, red wheat, Luke, AQ) identified in this field are obviously lower than other varieties, showing that the disease is obviously lower than that of other varieties. The characteristics of quantitative resistance, which are controlled by the quantitative resistance loci (QuantitativeTrait Loci, QTL), have shown that the identification, cloning and related resistance factors of wheat resistance loci are of great significance to the later crop resistance breeding practice. In the early stage of the laboratory, the wheat variety Luke and AQ were constructed. In the high generation (F10) of the high generation (Recombinant Inbred Line, RIL), 7 anti sheath blight QTL (QSe.cau-1AS, QSe.cau-2BS, QSe.cau-3BS, QSe.cau-4AL, QSe.cau-5DL, QSe.cau-6BL) in different experimental environment conditions were identified and published. The purpose is to further explore the relationship between the 7 disease resistant QTL and plant morphological characters, the content of stem lignin and the 2 defense response genes, so as to clarify the resistance causes of the 7 QTL, which resistance points have non small specific or non specific specificity, and which are to play resistance by inducing interplant interaction, and thus better in breeding. The following 4 experiments were carried out in this study. Firstly, on the basis of previous work, the Luke x AQ chromosome DNA marker linkage map was further perfected, and the number of DNA markers increased to 613, and the number of RIL increased to 266, which provided accurate and reliable for the chromosomal location of the morphological character of wheat plant morphological characters. Second, second, we planted 266 RIL in the field, observed their plant morphological characters (a total of 15), and obtained the expressive data of 5 biological repeated tests in two growth periods. Based on the genotypic data of the phenotype data and genetic map, the chromosomal location of the morphological character QTL was carried out and the morphological character QTL was compared. The relationship between the chromosomal location of the 7 anti sheath blight QTL and the genetic correlation between the two was analyzed. Third, 8 key RIL were obtained from 934 high generation RIL (F10), of which 7 RIL had 1 different resistance sites for resistance to sheath blight and eighth RIL did not contain any sheath blight resistance loci, and 8 RIL was planted in unfavorable conditions. The occurrence of Wheat Sheath blight was not found in the natural condition of the disease. After flowering, the content of the plant stem type lignin was measured, and the difference of the content of the RIL type lignin was compared, and the relationship between the resistance loci and lignin was analyzed. Fourth, the above 8 RIL were planted in the greenhouse and inoculated at the jointing stage. The Rhizoctonia of Rhizoctonia Rhizoctonia was taken for 5 days. The transcriptional amount of catalase gene and the transcriptional amount of the course related protein -1 gene of each RIL were measured by qRT-PCR method. The relationship between the 7 resistance loci and the expression of the two defense genes was analyzed. The main results were as follows: (1) in the above 7 anti sheath blight disease QTL 3 loci (QSe.cau-1AS, QSe.cau-2BS, QSe.cau-6BL) are related to plant morphological characters. They may not be directly resistant to disease, but by controlling plant morphological characteristics, affecting the humidity and other microclimate factors in the plant group, which is not conducive to the infection and spread of Rhizoctonia. It is expected not to exist in small species specialization or strain specialization, which is more lasting. Disease resistance; (2) 1 of the resistance loci (QSe.cau-7BL) were related to the content of the stem component lignin. It may be by raising lignin content and improving the mechanical strength of the stem to play the disease resistance. Therefore, it is expected that there is no small specialization or strain specialization; (3) there are 3 resistance loci (QSe.cau-2BS, QSe.cau-3BS, QSe.cau). -4AL) is related to the transcription of catalase gene and the transcriptional amount of course related protein -1, and the two is the representative marker of plant disease resistance mechanism. Therefore, these 3 anti sheath blight QTL can be used as a breakthrough point or experimental material to further study the resistance mechanism of Wheat Sheath blight. (4) there are 1 loci (QSe.caau-5DL) and the above factors. No definite correlation was found, and further study on the cause of disease resistance was necessary.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S435.12

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