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论文题名(中文):

 山西玉米大斑病菌生理小种鉴定及苗期抗性评价体系建立    

作者:

 吉佩    

学号:

 S20172215    

保密级别:

 公开    

论文语种:

 chi    

学科代码:

 090401    

学科名称:

 农学 - 植物保护 - 植物病理学    

学生类型:

 硕士    

学位:

 农学硕士    

学校:

 山西农业大学    

院系:

 农学院    

专业:

 植物病理学    

研究方向:

 植物生理病理及分子病理    

第一导师姓名:

 王建明    

第一导师学校:

 山西农业大学    

论文完成日期:

 2020-06-11    

论文答辩日期:

 2020-06-06    

论文题名(外文):

 Study on the Population Structure of Exserohilum turcicum and the Establishment of Seedling Resistance Evaluation System in Shanxi Province    

关键词(中文):

 Exserohilum turcicum Ht抗性基因 生理小种 遗传多样性 苗期抗性评价体系    

关键词(外文):

 Exserohilum turcicum Ht resistance gene physiological race genetic diversity indoor seedling resistance evaluation criteria    

论文文摘(中文):

近年来,玉米大斑病(Northern corn leaf blight,NCLB)在山西省各产区频繁发生,严重影响了当地的玉米产量。目前防治玉米大斑病最经济有效的方法是选种抗病品种。由于玉米大斑病菌生理分化明显,小种变化复杂,而且毒性小种频率的上升容易导致抗病品种丧失抗性,所以明确山西省各玉米产区大斑病菌生理分化和遗传分化情况,对抗病品种的选育和该病害的有效防治具有重要的科学意义。此外,品种抗病性鉴定是抗病品种选育的一个关键环节,目前主要采用田间抗性鉴定,但其鉴定周期长、受环境影响大等因素,影响了品种抗性鉴定的科学性和准确性。因此,建立一种简便易行、快速准确,且受环境影响小的室内苗期抗病性鉴定方法,是目前玉米抗病性鉴定急需解决的一项技术难题。为此,本研究主要对山西玉米大斑病菌的生理小种、遗传多样性和室内苗期抗性鉴定方法进行了研究,旨在明确山西省玉米大斑病菌的生理小种种类、分布及其遗传分化情况,并初步建立玉米苗期抗性评价体系,为培育抗病品种、抗性鉴定和玉米大斑病的有效防治提供理论基础和科学依据。主要研究结果如下:

山西省玉米大斑病菌生理小种种类及其分布

本研究采用Ht单抗性基因鉴别寄主法,在2017~2018年采自山西省32个县市的玉米罹病叶片上分出185株玉米大斑病菌(Exserohilum turcicum),从中鉴定出0、1、2、3、N、12、13、1N、2N、3N、123、12N、13N、23N和123N,共15个生理小种。其中,123N为山西省优势小种,1、N、3N、23N和123N号为山西省主要致病群体。且不同地区小种分布情况总体表现为晋南地区>晋北地区>晋中地区,其中忻州最多,长治最少。185个菌株对Ht1、Ht2、Ht3和HtN这4个Ht单抗性基因的毒力频率分别是51.89%,51.35%,51.89%和71.89%,对双抗性基因组合、三抗性基因组合和四抗性基因组合的毒力频率分别为69.73%、43.24%和16.22%。综上所述,山西省各地区玉米大斑病菌生理分化现象明显,不同地区小种分布情况也存在较大差异,4种Ht单抗性基因的抗病品种已不能有效的防治该病害的发生和危害。

山西省玉米大斑病菌ISSR遗传多样性分析

本试验利用优化后体系和程序,采用7条ISSR引物对山西省不同地区的24

 

株玉米大斑病菌进行PCR扩增,结果显示,7条ISSR引物共扩增出89条条带,多态性为95.51%。24株玉米大斑病菌的遗传相似系数在0.326~0.955之间,平均遗传相似系数为0.725,以0.82划分为6个类群,说明山西省不同地区玉米大斑病菌间存在丰富的遗传多态性,且菌株多态性与菌株的地理来源无明显相关性,但与生理分化有一定关系。

玉米苗期抗大斑病评价体系的建立

本试验采用单因素分析法和苗期与田间鉴定结果吻合度分析法,对4种接种方法和3个苗期抗性评价指标进行对比分析,结果显示,菌饼法、棉花菌液法、喷雾法和涂抹法病情指数分别为40.00、52.59、62.92和86.67,其中,喷雾法病情指数相对较高且操作简单,无死苗现象,为最优苗期接种方法。病斑数、病斑面积和面积比3个评价标准的苗期鉴定结果与田间鉴定结果的吻合度分别为43.33%、60.00%和73.33%。其中,面积比评价标准的苗期鉴定结果与田间结果的吻合度最高,为最佳苗期抗性鉴定评价标准。因此,苗期抗性鉴定最优接种方法为喷雾法,最佳苗期评价标准体系指标为面积比。

文摘(外文):

In recent years, Northern corn leaf blight has frequently occurred in various production areas in Shanxi Province, which seriously affected the local corn production. At present, the most economical and effective way to control the northern corn leaf blight is to select resistant varieties. Since the physiological differentiation of Northern corn leaf blight pathogen is obvious, the race changes are complex, and the increase in the xx frequency of toxic race easily leads to the loss of resistance of disease-resistant varieties, it is of important scientific significance to clarify the type, distribution and diversity of pathogen for breeding of resistant varieties and effective control of the disease. In addition, the identification of variety resistance is a key step in the selection of resistant varieties, whereas the long identification cycle and large environmental impact of the current field resistance identification method  has greatly affected the scientificity and accuracy of variety resistance identification  . Therefore, the establishment of a simple, fast and accurate method for   disease resistance identification in indoor seedling stage is a technical problem that needs to be solved urgently in disease resistance identification of maize variety. To this end, this study mainly studied the physiological races and genetic diversity of Exserohilum turcicum pathogens in Shanxi, and explored the indoor seedling resistance identification methods of maize, aiming to clarify the physiological race types, distribution and genetic polymorphism of Exserohilum turcicum in Shanxi Province, and the establishment of effective seedling resistance identification evaluation standards, provide the theoretical basis and scientific basis for breeding disease-resistant varieties, resistance identification and effective control of the northern corn leaf blight. The main findings are as follows:

1. Physiological race types and distribution of Exserohilum turcicum in Shanxi Province

In this study, a total of 15 physiological races, including 0, 1, 2, 3, N, 12, 13, 1N, 2N, 3N, 123, 12N, 13N, 23N and 123N, was identified by the race-specific single Ht resistance gene identification host method  from 185 strains of Northern corn leaf blight pathogen (Exserohilum turcicum) isolated from diseased leaves of corn collected from 32 counties and cities in Shanxi Province from 2017 to 2018. The 123N was the dominant race in Shanxi Province, accounting for 16.22%. Among them, the physiological races No. 1, N and 123N were mainly distributed in Xinzhou, accounting for 60.00%, 45.83% and 46.67% of the total respectively; The physiological race No. 23N was mainly distributed in Yuncheng, accounting for 44.00% of the total. The virulence frequencies of the 185 strains against the four single Ht resistance gene Ht1, Ht2, Ht3, HtN, and combinations of double, triple and quadruple resistance genes were 51.89%, 51.35%, 51.89%, 71.89%, 69.73%, 43.24% and 16.22%, respectively. In summary, the physiological differentiation of Exserohilum turcicum in various areas of Shanxi Province is obvious, and the distribution of various races in different areas of Shanxi is quite different. The disease resistance of the variety with a single Ht resistance gene has been significantly reduced, and the disease resistance varieties that rely on these four single Ht resistance genes have been unable to effectively control the occurrence and harm of the disease.

2. Optimization of ISSR-PCR amplification system and ISSR genetic diversity analysis of Exserohilum turcicum in Shanxi Province

In this experiment, the ISSR-PCR amplification system and program of  Exserohilum turcicum were optimized. Using the optimized amplification system and program, the PCR amplification results of 24 strains of Exserohilum turcicum from different regions of Shanxi Province using seven ISSR primers showed that a total of 89 bands were amplified  with a polymorphism of 95.51 %. The genetic similarity coefficients of 24 Exserohilum turcicum ranged from 0.326 to 0.955, the average genetic similarity coefficient was 0.725, and were divided into six groups with 0.82, indicating that there are abundant genetic polymorphisms among Exserohilum turcicum in different areas of Shanxi Province. In addition, the polymorphism of the strain was related to the geographical origin and physiological differentiation of the strain, but there was no positive correlation.

3. Establishment of indoor seedling resistance evaluation system

In this experiment, the single factor analysis method was used to compare four inoculation methods. Then, the consistency analysis  of  resistance identification results obtained at indoor and field was used to compare and analyze  three resistance evaluation indexes at the seedling stage and their classification standards. The results showed that the disease index of seedling inoculated through mushroom cake method and cotton liquid spraying method, spraying method and smearing method were 40.00, 52.59, 62.92 and 86.67, respectively. Among them, the disease index of spraying method was relatively high and easy to operate, which was the best method of inoculation at seedling stage. Three evaluation standards of resistance identification based on the number of disease spots, the area of disease spots and the area ratio  were established. According to these  evaluation standards, the results of the indoor seedling test and field test were 43.33%, 60% and 73.33%, respectively.  Among them, the evaluation results of the indoor seedling stage using the area ratio as the indicator of evaluation index has the best coincidence with the field test, which is the best evaluation standard of resistance evaluation at the indoor seedling stage. Therefore, the best inoculation method for resistance identification at the seedling stage is the spray method, and the best resistance evaluation index for the indoor seedling stage is the area ratio.

中图分类号:

 S432.1    

馆藏号:

 Y10621    

开放日期:

 2020-06-11    

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