【作者】 王建锋；

【导师】 康振生；

【作者基本信息】 西北农林科技大学 ， 植物病理学， 2010， 硕士

【摘要】 小麦条锈病是我国小麦安全生产最严重的威胁之一,病原菌为小麦条锈病菌(Puccinia striiformis West. f.sp. tritici)。该菌是一种活体寄生的、可远程气流传播的植物病原真菌,因气温和寄主缺乏在我国小麦主产区不能越夏,需要借助气流远程传播在数百到数千公里的范围内完成灭绝-再定殖循环,其越夏区群体对其完成周年循环和物种存续有着特殊重要的意义。陇南、川西北是条锈菌重要的越夏区之一,同时,由于该地区地形条件复杂,条锈菌在该区域内的川区、河谷地带可完成周年循环,因此,其被认为是我国小麦条锈菌流行区系中最为重要的核心区,它们不仅是菌源基地,而且还可能是新小种的主要策源地。目前,各地区条锈菌小种组成常被用为菌源区间传播的佐证之一,但小种组成不能作为流行区划的基本依据。利用传统的调查观察的方法对三省流行体系的推断需要分子遗传学研究的证实和完善,而且对该地区间的菌源传播关系还没有深入的研究。本研究以甘肃、陕西和四川三省的小麦条锈菌群体为研究对象,采用SSR标记进行分子群体遗传学分析,在研究各省小麦条锈菌群体遗传结构的基础上,分析三省小麦条锈菌的传播关系,为条锈菌的流行区划提供佐证。同时对陕、甘、川三省小麦条锈菌群体遗传的多样性、群体遗传结构特点及其演化过程进行系统的分子生态学分析。得出以下结果:1.四川省小麦条锈菌群体遗传多样性比较丰富,地区之间存在明显的差异,川西北和四川盆地的种群遗传多样性相对较高,而四川西南部和四川东南部的种群遗传多样性较低。四川小麦条锈菌群体存在一定的遗传分化,地区间的遗传变异仅占14.92%,群体间的遗传变异占总变异的23.06%,群体内遗传变异占60.02%,遗传变异主要存在于群体内部。基因流和共享基因型从分子水平证实了四川小麦条锈菌在地区间的传播,且川西北和四川盆地之间的菌源交流最为广泛。2.陕西省小麦条锈菌群体具有较高的遗传多样性,地区间无显著差异。条锈菌群体具有较低的遗传变异性,地区间遗传变异占12.26%,群体间10.88%,群体内76.86%,遗传变异主要存在于群体内部。基因流证实了小麦条锈菌在陕西省各地区间存在广泛的交换或短距离的移动,关中和陕南两个地区条锈菌群体存在显著的基因交流。3.甘肃省小麦条锈菌表现出很丰富的遗传多样性,这可能与其特殊的地理环境条件、小麦的栽培方式及品种有关。其中,陇南和天水地区的条锈菌遗传多样性高于平凉地区。其遗传分化程度很低。遗传分化系数(Gst)为0.17,群体内变异占总变异的83.0%。甘肃小麦条锈菌群体存在一定的基因流,各地区之间的基因流水平存在显著的差异,其中天水与平凉的基因流较强,天水与陇南、陇南与平凉次之,各个地区间菌源交流广泛。4.陕、甘、川三省的小麦条锈菌种群中,陇南种群、天水种群、四川盆地种群具有相对较高的遗传多样性,而川西南种群和川东南种群的遗传多样性水平相对较低。结果显示,三省小麦条锈菌群体具有丰富的SSR基因型,其中陇南、天水和平凉种群的基因型频率最高。三省小麦条锈菌群体具有较低的遗传变异性,遗传变异主要来自于群体内部。陕、甘、川三省总的小麦条锈菌基因流(Nm)为1.23,表明三省小麦条锈菌存在一定的菌源交流。更多还原

【Abstract】 Stripe rust (or yellow rust) of wheat (Triticum aestivum), caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat in China. The fungus is an obligate biotrophic pathogen. Spores of it could be spread by wind in long distance, so making epidemics across large areas. Since Longnan and northwest of Sichuan is one of the most important over-summering areas of P. striiformis f. sp. tritici in China, the objective of this study was to determine genetic structure of P. striiformis f. sp. tritici populations in this region with TP-M13-SSR technique. The main results are summarized as following:1. Genetic diversity for the pathogen population from northwest of Sichuan and Sichuan Basin were much higher than that from other regions. Genetic differentiation was also investigated. The results showed that interregional genetic variation accounted for 14.92% of the total, while interpopulational variation 23.6% and intrapopulational variation 60.02%. Moreover, our molecular data on gene flow and genotype confirmed the migration of pathogen populations among regions in Sichuan, in particular, between northwest of Sichuan and Sichuan Basin.2. Stripe rust of wheat population in Shaanxi Province had a high genetic diversity, no difference between the different regions. Stripe rust populations had low genetic variability, genetic variation between regions accounted for 12.26%, while interpopulational variation 10.88%, 76.86% within populations, genetic variation exists within groups. Gene flow confirmed there is widespread throughout the range of exchange or short-distance movement in Shaanxi Province. Southern of Shaanxi and Guanzhong groups had significant gene flow.3. Genetic diversity of the population from Longnan and Tianshui were higher than that from Pingliang region. Genetic differentiation of it was so lower. The results showed that Gst is 0.17, intrapopulation variation 83%. Our molecular data on gene flow confirmed the migration of pathogen populations among regions in Gansu Province. In particularly, gene flow is stronger between Tianshui and Pingliang than other regions.4. Genetic diversity of the population from Longnan population, Tianshui population and Sichuan Basin population is higher than others’population in Shaanxi Province, Gansu Province and Sichuan Province. Result showed that SSR genetype of the stipe rust from three provinces was rich.更多还原