【作者】 张静；

【导师】 王小蓉；

【作者基本信息】 四川农业大学 ， 果树学， 2016， 硕士

【摘要】 中国樱桃(Cerasus pseudocerasus (Lindl.)G. Don)起源于我国,栽培历史长达3000年,是我国古老的栽培果树之一,也是世界四大主栽樱桃品种之一。中国樱桃广泛分布于我国各生态地理区域。其中,栽培中国樱桃主要分布于我国的四川盆地、云贵高原、秦岭、华北平原及部分华东平原地区,野生资源则相对集中地分布于四川盆地、云贵高原和部分秦岭地区。中国樱桃树姿秀丽、花朵清香、果型果色丰富,群体间和群体内均展现出丰富的表型多样性,具有较高的观赏价值和经济价值。然而,近年来由于生境破坏、品种替代和管理粗放,中国樱桃遗传资源已经严重流失。虽然中国樱桃种质资源的相关研究逐渐增加,但主要集中于局部地区的或单一类型(栽培或野生)的遗传多样性研究,不能全面地真实地反映出我国中国樱桃种质资源的现状。因此,本实验基于中国樱桃自身基因组开发出17对SSR引物用于采自我国11省(直辖市)60余县市的542份中国樱桃(338份中国樱桃地方种质和204份野生资源)的遗传多样性分析,以期为中国樱桃种质资源的保护及栽培品种的改良创新提供一定的理论依据。主要结果如下：1、基于中国樱桃自身基因组开发的SSR引物的筛选与评价本研究中所选出的17对引物具有较高的多态性、特异性、扩增效率和较好的重复性(An=0.137,I=0.808,PIC=0.367)。通过与甜樱桃基因组比对后,其中7对引物可以匹配到参考基因组的6条染色体上。此外,17对引物包含了二核苷酸、三核苷酸、四核苷酸、五核苷酸和六核苷酸重复序列,其中以二核苷酸(64.71%)和三核苷酸(27.27%)重复序列为主。综上所述,本实验筛选出的17对引物能有效地应用于中国樱桃遗传多样性的研究之中。2、中国樱桃遗传多样性分析利用上述所得的17对多态性高、重复性好的引物对338份栽培中国樱桃和204份野生中国樱桃按类型和不同地理分布分别进行了遗传多样性分析。结果表明栽培中国樱桃遗传多样性(Na=5:294, Ne=1.645, Ar=3.407, He=0.332,I=0.641)低于野生中国樱桃(Na=5.824,Ne=2.120,Ar=6.928, He=0.490,I=0.986)。不同地理分布的分析结果显示,栽培中国樱桃遗传多样性最高的两个区域为云贵高原(He=0.355,I=0.672)和秦岭(He=0.355,I=0.649),随后依次为华北华东平原(He=0.318,I=0.557)和四川盆地及川内周边地区(He=0.241,I=0.483)而野生中国樱桃遗传多样性由高到低分别为四川盆地(He=0.491,I=0.986)秦岭(He=0.429,I=0.793)和云贵高原(He=0.411,I=0.764)。3、中国樱桃群体遗传结构与遗传分化分析STRUCTURE分析、NJ聚类分析和主成分分析(PCoA)结果显示,中国樱桃可粗略分为栽培中国樱桃和野生中国樱桃两大类群,但在野生与栽培资源重叠区域表现出了较为频繁的基因渗透。在此基础上,栽培中国樱桃类群又可划分为四川盆地及川内周边和云贵高原类群及秦岭和华北华东平原两大亚类群,与地理分布表现出一定的相关性。野生群体内部则表现出明显的混合、交叉,没有明显的群体结构。此外,秦岭群体内部发生较大分化,推测秦岭为两大亚类群的过渡地带。由分子方差分析(AMOVA)结果可知,中国樱桃的遗传变异主要存在于群体内部。整体而言,中国樱桃内部存在中度的遗传分化(FS7=0.098,Nm=2.298)。野生与栽培群体间检测到中度的分化(FST=0.095,Nm=2.382)。栽培组内部存在相对较大的遗传分化(FST=0.131,Nm=1.655)。野生组内部仅存在轻微的遗传分化(FST=0.041,Nm=5.771),表明野生群体内部频繁的基因交流和共享的遗传信息减缓了群体间的遗传分化。更多还原

【Abstract】 As one of the worldwide cherry species, Chinese cherry(Cerasus pseudocerasus (Lindl.) G. Don)is native to China and has been cultivated more than 3000 years. It inhabits wide eco-geographic regions in China. Currently. Chinese cherry landraces are widely distributed among Sichuan Basin. Yunnan-Guizhou Plateau, QinLing Mountains, North China Plain and partial East China Plain, and wild resources are mainly distributed among Sichuan Basin. Yunnan-Guizhou Plateau and partial QinLing Mountains. With beautiful flowers, attractive smell and rich colors of fruits, it exhibits abundant phenotypic diversity both among and within populations, and has relatively high ornamental value and commercial value. In the recent years, many cherry resources have been lostdue to habitat destruction, replacement of other fruits and extensive management. The latest researches of Chinese cherry mainly have been conducted in partial regions or only on single type (landraces or wilds), which could not comprehensively reveal the current situation of cherry resources of China. In this study,17 SSRs developed from the C. pseudocerasus genome were used to estimate the genetic diversity and population structure of 542 individuals (338 landraces and 204 wild ones) from 60 counties of 11 provinces of China.1. The selection and assessment of SSRs developed from the C. pseudocerasus genome.The selected SSR loci in our study exhibited relatively high polymorphism, specificity, amplification rate and excellent repeatability (An=0.137,I=0.808,PIC=0.367).7 out of 17 loci were evenly distributed across the six out of eight chromosomes of the relative, Cerasus avium.17 SSR loci contained all repeat motifs, mainly including the dinucleotide repeats (64.71%) and trinucleotide repeats (27.27%). Above all, these markers can be effectively used to examine the genetic diversity of C. pseudocerasus.2. The analysis of genetic diversity of Chinese cherryIn this study, we used 17 efficient SSRs to assess the genetic diversity of 338 Chinese cherry landraces and 204 wild cherry individuals according to their types and geographic distributions, respectively. The results showed that the genetic diversity of cherry landraces (Na=5.294, Ne=1.645, Ar=3.940, He=0.332,I=0.641) was lower than the wild ones (Na=5.824,Ne=2.120, Ar=5.240, He=00490,I=0.986). Based on different geographic distributions, the genetic analysis suggested that the two highest levels of genetic diversity were observed in LYG (He=0.355,I=0.672) and LQL (He=0.355,I=0.649), followed by LHBD (He=0.241,I=0.483) and LSC (He=0.241, I=0.483). And that of wild group was as following order as WSC (He=0.491,I=0.986), WQL (He=0.429,I=0.793) and WYG (He=0.411,I=0.764).3. The analysis of population structure and differentiationThe results of STRUCTURE, NJ tree and PCoA indicated that Chinese cherry landraces and wild ones could be roughly divided into two groups and there was frequent gene introgression between them in their overlapping regions. Furthermore, the cherry landraces could be clustered into two subgroups, subgroup Ⅰ (LSC and LYG) and subgroup Ⅱ (LQL and LHBD), showing a clear correlation to geographic distribution. The wilds showed a obvious mixture and crosses, and had no clear structure. Moreover, we detected a relatively high differentiation within LQL and inferred it may be the transition zone between LSC and LHBD.According to the results of AMOVA, the genetic variation mainly occurred within groups. Overall, there was moderate differentiation within Chinese cherry (FST=0.098, Nm=2.298). Moderate differentiation was detected between wild and landraces group (FST=0.095,Nm=2.382). Moreover, the differentiation was relatively high within landraces (FST=0.131, Nm=1.655), yet it was slight within wilds (FST=0.041, Nm=5.771), indicating that the frequent gene flow and numerous shared ancestral polymorphisms might retard the tempo of differentiation within wild group.更多还原