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中国北方主流海带品种遗传多样性分析以及种海带孢子囊成熟和温度的关系研究
李霞
学位类型硕士
导师逄少军
2015-05-15
学位授予单位中国科学院大学
学位授予地点北京
学位专业海洋生物学
关键词海带 Ssr 遗传多样性 温度 孢子囊
摘要 作为我国重要的经济藻类,海带品系的选择以及新品系的培育直接关系到人们的切身利益。然而当前,市场上的海带商品名称使用混乱,各个海带品系之间的遗传关系并不明确,人们仅仅通过其表型特征进行品系的鉴定,无法保证海带种质资源的合理保存与利用,直接制约了海带产业的发展。因此,通过微卫星分子标记的研究方法,研究了来自我国北方山东省7家育苗场的15个代表性养殖海带品系的遗传多样性,以期澄清各个海带品系之间的遗传关系,同时为海带种质的保存提供一定理论依据。通过15对SSR引物,共检测出94个等位基因,特异等位基因25个,每对引物检测的等位基因数为3~17不等。15个海带品系的Nei’s基因多样性(H)和香农多样性指数(I)分别为0.466和0.862,表明品系水平上,海带具有中高等的遗传多样性。其中,海带品系C12的多态性最高(H:0.488;I:0.888),而品系202的多态性最低(H:0.305;I:0.506)。15个海带品系间的遗传距离在0.007~0.547之间,遗传相似系数在0.579~0.993之间。根据品系之间的遗传距离,通过UPGMA法构建的系统树图将15个海带养殖品系分成3大类:品系C033独自构成一个分枝;品系205和202构成一个分枝;其它12个品系聚类在一起。同时,来自同一个育苗场的海带品系倾向于聚类在一起,如品系 C08,C09和C11。AMOVA 分析显示,11.39%的遗传变异存在于不同的品系间,88.61%存在于品系内部。遗传分化系数(Gst)的值为0.128,基因流(Nm)为1.702,表明海带品系之间具有中等水平的遗传差异和一定程度的基因交流。通过对12个海带品系(202,205和C033除外)进行AMOVA分析,显示品系内的遗传变异(95.97%)远远大于品系间的遗传变异(4.03%)。同时,Gst为0.059,Nm为3.970,表明这12个海带品系间遗传分化程度较低,具有较强的基因交流。这些数据表明,15个养殖海带品系都具备较高的基因多样性,从而更好地适应复杂多变的环境。然而,这些品系之间的遗传距离和遗传变异并不高,暗示着某些养殖海带品系间可能出现了混杂。本实验发现了一些特异的SSR分子,可能对未来海带品系的鉴定,提供一定的理论支持。在我国北方海区,人工栽培的海带在成熟后期被用作采孢子育苗的种菜,为了能够节约制冷成本,合理延长种海带在海上的预留时间,系统研究了不同温度(20℃、21℃、22℃、23℃、24℃)和培养时间(4天、8天、12天、16天)对两个海带品系(“205”和“C033”)孢子放散能力及胚孢子萌发率、受精率、雌配子体发育和幼孢子体生长的影响。结果表明:当海水温度达到24℃时,孢子囊几乎丧失了放散能力,20~23℃的游孢子放散量差别不显著。在相同温度下,孢子囊培养时间为12天和16天的胚孢子萌发率大于4天和8天;同时,孢子囊培养16天的雌配子体和幼孢子体具有最小值。在相同培养时间下,23℃(或24℃)的雌配子体和幼孢子体远远小于20~22℃。相关性分析表明,海带雌配子体大小与幼孢子体大小具有显著正相关性(P<0.01)。整体而言,当温度达到23℃或培养时间达到16天时,海带孢子囊受到了胁迫,不利于雌配子体的发育和幼孢子体的生长。温度对孢子囊的作用更迅速,而时间对孢子囊的作用较为缓慢,可能是一种累积效应。
其他摘要As one of the most important economic marine macroalgae, Saccharina japonica plays a vital role in the national economy and people’s lives. Cultivar selection and breeding are very important for the cultivation of S. japonica; however, the genetic relationships among various cultivars are unclear and the commerical names in market are always confusing. People often distinguish one cultivar from another by their morphological characteristics and economic traits, such as colour, length and so on, which makes it hard to guarantee the preservation and utility of germplasm resources. Therefore, SSR technique was applied to study the genetic diversity and relationships of 15 main cultivars (20 individuals per cultivar) of S. japonica obtained from 7 nurseries in Shandong Province. 15 out of 88 SSR primers were selected in the experiment. A total of 94 alleles were generated across all samples, among which 25 are unique, with allele numbers ranged from 3 to 17 per primer. All of the 15 cultivars exhibited relatively high standard of genetic diversity, as revealed by the average of the Nei’s genetic diversity (H) and the Shannon's Information index (I) being 0.466 and 0.862, respectively. At the cultivar level, C12 showed the highest genetic diversity (H:0.488;I:0.888) and 202 showed the lowest (H:0.305;I:0.506). Genetic distance among 15 cultivars ranged from 0.007 to 0.547, and genetic identity ranged from 0.579 to 0.993. Based on genetic distance among cultivars, the phylogenetic tree was constructed by using UPGMA method. It was clearly suggested from the dendrogram that all cultivars could be divided into three groups: cultivar C033 was clustered into the first group, cultivar 205 and 202 were closer to each other and clustered as the second group, the last one was constituted by other 12 cultivars. Analysis of molecular variance (AMOVA) revealed that 11.39% of variation resided among cultivars, while 88.61% within cultivars. The total Gst value was 0.128 and the gene flow (Nm) was 1.702, indicating a intermediate genetic differentiation and a certain amount of gene flow among all 15 cultivars. When applying AMOVA to 12 cultivars except 202, 205 and C033, the variance among cultivars (95.97%) was especially higher than it within cultivars (4.03%), with total Gst value was 0.059 and the gene flow (Nm) was 3.970, implying low genetic differentiation and relatively high gene flow among these 12 cultivars. All the results showed that the 15 cultivars of S. japonica had a relatively high genetic diversity level which was beneficial to adapt to the changeable environment, however, some of the cultivars might be mixed with each other, as indicated by their genetic distance and genetic variation. Fortunately, some effective SSR markers had been found in this experiment, which may be helpful in strain identification.

In the northern part of China, parental sporophytes of the farmed seaweed S. japonica that are used for releasing spores are selected from the farmed population. The recirculated-cold water system is applied to produce seedlings of S. japonica (artificially cooled from 24℃ to ca. 7℃). The less the days to culture the seedlings, the lower the production cost. Since the parental plants are maintained on longlines in the sea, elongation of maintenance of them in the water will have to face up to the rising temperature in the summer (from 20 to 25℃). For S. japonica, there has been no study to elucidate the effect of the rising temperature on the ability of sorus to release spores and the performance of gametogenesis as well as the growth of the resulted sporophytes. In the present study, we used two strains “205” and “C033” as the subjects, arranged five temperatures and four culture periods in combination to study the impact. The results indicate that, (1) spore release failed at 24℃, but showed no apparent difference from 20 to 23℃; (2) germination rates of spores from sorus cultured on day 12 and 16 under the same temperature were higher than that of day 4 and 8; (3) female gametophytes and the resulted sporophytes from sorus cultured at 23℃ were much smaller than that from 20-22℃ at the same culture time; (4) under identical conditions, both female gametophytes and the resulted sporophytes were the smallest on day 16 in all culture trials; (5) size of gametophytes were positively co-related with the size of sporophytes. In summary, sorus of the parental plants are apparently in stressed conditions when in temperature higher than 23℃ or incubated for more than 16 days at temperature from 20-23℃. 
学科领域主要研究方向 ; 海洋生物学
语种中文
文献类型学位论文
条目标识符http://ir.qdio.ac.cn/handle/337002/23254
专题实验海洋生物学重点实验室
作者单位中国科学院海洋研究所
第一作者单位中国科学院海洋研究所
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李霞. 中国北方主流海带品种遗传多样性分析以及种海带孢子囊成熟和温度的关系研究[D]. 北京. 中国科学院大学,2015.
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