水稻和玉米多肽激素基因CEP家族的鉴定及功能分析

发布时间：2018-05-19 19:42

本文选题：水稻 + 玉米　；参考：《中国农业大学》2016年博士论文

【摘要】：植物多肽激素是一类经剪切后形成具有特殊功能的、成熟的多肽,长度一般为20个氨基酸左右,介导植物细胞间信号转导,并广泛参与调控植物生长发育。目前植物中多肽激素家族主要有CLE基因家族、RGF基因家族、ERF基因家族和CEP基因家族等。本论文以粮食作物水稻和玉米为研究对象,在全基因组水平上对CEP多肽激素家族基因进行鉴定,在此基础上,对同源的水稻OsCEP6.1和玉米ZmCEP1基因功能进行了转基因功能分析,以期为进一步探讨CEP多肽激素与作物生长发育的关系提供参考依据。获得的主要研究结果如下：1.在水稻基因组中共鉴定出15个CEP多肽激素基因,定位于水稻的6条染色体上。同源进化分析结果显示,水稻CEP家族基因可以分为2个群,且这两个群的CEP结构域的C-末端都存在相对保守的蛋白序列(SPGV/IGH/N)。利用Rice qTeller数据库对其进行电子表达模式谱分析发现,OsCEP5和OsCEP6.1在水稻的花序分生组织中表达量显著高于其他基因。2.采用实时定量PCR的方法对OsCEP6.1基因的表达模式进行了分析,发现OsCEP6.1具有明显的时空表达特异性,且能够受到外源细胞分裂素诱导上调表达。外源施加人工合成的OsCEP6.1能够显著地抑制初生根和幼苗的生长。另外,我们还获得了OsCEP6.1基因的超表达转基因水稻纯系,对其表型分析结果显示,OsCEP6.1基因水稻超表达株系的株高、分蘖数目、剑叶长度、穗长、一级及二级枝梗数目、粒长、粒宽及千粒重等性状较野生型均显著降低。研究还发现,转基因株系的表型变异是由于细胞变小造成的,而细胞数目并没有发生显著改变。3.在玉米基因组中鉴定出12个CEP多肽激素基因,定位于玉米的8条染色体上。同源进化分析结果显示,玉米CEP家族基因可以分为2个群。利用Maize qTeller数据库对其电子表达模式进行分析发现,在玉米雌穗和雄穗的花序分生组织中,ZmCEPl表达量显著高于其他基因。4.采用实时定量PCR的方法对ZmCEPl的表达模式进行分析,发现ZmCEPl在玉米发育的雌穗和发育的雄穗中表达量较高,能够受到外源细胞分裂素诱导上调表达。原位杂交的结果显示,ZmCEPl主要在玉米雌穗穗轴维管束和未发育完全的小花中表达。获得了ZmCEPl基因的拟南芥和玉米超表达转基因株系,并进行了表型分析,发现超表达ZmCEPl的拟南芥植株表现出初生根变短和植株变小的表型。玉米超表达ZmCEPl株系的株高、穗位高、穗长、穗粗、行粒数、粒长和百粒重也较野生型均显著降低,但是穗行数没有显著差异。
[Abstract]:Plant polypeptide hormone is a kind of mature polypeptide with special function, which is usually about 20 amino acids in length. It mediates plant intercellular signal transduction and is widely involved in regulating plant growth and development. At present, the polypeptide hormone family in plants mainly includes CLE gene family, CEP gene family and so on. In this paper, rice and maize were used as research objects, CEP polypeptide hormone family genes were identified at the whole genome level, and the function of OsCEP6.1 gene and maize ZmCEP1 gene of rice and maize were analyzed. So as to provide reference for further study on the relationship between CEP polypeptide hormones and crop growth and development. The main results obtained are as follows: 1. A total of 15 CEP polypeptide hormone genes were identified in rice genome and located on 6 chromosomes of rice. The results of homologous evolution analysis showed that the rice CEP family genes could be divided into two groups, and the C-terminal of the CEP domain of the two populations had a relatively conserved protein sequence, SPGV / IGH / NV. The expression of OsCEP5 and OsCEP6.1 in inflorescence meristem of rice was significantly higher than that of other genes. The expression pattern of OsCEP6.1 gene was analyzed by real-time quantitative PCR. It was found that OsCEP6.1 had obvious spatiotemporal specificity and could be up-regulated by exogenous cytokinins. Exogenous synthetic OsCEP6.1 could significantly inhibit primary rooting and seedling growth. In addition, we also obtained the pure lines of transgenic rice with OsCEP6.1 gene overexpression. The phenotypic analysis showed that the plant height, the number of tillers, the length of flag leaf, the ear length, the number of primary and secondary branches, and the grain length of OsCEP6.1 transgenic rice lines were obtained. Grain width and 1000-grain weight were significantly lower than those of wild type. The study also found that the phenotypic variation of transgenic lines was caused by the cells becoming smaller, but the number of cells did not change significantly. 3. Twelve CEP polypeptide hormone genes were identified in maize genome and located on 8 chromosomes of maize. The results of homologous evolution analysis showed that maize CEP family genes could be divided into two groups. The expression of ZmCEPl in the inflorescence meristem of female and male ears of maize was significantly higher than that of other genes. The expression pattern of ZmCEPl was analyzed by real-time quantitative PCR. It was found that the expression of ZmCEPl was higher in female ear and male ear of maize, and could be up-regulated by exogenous cytokinin. The results of in situ hybridization showed that ZmCEPl was mainly expressed in the vascular bundles of female spikes and immature florets in maize. Arabidopsis thaliana and maize super-expression transgenic lines with ZmCEPl gene were obtained and phenotypic analysis was carried out. It was found that Arabidopsis thaliana plants with overexpression of ZmCEPl had the phenotypes of shorter initial rooting and smaller plants. The plant height, ear length, ear diameter, grain number per row, grain length and 100-grain weight of ZmCEPl lines were significantly lower than those of wild type, but there was no significant difference in the number of rows per ear.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q943.2

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