水稻类纤维素酶基因CSLF6在磷积累过程中的功能研究

发布时间：2018-04-28 06:17

本文选题：磷积累 + 纤维素　；参考：《华中农业大学》2016年博士论文

【摘要】：磷是植物生长和发育必需的大量元素之一。水稻中虽然有许多磷吸收和转运相关基因被克隆,但是影响水稻磷积累的调控机制尚不清楚。我们克隆了一个禾本科特有的类纤维素基因OsCSLF6,对其功能研究表明OsCSLF6参与水稻磷积累过程。我们获得2个T-DNA突变体oscsl/6-1和oscsl/6-2,突变体均表现为株高变矮,分蘖数减少的表型。RT-PCR结果显示在oscslf6-1和oscslf6-2纯合突变体中均没有检测到OsCSLF6的转录,因此这两个突变体都是OsCSLF6基因缺失的突变体植株。互补实验的结果表明OsCSLF6能够完全互补突变体株高,分蘖数减少的表型。qRT-PCR和GUS染色的结果显示OsCSLF6表现为组成型表达,其中根中表达最高,成熟的叶子中表达最低。在正常供磷条件下,oscslf6突变体表现为磷中毒的表型,且突变体地上部和根部的磷含量都高于野生型。进一步的研究表明突变体中的磷酸盐转运子表达量明显上调。另外,伴随着突变体中磷含量的上调,突变体的主根长度,不定根的长度和数目都显著少于野生型。在低磷条件下,突变体株高变矮、分蘖数和地上部、根的生物重减少的表型都有明显恢复；突变体叶尖枯萎的表型也恢复到野生型状态。这些生理实验表明oscslf6突变体中磷过量积累是导致植株株高和分蘖数减少的原因。扫描电镜结果显示,oscslf6突变体茎秆厚壁组织细胞壁变薄；另外,oscslf6突变体中的纤维素含量明显少于野生型。这些结果显示oscslf6突变体细胞壁有缺陷。我们同时检测了oscslf6突变体的蔗糖含量,测定结果显示oscslf6突变体的蔗糖含量明显高于野生型,突变体蔗糖合成酶基因(OsSUS4/5)和蔗糖转运子(OsSUT1 /OsSUT2/OsSUT4/OsSweetl4)的表达量明显高于野生型。这些结果暗示OsCSLF6基因可能参与碳代谢产物介导的磷积累过程。
[Abstract]:Phosphorus is one of the essential elements in plant growth and development. Although many genes related to phosphorus uptake and transport have been cloned in rice, the regulatory mechanisms affecting phosphorus accumulation in rice are unclear. We cloned a cellulose-like gene OsCSLF6, which is unique to Gramineae, and its function showed that OsCSLF6 was involved in phosphorus accumulation in rice. We obtained two T-DNA mutants, oscsl/6-1 and oscslr / 6-2. The results of RT-PCR showed that OsCSLF6 transcription was not detected in oscslf6-1 and oscslf6-2 homozygous mutants. So both of these mutants are OsCSLF6-deficient mutants. The results of complementary experiment showed that OsCSLF6 could completely complement the phenotypic phenotypes of plant height and reduced tiller number. QRT-PCR and GUS staining showed that OsCSLF6 had the highest expression in the root and the lowest in the mature leaf. Under the condition of normal phosphorus supply, the mutant Oscslf6 showed the phenotype of phosphorus poisoning, and the content of phosphorus in the shoot and root of the mutant was higher than that in the wild type. Further studies showed that the expression of phosphate transporter in mutants was significantly up-regulated. In addition, the length of the main root, the length and the number of adventitious roots of the mutant were significantly lower than that of the wild type. Under the condition of low phosphorus, the plant height of the mutant became shorter, the number of tillers and the aboveground biomass decreased obviously, and the phenotype of leaf tip wilting of the mutant also returned to the wild-type state. These physiological experiments indicated that the excessive accumulation of phosphorus in the oscslf6 mutant was the cause of the decrease of plant height and tiller number. The results of scanning electron microscope showed that the cell wall of the thick wall of stem of Oscoscslf6 mutant became thinner, and the cellulose content of the mutant Oscslf6 was significantly lower than that of the wild type. These results suggest that the cell wall of the oscslf6 mutant is defective. We also detected sucrose content in oscslf6 mutants. The results showed that the sucrose content of oscslf6 mutant was significantly higher than that of wild type. The expression of sucrose synthase gene OsSUS4 / 5 and sucrose transporter OsSUT1 / OsSUT2 / OsSUT4 / OsSweetl4) was significantly higher than that of wild type. These results suggest that OsCSLF6 gene may be involved in the process of phosphorus accumulation mediated by carbon metabolites.
【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q943.2

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