铁离子辐射对拟南芥重力响应机制影响的研究

发布时间：2018-05-05 00:03

本文选题：铁离子辐射 + 拟南芥　；参考：《大连海事大学》2017年硕士论文

【摘要】：空间辐射和微重力是航天飞行中导致生物体损伤与遗传变异的重要风险因素,然而目前对其产生生物学效应的相互作用关系仍然不清楚。本文从表型、细胞以及分子层面,研究铁离子辐射对拟南芥重力响应系统中感受和传递阶段产生的作用机制以及模拟微重力对非同源末端连接通路(Non-homologous end joining,NHEJ)中关键修复蛋白Ku70表达量的影响。将col野生型以及pin2和pgm-1重力不敏感突变体拟南芥的种子分为对照、模拟微重力效应、辐射和复合因素四个实验组。以剂量为0.1 Gy的56Fe离子(LET=107.8keV/μm)辐照处理干种子。辐照后培养7d测定发芽率、计算发芽势;随后,对模拟微重力效应组和复合因素组进行24 h模拟微重力处理,测定所有受试拟南芥根长、根尖偏转角、根尖淀粉体面积,以及野生型拟南芥根尖生长素输出载体蛋白PIN1与损伤修复相关蛋白Ku70的表达量。研究发现,0.1 Gy剂量铁离子辐射不会对野生型以及pin2、pgm-1突变体拟南芥的发芽率造成明显影响,但对其发芽势及幼苗主根长度产生极显著的抑制作用。表现为辐射迫使种子发芽整齐度下降、发芽速度减缓、发芽天数均延长、主根变短。模拟微重力、辐射、复合因素处理均造成野生型拟南芥幼苗根尖偏转角的增大,且复合因素组的根尖偏转角大于模拟微重力效应组;另外,只有野生型幼苗的模拟微重力效应组和复合因素组的根尖淀粉体分布产生了显著增大,辐射组无明显变化。同时发现,铁离子辐射对野生型根尖细胞生长素运输载体PIN1蛋白的表达起抑制作用,而微重力处理呈现相反的作用效果,说明辐射可通过抑制PIN1蛋白表达参与植物向重性的力学信号传导;模拟微重力处理可以显著抑制辐射造成的损伤修复蛋.白Ku70的表达,说明模拟微重力处理对辐射引起的DNA双链断裂损伤修复的NHEJ修复通路有拮抗作用。综上所述,本研究利用野生型和两种重力不敏感突变体(pin2和pgm-1)拟南芥经过一系列实验揭示了空间辐射和微重力对植物产生的协同效应机制,为研究实际空间环境的生物学效应提供了参考。
[Abstract]:Space radiation and microgravity are important risk factors for biological damage and genetic variation in space flight. However, the interaction of biological effects is still unclear. This paper looks at phenotypic, cellular and molecular levels, To study the mechanism of the effect of Fe ~ (2 +) radiation on the receptive and transmission stages of Arabidopsis thaliana gravity response system, and the effect of simulated microgravity on the expression of Ku70, a key repair protein, in non-homologous end joining (NHEJ), a non-homologous terminal junction pathway in Arabidopsis thaliana. The seeds of col wild type and Arabidopsis thaliana with pin2 and pgm-1 gravity insensitive mutants were divided into four experimental groups, simulated microgravity effect, radiation and compound factors. Dry seeds were treated with 0.1 Gy 56Fe ion (107.8 Kev / 渭 m). After 7 days of irradiation, germination rate was measured and germinating potential was calculated. After 24 h simulated microgravity treatment in simulated microgravity effect group and compound factor group, root length, tip deflection angle and starch body area of root tip were measured in all tested Arabidopsis thaliana. And the expression of PIN1 and Ku70 in Arabidopsis thaliana root tip auxin. It was found that Fe ~ (2 +) radiation at 0.1 Gy dose had no significant effect on the germination rate of wild type and Pin2pgm-1 mutant Arabidopsis thaliana, but had a very significant inhibitory effect on germination potential and seedling root length of Arabidopsis thaliana (Arabidopsis thaliana). The results showed that radiation forced the seed germination uniformity to decrease, the germination speed slowed down, the germination days were prolonged, and the main root became shorter. Simulated microgravity, radiation and compound factors all caused the increase of root tip deflection angle of wild-type Arabidopsis thaliana seedlings, and the root tip deflection angle of compound factor group was larger than that of simulated microgravity effect group. The distribution of amyloplast in the root tip of the wild type seedlings was significantly increased in the simulated microgravity effect group and the compound factor group, but there was no obvious change in the radiation group. It was also found that Fe ~ (2 +) radiation inhibited the expression of PIN1 protein of growth hormone transport vector in wild-type root tip cells, whereas microgravity treatment showed the opposite effect. The results showed that radiation could be involved in the mechanical signal transduction of plant orientation by inhibiting the expression of PIN1 protein, and simulated microgravity treatment could significantly inhibit the damage caused by radiation to repair eggs. The expression of white Ku70 suggests that simulated microgravity treatment has an antagonistic effect on the repair pathway of DNA double strand break damage induced by radiation. In conclusion, a series of experiments on Arabidopsis thaliana with wild type and two gravimetric insensitive mutants, PGP 2 and pgm 1, revealed the synergistic effects of space radiation and microgravity on plants. It provides a reference for the study of the biological effects of the actual space environment.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q947

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