缺镁诱导拟南芥根毛发育中乙烯、一氧化氮和生长素作用的研究

发布时间：2018-02-24 12:33

本文关键词： 缺Mg 乙烯一氧化氮生长素根毛　出处：《浙江大学》2017年博士论文　论文类型：学位论文

【摘要】：镁是植物生长发育必需的营养元素之一,参与植物许多生理生化过程。然而,由于镁离子在酸性和砂质土壤中容易淋失以及与其它阳离子的拮抗作用,极易造成作物缺镁,从而影响作物的产量和品质。掌握植物的耐缺镁机制对于利用生物技术或遗传育种手段培育耐缺镁作物新品种具有重要的科学意义。本论文以模式植物拟南芥及一氧化氮(NO)、乙烯和生长素相关的突变体为材料,并结合药理学处理手段,研究了乙烯、NO和生长素调控缺镁诱导根毛发育的作用机制。主要研究结果如下:缺镁能够明显提高野生型拟南芥根系中根毛起始和伸长,同时能够通过增加ACC合成酶(ACS)和ACC氧化酶(ACO)、NR和NOS-L的活性,生长素转运体AUX1,PIN1,和PIN2基因及蛋白的表达分别提高乙烯、NO和生长素在根系中的积累。在正常供镁条件下,乙烯前体ACC或NO供体SNP或人工合成生长素NAA处理均能提高所有被测根段根毛的发育;而在缺镁条件下,乙烯抑制剂STS或NO内源清除剂c-PTIO或生长素运输抑制剂NPA的施用均能够明显抑制缺镁诱导的根毛起始和伸长。另外,与野生型拟南芥所不同的是,缺镁诱导的根毛起始和伸长在乙烯不敏感突变体ein2-5和ein3-1,NO缺陷突变体nia1,2和noal,生长素运输缺陷突变体aux1-7,pin1-和pin2中均显著受阻。这些结果表明乙烯、NO和生长素均参与了缺镁诱导的根毛发育。基于上述结果,我们进一步研究了乙烯、NO和生长素在调控缺镁诱导的根毛发育中的相互关系。在缺镁的条件下,乙烯、NO和生长素各自之间均能通过提高根系中的ACS、ACO活性,或NR和NOS-L活性,或AUX1,PIN1和PIN2转运体的表达,相互促进它们在根系中的积累。这说明在缺镁的根系中,乙烯、NO和生长素在它们的含量提升中形成了正向的循环调控机制。我们继而研究了这种调控机制是否在缺镁诱导根毛发育中起作用。结果表明,在缺镁的条件下,乙烯能部分逆转c-PTIO对Col-0根毛起始和伸长的抑制作用,同时也显著促进了 nia1,2和noa1突变体中的根毛起始和伸长;反之,NO也能部分逆转STS对缺镁Col-0根毛起始和伸长的抑制作用,并也促进了ein2-5 ein3-1和突变体中的根毛起始和伸长。这表明,乙烯和NO交互式地调控了缺镁诱导的根毛发育。然而,在缺镁的条件下,虽然NAA能逆转c-PTIO或STS对Col-0根毛起始和伸长的抑制作用,也能促进ein2-5,etr3-1,nia1,2和noa1突变体中的根毛起始和伸长;但是,同样在缺镁条件下,ACC和SNP却并不影响NPA对Col-0根毛起始和伸长的抑制作用,也不能提升aux1-7,pin1-1和pin2突变体的根毛起始和伸长。这说明生长素作为乙烯和NO的下游信号分子调控了缺镁诱导的根毛发育。
[Abstract]:Magnesium is one of the essential nutrient elements in plant growth and development, which is involved in many physiological and biochemical processes in plants. However, magnesium ions are easy to be leached in acidic and sandy soils and antagonistic to other cations, which can easily lead to magnesium deficiency in crops. Therefore, it is of great scientific significance to master the mechanism of magnesium tolerance in plants for the cultivation of new varieties of magnesium deficient crops by means of biotechnology or genetic breeding. In this paper, Arabidopsis thaliana and Arabidopsis thaliana are used as model plants. Nitric oxide (no), ethylene and auxin related mutants were used as materials, Combined with pharmacological treatment, the mechanism of no and auxin regulating root hair development induced by magnesium deficiency was studied. The main results were as follows: magnesium deficiency could significantly increase root hair initiation and elongation in wild type Arabidopsis thaliana root system. At the same time, the expression of auxin transporter AUX1PIN1 and PIN2 gene and protein increased the accumulation of no and auxin in roots by increasing the activities of ACC synthase (ACSS) and ACC oxidase (ACOC) and NOS-L, respectively. Under the condition of normal magnesium supply, the expression of auxin transporter AUX1 and PIN2 gene and protein increased the accumulation of no and auxin in roots, respectively. The treatment of ethylene precursor ACC or no donor SNP or synthetic auxin NAA could improve the development of root hair in all tested root segments, but under magnesium deficiency, The application of ethylene inhibitor STS or no endogenous scavenger c-PTIO or auxin transport inhibitor NPA significantly inhibited root hair initiation and elongation induced by magnesium deficiency. The root hair initiation and elongation induced by magnesium deficiency were significantly blocked in ethylene insensitive mutants ein2-5 and ein3-1 no deficiency mutants nia1t2 and noalal2, aux1-7mpin1- and pin2. These results indicate that ethylene nitrite and auxin are both involved in the deficiency. Magnesium induced root hair development. Based on the above results, We further studied the relationship between no and auxin in regulating the root hair development induced by magnesium deficiency. Under the condition of magnesium deficiency, the activities of ACSN, NR and NOS-L in roots could be increased by increasing the activities of ACSO, NR and NOS-L in roots. Or the expression of AUX1PIN1 and PIN2 transporter, which promotes their accumulation in root system. The effects of magnesium deficiency on root hair development were studied. The results showed that under the condition of magnesium deficiency, no and auxin formed a positive cyclic regulation mechanism, and the results showed that, under the condition of magnesium deficiency, no and auxin might play an important role in root hair development induced by magnesium deficiency, and the results showed that under the condition of magnesium deficiency, Ethylene partially reversed the inhibition of c-PTIO on root hair initiation and elongation in Col-0, and promoted root hair initiation and elongation in nia1t2 and noa1 mutants, whereas no also partially reversed the inhibition of STS on root hair initiation and elongation of Mg-deficient Col-0. It also promoted the initiation and elongation of root hair in ein2-5 ein3-1 and mutant. This indicated that ethylene and no interactively regulated root hair development induced by magnesium deficiency. Although NAA can reverse the inhibition of c-PTIO or STS on the initiation and elongation of Col-0 root hair, it can also promote the initiation and elongation of root hair in ein2-5tr 3-1nnia1t2 and noa1 mutants. Under the condition of magnesium deficiency, NPA and SNP did not affect the inhibition of NPA on the initiation and elongation of Col-0 root hair. The root hair initiation and elongation of aux1-7 pin1-1 and pin2 mutants could not be increased, which indicated that auxin, as a downstream signal molecule of ethylene and no, regulated root hair development induced by magnesium deficiency.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q945

【相似文献】