转BnTR1基因的烟草对多种逆境胁迫的抗性研究

The analysis of BnTR1 enhances a variety of resistance in Nicotiana benthamiana

摘要:

全球气候变化导致植物频繁遭遇干旱和盐胁迫，研究植物抗旱耐盐并培育抗旱耐盐植物新材料已经成为植物研究领域的热点问题.来源于油菜的BnTR1是一个定位于膜上的E3连接酶，该基因表现出热的诱导性并赋予植物耐热特定性.为了研究BnTR1的其他抗逆能力，本实验将该基因转化到了本生烟中，并研究了转基因烟草对干旱和盐胁迫下的生长发育变化，发现与非转基因对照相比，转基因烟草对甘露醇和PEG模拟干旱表现出较强的抗性，尤其是PEG胁迫时，三个转基因株系在生物量的积累和整体长势方面都优于对照.干旱处理20d后复水并培养14d后，对照烟草全部枯死，但是所有转基因烟草都恢复生长直至开花结果.这些结果都说明BnTR1赋予转基因烟草对干旱的抗旱特性.当把烟草叶片圆片浸泡在系列盐水中，盐浓度超过600mM时，对照烟草圆片受损白化，而转基因烟草圆片能保持较大面积的绿色，说明在盐胁迫时转基因烟草更能保持叶绿体和叶绿素的稳定，也说明转基因烟草对盐胁迫的抗性的增强.在热激处理后，热激蛋白基因HSP90和HSP70在所有烟草中的表达量都提高了，增加的量在对照和转基因株系中并无差异，而正常条件下不表达的HSF30 和sHSP17.6 都表达了，HSF30增加了50%，sHSP17.6增加了30%.这些结果说明了转BnTR1基因增强了转基因烟草对多种逆境胁迫的抗性，为进一步研究BnTR1基因的功能奠定了基础，也为其应用提供了实验证据.

Abstract:

Abstract: Owing to the global climate change, frequent drought and salt stress have happened to most plants. As a result, it has become a hot issue in agricultural field to research in tolerance mechanisms of plants and to cultivate new plant materials that can tolerate salt and drought. Derived from rape, BnTR1 is an E3 ligase located in the membrane, and its expression can be induced by heat stress,and then gives the heat resistance to plants. BnTR1 was transformed into Nicotiana benthamiana to study the growth of transgenic Nicotiana benthamiana under drought and salt stress.What’s more, compared with the control, this transgenic plant shows a better resistance to mannitol and PEG, especially in growth status and accumulation of biomass under PEG stress. After 20 days under drought treatment, plants were rewatered and then cultivated for 2 weeks, and all transgenic Nicotiana benthamiana were recovered from wilting, and all wild type Nicotiana benthamiana died. These results indicated that Nicotiana benthamiana can be resistant to drought with BnTR1. When leaves were treated with hydrosaline solution, transgenic Nicotiana benthamiana could maintain green even as salt concentration was above 600mM, while control plants became albino. This result suggested that chloroplast and chlorophyll in transgenic Nicotiana benthamiana can be more stable under salt stress, and transgenic Nicotiana benthamiana can be more resistant to salt stress. After heat shock, the expression of HSP90 and HSP70 in transgenic Nicotiana benthamiana and controls were all up-regulated, and there were no significant difference in increment between transgenic plants and controls. The expression of HSF30 and sHSP17.6 were also induced which can’t be detected in normal condition, HSF30 increasing 50% and sHSP17.6 increasing 30%. These researches illustrated that Nicotiana benthamiana can survive in many stressful conditions when transformed with BnTR1. This experiment laid a good foundation for the study of BnTR1, and also provided an experimental proof for its application.