准噶尔无叶豆EsDREB2B基因在烟草中的抗逆功能分析

Analysis on Stress-resistant Functions of EsDREB2B Gene from Eremosparton songoricum in Tobacco

DREB(dehydration responsive element binding protein)转录因子在植物响应非生物胁迫上具有重要作用,是颇具潜力的植物抗逆育种候选基因。本研究旨在通过烟草体系,验证前期从准噶尔无叶豆中克隆的Es DREB2B基因在种子萌发和成苗成长阶段的抗逆功能,并初步探究其调控的下游靶基因。结果表明:转基因株系在干旱、高盐、冷和热胁迫处理下的萌发率都高于野生型烟草,其中盐和热胁迫下萌发率差异尤为显著;两月大转基因烟草与野生型植株进行干旱、高盐、冷和热胁迫处理后,转基因较野生型植株叶片萎蔫,黄化和伤害程度较轻,在热胁迫下差异最为显著;恢复培养后,大多野生型烟草表现为枯死状态,转基因植株则叶片萎蔫减轻并开始生长,并且转基因烟草存活率显著高于野生型,均达到了野生型的3~4倍。ERD10B和Hsp70基因在四种胁迫后的转基因烟草中的表达量均较野生型高,Hsp90在热胁迫下较野生型表达量升高,而Mn SOD,P5CS等基因的表达量变化不显著。以上结果表明,Es DREB2B基因能提高烟草抗干旱、高盐、冷和热胁迫的能力,是具有潜力的抗逆分子育种候选基因。

dehydration-responsive element-binding proteins(DREB) are important regulators in plant responses to abiotic stresses. DREB genes are very promising candidate genes for the research of plant resistance breeding. This study aims at verifying the resistance function of Es DREB2 B, which was identified from the extreme drought-resistant plant Eremosparton songoricum, in the seeds germination and seedings growth stage of model plant tobacco. We would also like to explore whether Es DREB2 B regulates the reported downstream genes of DREB genes. Our results showed that transgenic lines geminated better than the WT plants under drought, high salt, heat and cold stresses, and especially for the high salt and heat stresses. For two-month-old seedlings, after drought, high salt, cold and heat stresses, transgenic plants showed less wilting, etiolation and injuries than WT,especially under heat stress. After returning to normal growth condition, most WT plants were still wilted and some plants even withered, while the transgenic lines turned green and began to grow. As compared to the WT plants,the transgenic plants maintained significant high survival rates after four treatments by increasing 3-4 times. The expression of Es DREB2 B leads to elevated expression of ERD10 B and Hsp70 genes in the transgenic lines under four stresses, however the expression of Hsp90 was enhanced only under heat stress, and other tested genes such as Mn SOD and P5 CS showed less obvious changes after treatments. These findings suggest that Es DREB2 B is responsible for resisting drought, salt, cold and heat stresses, and maybe a helpful resistance gene for molecular breeding.