Academy of Scientific and Innovative Research, New Delhi, India.
Mol Biol Rep. 2014 Mar;41(3):1741-52. doi: 10.1007/s11033-014-3023-y. Epub 2014 Jan 16.
Steviol glycoside and gibberellin biosynthetic routes are known as divergent branches of a common origin in Stevia. A UDP-glycosyltransferase encoded by SrUGT74G1 catalyses the conversion of steviolbioside into stevioside in Stevia rebaudiana leaves. In the present study, transgenic Arabidopsis thaliana overexpressing SrUGT74G1 cDNA from Stevia were developed to check the probability of stevioside biosynthesis in them. However, stevioside accumulation was not evident in transgenics. Also, the transgenic Arabidopsis showed no change in GA3 content on SrUGT74G1 overexpression. Surprisingly, significant accumulation of catechin was noticed in transgenics. The transgenics showed a considerable increase in shoot length, root length and rosette area. An increase in free radical scavenging activity of transgenics was noticed. Moreover, the seed yield of transgenics was also increased by 6-15% than control. Additionally, variation in trichome branching pattern on leaf surface of transgenics was observed. The trichome branching pattern was also validated by exogenous catechin exposure (10, 50, 100 ng ml(-1)) to control plants. Hence, present study reports the probable role of SrUGT74G1 from Stevia in catechin accumulation of transgenic Arabidopsis thaliana. Thus, detailed study in present perspective has revealed the role of Stevia SrUGT74G1 gene in trichome branching pattern, improved vegetative growth, scavenging potential and seed yield by catechin accumulation in transgenic Arabidopsis.
甜菊糖甙和赤霉素生物合成途径被认为是甜菊中一个共同起源的分歧分支。一种由 SrUGT74G1 编码的 UDP-糖基转移酶催化甜菊醇甙在甜菊叶中的转化为甜菊糖甙。在本研究中，开发了过表达甜菊 SrUGT74G1 cDNA 的转基因拟南芥，以检查它们中是否有可能合成甜菊糖甙。然而，转基因植物中没有明显的甜菊糖甙积累。此外，转基因拟南芥中 SrUGT74G1 的过表达并没有改变赤霉素 GA3 的含量。令人惊讶的是，在转基因植物中发现了儿茶素的大量积累。转基因植物的茎长、根长和莲座叶面积都有明显增加。转基因植物的自由基清除活性也有所增加。此外，转基因植物的种子产量比对照增加了 6-15%。此外，还观察到转基因植物叶片表面的毛状体分支模式发生了变化。通过向对照植物外源添加儿茶素（10、50、100ng ml(-1))，也验证了毛状体分支模式。因此，本研究报告了甜菊 SrUGT74G1 可能在转基因拟南芥儿茶素积累中的作用。因此，从目前的角度来看，详细的研究揭示了 Stevia SrUGT74G1 基因在毛状体分支模式、增强的营养生长、通过儿茶素积累的清除潜力和种子产量方面的作用。
