Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, 110021, India.
Transgenic Res. 2012 Oct;21(5):939-57. doi: 10.1007/s11248-011-9577-8. Epub 2011 Dec 9.
Coping with different kinds of biotic and abiotic stresses is the foundation of sustainable agriculture. Although conventional breeding and marker-assisted selection are being employed in mulberry (Morus indica L.) to develop better varieties, nonetheless the longer time periods required for these approaches necessitates the use of precise biotechnological approaches for sustainable agriculture. In an attempt to improve stress tolerance of mulberry, an important plant of the sericulture industry, an encoding late embryogenesis abundant gene from barley (HVA1) was introduced into mulberry plants by Agrobacterium-mediated transformation. Transgenic mulberry with barley Hva1 under a constitutive promoter actin1 was shown to enhance drought and salinity tolerance. Here, we report that overexpression of barley Hva1 also confers cold tolerance in transgenic mulberry. Further, barley Hva1 gene under control of a stress-inducible promoter rd29A can effectively negate growth retardation under non-stress conditions and confer stress tolerance in transgenic mulberry. Transgenic lines display normal morphology to enhanced growth and an increased tolerance against drought, salt and cold conditions as measured by free proline, membrane stability index and PSII activity. Protein accumulation was detected under stress conditions confirming inductive expression of HVA1 in transgenics. Investigations to assess stress tolerance of these plants under field conditions revealed an overall better performance than the non-transgenic plants. Enhanced expression of stress responsive genes such as Mi dnaJ and Mi 2-cysperoxidin suggests that Hva1 can regulate downstream genes associated with providing abiotic stress tolerance. The investigation of transgenic lines presented here demonstrates the acquisition of tolerance against drought, salt and cold stress in plants overexpressing barley Hva1, indicating that Arabidopsis rd29A promoter can function in mulberry.
应对各种生物和非生物胁迫是可持续农业的基础。尽管传统的育种和标记辅助选择正被用于桑树（Morus indica L.）以培育更好的品种，但这些方法所需的较长时间周期需要使用精确的生物技术方法来实现可持续农业。为了提高桑树（桑树是养蚕业的重要植物）的抗逆性，我们通过农杆菌介导的转化将大麦（HVA1）的一个编码晚期胚胎丰富基因导入桑树。结果表明，在组成型启动子 actin1 下表达大麦 Hva1 的转基因桑树增强了耐旱性和耐盐性。在这里，我们报告大麦 Hva1 的过表达也赋予了转基因桑树的耐寒性。此外，在胁迫诱导启动子 rd29A 控制下的大麦 Hva1 基因可以在非胁迫条件下有效消除生长迟缓，并赋予转基因桑树的抗逆性。转基因株系表现出正常的形态，增强了生长，并在耐旱、耐盐和耐寒条件下具有更高的耐受性，这可以通过游离脯氨酸、膜稳定性指数和 PSII 活性来衡量。在胁迫条件下检测到蛋白质积累，证实了 HVA1 在转基因植物中的诱导表达。对这些植物在田间条件下的抗逆性评估表明，它们的整体表现优于非转基因植物。应激响应基因如 Mi dnaJ 和 Mi 2-cysperoxidin 的增强表达表明，Hva1 可以调节与提供非生物胁迫耐受性相关的下游基因。本文对转基因株系的研究表明，过表达大麦 Hva1 的植物获得了对干旱、盐和冷胁迫的耐受性，表明拟南芥 rd29A 启动子可以在桑树中发挥作用。
