Transgenic Tobacco Overexpressing Tea cDNA Encoding Dihydroflavonol 4-Reductase and Anthocyanidin Reductase Induces Early Flowering and Provides Biotic Stress Tolerance

Abstract

Flavan-3-ols contribute significantly to flavonoid content of tea (Camellia sinensis L.). Dihydroflavonol 4-reductase (DFR) and anthocyanidin reductase (ANR) are known to be key regulatory enzymes of flavan-3-ols biosynthesis. In this study, we have generated the transgenic tobacco overexpressing individually tea cDNA CsDFR and CsANR encoding for DFR and ANR to evaluate their influence on developmental and protective abilities of plant against biotic stress. The transgenic lines of CsDFR and CsANR produced early flowering and better seed yield. Both types of transgenic tobacco showed higher content of flavonoids than control. Flavan-3-ols such as catechin, epicatechin and epicatechingallate were found to be increased in transgenic lines. The free radical scavenging activity of CsDFR and CsANR transgenic lines was improved. Oxidative stress was observed to induce lesser cell death in transgenic lines compared to control tobacco plants. Transgenic tobacco overexpressing CsDFR and CsANR also showed resistance against infestation by a tobacco leaf cutworm Spodoptera litura. Results suggested that the overexpression of CsDFR and CsANR cDNA in tobacco has improved flavonoids content and antioxidant potential. These attributes in transgenic tobacco have ultimately improved their growth and development, and biotic stress tolerance.

Overexpression of CsDFR and CsANR enhanced flavonoids accumulation and antioxidant potential of roots in tobacco

“…Thus, the decreased anthocyanins and increased flavan-3-ols/proanthocyanidins indicate the diversion of carbon flux towards flavan-3-ols/proanthocyanidin biosynthesis in roots of CsDFR and CsANR overexpressing tobacco. Similar diversion has earlier been reported in plant shoots (Han et al 2012;Kumar et al 2013b). Also, the ectopic expression of apple MdANR gene has been reported for higher proanthocyanidins and lower anthocyanins in tobacco flower (Han et al 2012).…”

“…The DFR and ANR enzymes have also been characterized from a number of other plant species (Shimada et al 2005;Shen et al 2006;Piero et al 2006;Paolocci et al 2007). Transgenic plants raised with some of these genes were analyzed primarily for change in flavonoids content in leaf or shoot part (Xie et al 2004;Takahashi et al 2006;Xie et al 2006;Kovinich et al 2011Han et al 2012Kumar and Yadav 2013;Kumar et al 2013b). However, influence of overexpression of such genes encoding DFR and ANR enzymes on flavonoids accumulation and antioxidant potential in plant roots as well as their role in root growth under normal conditions and tolerance against Al toxicity is lacking.…”

Genetic Diversity and Association Mapping for Agromorphological and Grain Quality Traits of a Structured Collection of Durum Wheat Landraces Including subsp. durum, turgidum and diccocon

“…This MTA was also reported in a tetraploid wheat collection evaluated under one environment [8]. According to the genomic sequence of this marker, the putative corresponding gene function was anthocyanidin reductase, a type of protein which induces early flowering and improves seed yield in transgenic tobacco [66]. The importance of this MTA was supported by its presence in subsp.…”

The large-scale investigation of gene expression in Leymus chinensis stigmas provides a valuable resource for understanding the mechanisms of poaceae self-incompatibility

“…DFR are key regulatory enzymes of flavonoid biosynthesis [86]. Flavonoids are ubiquitous plant secondary metabolites and are accumulated in different organs and tissues of plants [87].…”