DoDELLA1, a DELLA protein from Dioscorea opposite, regulates the growth and development in transgenic tobacco by controlling gibberellin level

Gibberellins (GAs) are involved in many aspects of plant growth and development. DELLA proteins are major repressors of GA signaling as a transcription factor to regulate plant growth. Yam (Dioscorea opposite) tuber development is regulated by GA. In a previous study, we have identified and characterized a gene encoding DELLA protein and named as DoDELLA1 from yam tuber. However, its function is unclear. The results showed that DoDELLA1 expression patterns of leaf, stem and tuber in two yam cultivars, Guihuai 16 (GH16) and Guihuai 5 (GH5), were in response to GA(3). DELLA and VHYNP domain of DoDELLA1 protein had transcriptional capacity, LH, VHIID and SAW domain were not involved in transcriptional activity by transcriptional activation analysis. Compared to wild-type plants, over-expression of DoDELLA1 in tobacco resulted in dwarf and late-flowering or no flowering plants. The contents of GA(1) and GA(3) exhibited a decreasing trend in transgenic tobacco, and the expression levels of GA metabolism-related genes displayed a decreasing trend. Moreover, GA(3) treatment rescued the phenotype of DoDELLA1 transgenic tobacco plants, and DoDELLA1 transgenic tobacco plants had feedback and feed-forward mechanism of GA control, whereby bioactive GA reduced GA synthesis genes expression level and increased GA deactivation genes expression level. Our results suggest that DoDELLA1 is involved in the regulation of transgenic tobacco plant growth and development by regulating GA(3) level via the regulation of the expression of GA metabolism-related genes.

Automated summary

This study reveals the important role of DoDELLA1 in regulating yam tuber development and transgenic tobacco growth by modulating the expression of GA metabolism-related genes.