Gibberellin 2-oxidase 1(CsGA2ox1) involved gibberellin biosynthesis regulates sprouting time in camellia sinensis

Background Tea is an important cash crop and buds are its main product. To elucidate the molecular mechanism of the sprouting time of tea plants, 'Yuchunzao', which was an early sprouting tea cultivar, was studied. 'Echa 1', sprout one week later than 'Yuchunzao' in spring, was used as the control. Results A total of 26 hormonal compounds and its derivatives in tea plants were qualified by using Ultra Performance Liquid Chromatography-Tandem mass spectrometry (UPLC-MS/MS). The result showed that GA(20), GA(3) and ICA were significantly different in 'Yuchunzao' than in 'Echa 1', with GA(20) and GA(3 )up-regulated and ICA down-regulated. Based on the Illumina platform, transcriptome analysis revealed a total of 5,395 differentially expressed genes (DEGs). A diterpenoid biosynthesis related gene, gibberellin 2-oxidase 1 (CsGA2ox1), was downregulated in 'Yuchunzao' compared to 'Echa 1'. CsGA2ox1 regulate the transformation of GA different forms in plants. The relative expression of CsGA2ox1 showed an adverse trend with the content of GA(20) and GA(3). Our results suggest that down regulation of CsGA2ox1 resulted in the accumulation of GA(3) and GA(20), and then promoted sprout of 'Yuchunzao'. Conclusion This study provides theoretical basis of tea plants sprout and guides the tea breeding in practice.