Transcriptome and metabolite analyses provide insights into zigzag-stem formation in tea plants (Camellia sinensis)

Abstract BackgroundShoot orientation is important for plant architecture formation, and the zigzag shoot is a special trait of many plants. The zigzag-shaped shoot has been selected and well studied in Arabidopsis, however, the regulatory mechanism of zigzag-shaped shoot development in other plants especially woody plants is largely unknown.ResultsIn this study, tea plants with zigzag shoots, namely, Qiqu (QQ) and Lianyuanqiqu (LYQQ), were investigated and compared with the erect-shoot tea plant Meizhan (MZ) in an attempt to reveal the regulation of zigzag-shoot formation. Tissue section observation showed that the cell arrangement and shape of zigzag stems were aberrant compared with those of normal shoots. Moreover, a total of 2175 DEGs were identified from the zigzag shoots of the tea plants QQ and LYQQ compared to the shoots of MZ using transcriptome sequencing, and the DEGs involved in the “Plant-pathogen interaction”, “Phenylpropanoid biosynthesis”, “Flavonoid biosynthesis” and “Linoleic acid metabolism” pathways were significantly enriched. Additionally, the DEGs associated with cell expansion, vesicular trafficking, phytohormones, and transcription factors were identified and analysed. Metabolomic analysis showed that 13 metabolites overlapped and were significantly changed in the shoots of QQ and LYQQ compared to MZ.ConclusionsOur results suggest that zigzag-shaped shoot formation might be associated with the gravitropism response and polar auxin transport in tea plants and provides a valuable foundation for further understanding the regulation of plant architecture formation and for the cultivation and application of horticultural plants in the future.