Background: Shoot orientation is important for plant architecture formation, and zigzag-shaped shoots are a special trait found in many plants. Zigzag-shaped shoots have been selected and thoroughly studied in Arabidopsis; however, the regulatory mechanism underlying zigzag-shaped shoot development in other plants, especially woody plants, is largely unknown.
Results: In this study, tea plants with zigzag-shaped 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-shaped shoot formation. Tissue section observation showed that the cell arrangement and shape of zigzag-shaped stems were aberrant compared with those of normal shoots. Moreover, a total of 2175 differentially expressed genes (DEGs) were identified from the zigzag-shaped 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.
Conclusions: Our results suggest that zigzag-shaped shoot formation might be associated with the gravitropism response and polar auxin transport in tea plants. This study 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.
Keywords: Auxin transport; Gravitropism response; Stem development; Tea plant; Zigzag-shaped stem.
Conflict of interest statement
The authors declare that they have no competing interests.
Comparative transcriptome study of hairy and hairless tea plant (Camellia sinensis) shoots.J Plant Physiol. 2018 Oct;229:41-52. doi: 10.1016/j.jplph.2018.07.002. Epub 2018 Jul 17. J Plant Physiol. 2018. PMID: 30032044
Global transcriptome and gene regulation network for secondary metabolite biosynthesis of tea plant (Camellia sinensis).BMC Genomics. 2015 Jul 29;16(1):560. doi: 10.1186/s12864-015-1773-0. BMC Genomics. 2015. PMID: 26220550 Free PMC article.
Biochemical and transcriptome analyses of a novel chlorophyll-deficient chlorina tea plant cultivar.BMC Plant Biol. 2014 Dec 10;14:352. doi: 10.1186/s12870-014-0352-x. BMC Plant Biol. 2014. PMID: 25491435 Free PMC article.
Differential transcriptome analysis of leaves of tea plant (Camellia sinensis) provides comprehensive insights into the defense responses to Ectropis oblique attack using RNA-Seq.Funct Integr Genomics. 2016 Jul;16(4):383-98. doi: 10.1007/s10142-016-0491-2. Epub 2016 Apr 20. Funct Integr Genomics. 2016. PMID: 27098524
Role of endodermal cell vacuoles in shoot gravitropism.J Plant Growth Regul. 2002 Jun;21(2):113-9. doi: 10.1007/s003440010047. Epub 2002 May 24. J Plant Growth Regul. 2002. PMID: 12024223 Review.