College of Horticulture, Fujian Agriculture and Forestry University/Key Laboratory of Tea Science in Universities of Fujian Province, Fuzhou, 350002, China.
College of Tea and Food Science, Wuyi University, Wuyishan, 354300, China.
BMC Plant Biol. 2020 Mar 4;20(1):98. doi: 10.1186/s12870-020-2311-z.
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.
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.
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.
shoot orientation 是植物形态建成的重要因素，而 zigzag-shaped shoots 是许多植物中特有的一种特征。 zigzag-shaped shoots 在拟南芥中已经被选择和深入研究；然而，其他植物，特别是木本植物 zigzag-shaped shoot 发育的调控机制在很大程度上是未知的。
本研究调查了具有 zigzag-shaped shoots 的茶树品种，即 Qiqu（QQ）和 Lianyuanqiqu（LYQQ），并与直立 shoot 茶树品种 Meizhan（MZ）进行了比较，试图揭示 zigzag-shaped shoot 形成的调控机制。组织切片观察表明， zigzag-shaped 茎的细胞排列和形状与正常 shoot 的不同。此外，通过转录组测序，从茶树的 zigzag-shaped shoots 中总共鉴定出 2175 个差异表达基因（DEGs），与 MZ 的 shoots 相比，其中涉及“植物-病原体相互作用”、“苯丙烷生物合成”、“类黄酮生物合成”和“亚油酸代谢”途径的 DEGs 显著富集。此外，还鉴定和分析了与细胞扩张、囊泡运输、植物激素和转录因子相关的 DEGs。代谢组学分析表明，在 QQ 和 LYQQ 的 shoots 中，有 13 种代谢物重叠且显著变化，与 MZ 相比。
我们的结果表明， zigzag-shaped shoot 的形成可能与茶树的向重力性反应和极性生长素运输有关。本研究为进一步了解植物形态建成的调控机制以及未来园艺植物的培育和应用提供了有价值的基础。
