PIN-mediated polar auxin transport has been well recognized as being involved in the plant gravity response. Therefore, the genes involved in auxin transport and response, especially the polarly localized PIN-FORMED (PIN) auxin efflux carriers, play crucial roles in plant shoot formation. Shoot curvature is controlled by auxin, and increased auxin levels promote cell elongation at the bottoms of reoriented shoots, resulting in upward bending. Plant shoot architecture formation is regulated by plant hormones, especially auxin gradients, which are integrated into almost all aspects of plant growth and development.

Interestingly, ZIG/SGR4 encodes Qb-SNARE VTI11, which is involved in membrane trafficking between the trans-Golgi network and the vacuole, and the stems of zig/ sgr4 mutants elongate in a zigzag fashion. found that both SGR2 and zigzag ( ZIG) /SGR4 were involved in the formation and function of the vacuole, suggesting that vacuolar integrity participates in shoot gravitropism. It has been established that mutant sgr genes could reduce the plant gravitropism response by regulating endodermal cell development, starch accumulation and amyloplast movement.

In Arabidopsis, shoot responsiveness to gravitropism is regulated by a group of SHOOT GRAVITROPISM (SGR) genes, of which at least nine SGR genes have been isolated and functionally studied. It is thought that sedimentable amyloplasts play a critical role in gravity perception and that endodermal cells containing sedimented amyloplasts function as statocytes in plant shoots. In plants, gravity is sensed by specialized cells called statocytes, and then, a signal is transported to the elongation zone, leading to differential cell growth in the elongation zone to reorient organ growth in response to the gravity signal. However, the molecular mechanism by which shoot architecture formation in woody plants is mediated by gravitropism remains largely unknown. The growth and development of shoots are regulated by diverse factors, including light, temperature and phytohormones, but gravitropism is important for the upward growth of shoots and is a determinant of the form and posture of plants. In higher plants, the morphology of the plant mainly depends on the development and orientation of the shoots therefore, plant shoots, which are usually negatively geotropic, play a crucial role in morphological architecture formation in many plants, such as landscape plants, fruit trees and other plants of economic interest. Metabolomic analysis showed that 13 metabolites overlapped and were significantly changed in the shoots of QQ and LYQQ compared to MZ. Additionally, the DEGs associated with cell expansion, vesicular trafficking, phytohormones, and transcription factors were identified and analysed. 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. Tissue section observation showed that the cell arrangement and shape of zigzag-shaped stems were aberrant compared with those of normal shoots. 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. The Creative Commons Public Domain Dedication waiver ( ) applies to the data made available in this article, unless otherwise stated in a credit line to the data. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material.

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Zigzag plant information