Evolutionary Landscape of Tea Circular RNAs and Its Contribution to Chilling Tolerance of Tea Plant

Abstract

Chilling stress threatens the yield and distribution pattern of global crops, including the tea plant (Camellia sinensis), one of the most important cash crops around the world. Circular RNA (circRNA) plays roles in regulating plant growth and biotic/abiotic stress responses. Understanding the evolutionary characteristics of circRNA and its feedbacks to chilling stress in the tea plant will help to elucidate the vital roles of circRNAs. In the current report, we systematically identified 2702 high-confidence circRNAs under chilling stress in the tea plant, and interestingly found that the generation of tea plant circRNAs was associated with the length of their flanking introns. Repetitive sequences annotation and DNA methylation analysis revealed that the longer flanking introns of circRNAs present more repetitive sequences and higher methylation levels, which suggested that repeat-elements-mediated DNA methylation might promote the circRNAs biogenesis in the tea plant. We further detected 250 differentially expressed circRNAs under chilling stress, which were functionally enriched in GO terms related to cold/stress responses. Constructing a circRNA-miRNA-mRNA interaction network discovered 139 differentially expressed circRNAs harboring potential miRNA binding sites, which further identified 14 circRNAs that might contribute to tea plant chilling responses. We further characterized a key circRNA, CSS-circFAB1, which was significantly induced under chilling stress. FISH and silencing experiments revealed that CSS-circFAB1 was potentially involved in chilling tolerance of the tea plant. Our study emphasizes the importance of circRNA and its preliminary role against low-temperature stress, providing new insights for tea plant cold tolerance breeding.

miR828a-CsMYB114 Module Negatively Regulates the Biosynthesis of Theobromine in Camellia sinensis

“…27 At the same time, tea is a major cash crop, and its processing, cultivation, and trade hold substantial economic importance. 28 In this study, we identified a theobromine synthase gene, CsTbS (novel-G000134, Figure S1), and a MYB transcription factor, CsMYB114 (CSS0026328, Figure S2), by correlation analysis of extensively targeted metabolomic and transcriptomic data. The regulatory relationship between CsMYB114 and CsTbS was investigated by using a dual-luciferase reporter gene assay, electrophoretic mobility shift, and yeast one-hybridization techniques.…”

“…Its global popularity stems from its health benefits, including antioxidant properties, cardiovascular disease prevention, and potential cancer-fighting ability . At the same time, tea is a major cash crop, and its processing, cultivation, and trade hold substantial economic importance . In this study, we identified a theobromine synthase gene, CsTbS (novel-G000134, Figure S1), and a MYB transcription factor, CsMYB114 (CSS0026328, Figure S2), by correlation analysis of extensively targeted metabolomic and transcriptomic data.…”

Recent progress and perspectives on physiological and molecular mechanisms underlying cold tolerance of tea plants

“…Of them, miR156, miR159, and miR396 showed distinct expression patterns among different cold-sensitive tea varieties under cold conditions ( Zhang et al., 2014b ). In addition, 14 circular RNAs have been identified to contribute to the chilling tolerance of tea plant ( Huang et al., 2023 ).…”

The Construction of lncRNA/circRNA–miRNA–mRNA Networks Reveals Functional Genes Related to Growth Traits in Schima superba

“…Sci. 2024, 25, 2171 2 of 19 stress in Ammopiptanthus nanus [13], the development of embryos via a lncRNA-miRNA-mRNA network in Picea glauca [14], the regulation of floral development in Glycine max via a circRNA-miRNA-mRNA network [15], and the contribution of a circRNA-miRNA-mRNA network to cold tolerance in Camellia sinensis [16]. As the most important genetic and improvement targets, growth traits have long been the focus of forest researchers to produce more forest products and increase economic benefits.…”