Physiological and transcriptomic analyses reveal tea plant (Camellia sinensis L.) adapts to extreme freezing stress during winter by regulating cell wall structure

Abstract

Tea plants grown in high-latitude areas are often damaged by extreme freezing temperatures in winter, leading to huge economic losses. Here, the physiological and gene expression characteristics of two tea cultivars (Xinyang No. 10 (XY10), a freezing-tolerant cultivar and Fudingdabaicha (FDDB), a freezing-sensitive cultivar) during overwintering in northern China were studied to better understand the regulation mechanisms of tea plants in response to natural freezing stress. Samples were collected at a chill (D1), freezing (D2) and recovery (D3) temperature in winter. TEM analysis of integrated leaf ultrastructure at D2 revealed lower malondialdehyde and relative electrical conductivity in XY10 than in FDDB, with serious cell structure damage in the latter, indicating XY10 was more resistant to freezing stress. Differential gene expression analysis among the different samples over winter time highlighted the following gene functions in cell wall metabolism (CesAs, COBLs, XTHs, PGs, PMEs), transcription factors (ERF1B and MYC2), and signal transduction (CDPKs and CMLs). The expression pattern of cellulose and pectin-related genes suggested higher accumulation of cellulosic and pectic materials in the cell wall of XY10, agreeing with the results of cell wall and its components. These results indicated that under the regulation of cell wall genes, the freezing-resistant tea cultivar can better maintain a well-knit cell wall structure with sufficient substances to survive natural freezing damage. This study demonstrated the crucial role of cell wall in tea plant resistance to natural freezing stress and provided important candidate genes for breeding of freezing-resistant tea cultivars.

Transcriptomics of Leaf Development in the Endangered Dioecious Magnolia kwangsiensis: Molecular Basis Underpinning Specialized Metabolism Genes

“…The combination of elevated cell wall investments and a surge in polysaccharide biosynthesis implies that specialized metabolism escalation complements structural enhancement in mature leaves. The mechanistic overlap between defensive chemistry and architectural robustness hints at intriguing complementary selection pressures that shape the duality of structure and function during leaf history [ 25 , 26 , 27 ]. Photosynthetic maturation thus proceeds with tissue resilience and chemical defense amplification to secure plant stability and survival [ 25 , 26 , 28 ].…”

A Review on Rhizosphere Microbiota of Tea Plant (Camellia sinensis L): Recent Insights and Future Perspectives

“…(a) Plant roots secrete secretions in the rhizosphere soil and, by the chelation of aluminum in the soil, form strong complexes and reverse its toxic effect. , (b) After aluminum enters the tea tree, an Al–Si complex (aluminosilicate or hydroxy-aluminosilicate) is formed in the plant to reduce the concentration of soluble aluminum in the body to reduce the internal toxicity of Al 3+ . (c) The last is the distribution of aluminum in the tea plant. − From the point of view of the organ level, after the tea tree roots absorb aluminum, it will be transported to the old roots, old leaves, and old stems of the plant in time. From the cellular level, − the aluminum enriched in the tea plant is mainly concentrated in the cell wall of epidermal cells and parenchyma cells.…”