Cold Stress-induced Glucosyltransferase CsUGT78A15 is Involved in the Formation of Eugenol Glucoside in Camellia sinensis

Tea [Camellia sinensis (L.)] plants are important economic crop in China. Chilling stress and freezing damages have seriously affected the quality of tea products that have been already regarded as the main restricting factors to industry’s development. Nitric oxide (NO) plays a crucial role in resistance of abiotic stresses. An experiment was conducted in an artificial climate chamber to study the effect of NO on tea plants grown under chilling stress (–2 °C) for 0, 6, 24, 48, and 72 h. Foliar application of sodium nitroprusside (SNP) at a rate of 500 μmol·L−1 was used as NO donor. The experiment contained two factors: the first was the foliar application with SNP or distilled water, and the scond one was the chilling (–2 °C) exposure time (0, 6, 24, 48, and 72 h). The effects of NO on membrane lipid peroxidation, osmotic adjustment substances, and antioxidant activity under cold stress were studied. In addition, the gene expression of CsICE1 and CsCBF1 in respond to NO addition were also investigated using real-time polymerase chain reaction (RT-PCR). The results show that foliar addition of NO (500 μmol·L−1 of SNP) reduce the relative conductivity of tea leaves, inhibits the elevated malondialdehyde content, promotes the accumulation of proline, soluble protein and sugar, and increases the superoxide dismutase, catalase activities, thereby alleviates the damage of cold stress on tea leaves. The CsICE1 expression in 500 μM SNP treatment was peaked at 24 h of low temperature stress, while it did not express at normal temperature. Therefore, the current study is considered a good scientific material in understanding how tea plants sense and defense the chilling stress and that plays an important role to improve the level of production and economic benefits. It is also provided significant theory bas to control chilling stress in tea plants.

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Transcriptomic Analysis of Camellia Sinensis (L.) Kuntze Var. Niaowangensis Q. H. Chen Leaves Under Cold Stress

10.21203/rs.3.rs-1172962/v1 ◽

2021 ◽

Author(s):

Ying Wang ◽

Cheng Wan ◽

Leijia Li ◽

Zhun Xiang ◽

Jihong Wang ◽

...

Keyword(s):

Cold Stress ◽

Candidate Genes ◽

Cold Tolerance ◽

Camellia Sinensis ◽

Resistance Breeding ◽

Guizhou Province ◽

Cdna Libraries ◽

Control Group ◽

P Value ◽

Illumina Hiseq

Abstract Fine varieties of the Yunwu Tribute Tea (Camellia Sinensis (L.) Kuntze var. niaowangensis Q. H. Chen) are distributed on the Yunwu Mountain, Guiding County, Guizhou province, China. Cold stress usually occurs in winter and is one of the most significant environmental factors restricting the growth of this plant as well as its geographical distribution. However, only few systematic studies have examined the molecular mechanism of cold tolerance in the Yunwu Tribute Tea. Hence, in this study, Illumina HiSeq technology was applied to investigate the cold-tolerance mechanism and for this purpose, cDNA libraries were obtained from two groups of samples namely, the cold-treated group (DW) and the control group (CK). A total of 185,973 unigenes were produced from 511,987 assembled transcripts and among these, 16,020 differentially expressed genes (DEGs) (corrected p-value <0.01, |log2(fold change)| >3), including 9,606 upregulated and 6,414 downregulated genes, were obtained. Moreover, the antioxidant enzyme system, plant hormone signal transduction, proline metabolism, tyrosine metabolism pathway, and transcription factors were analyzed and based on the results, a series of candidate genes related to cold stress were screened out and discussed. The physiological indexes related to the low temperature response were tested, along with five DEGs which were validated by quantitative real-time PCR. For this study, it is expected that the results of the transcriptome sequence of Yunwu Tribute Tea will provide valuable clues for genetic studies while helping to screen candidate genes for cold-resistance breeding in tea plants.

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