Abiotic stress-induced changes in Tetrastigma hemsleyanum: insights from secondary metabolite biosynthesis and enhancement of plant defense mechanisms

Abstract

Tetrastigma hemsleyanum, a traditional Chinese medicinal plant with anti-inflammatory, anti-cancer, and anti-tumor properties, faces increasing abiotic stress due to climate change, agricultural chemicals, and industrialization. This study investigated how three abiotic stress factors influence antioxidant enzyme activity, MDA levels, DPPH free radical scavenging capacity, chlorophyll, carotenoids, active compounds, and gene expression in different T. hemsleyanum strains. The comprehensive evaluation indicates that the ZJWZ strain holds potential as a preferred parental material for future resistance breeding. Furthermore, PAL gene expression was strongly positively correlated with flavonoid and phenol contents, highlighting its role in the stress response through the phenylpropanoid-flavonoid pathway. This study contributes to the standardization of the production and breeding of superior strains of T. hemsleyanum. It also lays the foundation for investigating how plants react to environmental stressors.

Keywords: Tetrastigma hemsleyanum; Environmental signal response; Phytochemical composition; Plant growth and development; Stress resistance.

Fig. 1

T. hemsleyanum growth condition under different abiotic stress treatments

Fig. 2

Effects of cadmium stress of T. hemsleyanum on antioxidant enzyme activities. (a) APX activity, (b) CAT activity, (c) POD activity, (d) SOD activity. Data were the means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at P < 0.05 levels by Duncan’s multiple range tests

Fig. 3

Effects of salt stress of T. hemsleyanum on antioxidant enzyme activities. (a) APX activity, (b) CAT activity, (c) POD activity, (d) SOD activity. Data are the means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at level of P < 0.05 by Duncan’s multiple range tests

Fig. 4

Effects of cold stress of T. hemsleyanum on antioxidant enzyme activities. (a) APX activity, (b) CAT activity, (c) POD activity, (d) SOD activity. Data are the means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at P < 0.05 by Duncan’s multiple range tests

Fig. 5

Effects of abiotic stresses of T. hemsleyanum on MDA content and DPPH free radical scavenging. (a) MDA content (cadmium stress), (b) MDA content (salt stress), (c) MDA content (cold stress), (d) DPPH% (cadmium stress), (e) DPPH% (salt stress), (f) DPPH% (cold stress). Data are the means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at P < 0.05 levels by Duncan’s multiple range tests

Fig. 6

Effects of abiotic stresses of T. hemsleyanum on carotenoid and total chlorophyll contents. (a) Carotenoid content (cadmium stress), (b) Total chlorophyll content (cadmium stress), (c) Carotenoid content (salt stress), (d) Total chlorophyll content (salt stress), (e) Carotenoid content (cold stress), (f) Total chlorophyll content (cold stress). Data are means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at P < 0.05 levels by Duncan’s multiple range tests

Fig. 7

Effects of cadmium stress in T. hemsleyanum on total flavonoids, phenolic and polysaccharide contents. (a) Total polysaccharide content; (b) Total phenolic content; (c) Total flavonoid content. Data are the means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at P < 0.05 levels by Duncan’s multiple range tests

Fig. 8

Effects of salt stress of T. hemsleyanum on total flavonoids, phenolic and polysaccharide contents. (a) Total polysaccharide content; (b) Total phenolic content; (c) Total flavonoid content. Data are the means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at P < 0.05 levels by Duncan’s multiple range tests

Fig. 9

Effects of cold stress of T. hemsleyanum on total flavonoids, phenolic and polysaccharide contents. (a) Total polysaccharide content; (b) Total phenolic content; (c) Total flavonoid content. Data are the means of three replicates (mean ± SE). Values followed by different letters indicate significant difference at P < 0.05 levels by Duncan’s multiple range tests

Fig. 10

Cluster heatmap analysis of abiotic stresses on the contents of five active compounds in T. hemsleyanum. In the heat map, the rows represent the main active components of the five T. hemsleyanum strains and the columns represent different abiotic stress levels, which were normalized. The level of each active component content was represented by the size of the circle area. The Z-Score Normalization was performed by row. A z score less than 0 represents an element less than the mean, denoted “-” in blue, while a score greater than 0 is designated “+ " in red. A positive z-score indicates the raw value is higher than the mean average. A negative z-score reveals the raw value is below the mean average. The samples were also clustered according to the active component content of each sample

Fig. 11

Heatmap of related genes expression of T. hemsleyanum under abiotic stresses. Data are the means of three replicates (mean ± SE). The expression level of the control group was normalized to “1”. Drawing heat map using expression data processed by log2

Fig. 12

Pearson’s correlation coefficient and significance of gene expression and biological indexes of T. hemsleyanum. The Pearson correlation coefficient ranges between 1 and − 1, with 1 representing a perfect positive correlation in deep red and − 1 representing a perfect negative correlation in dark blue. “*” indicates P < 0.05, which is significant; “**” indicates P < 0.01, which is highly significant; “***” indicates P < 0.001, which is extremely significant; and “****” indicates P < 0.0001, which is very highly significant