Effect of drought on photosynthesis, total antioxidant capacity, bioactive component accumulation, and the transcriptome of Atractylodes lancea

Abstract

Background Atractylodes lancea (Thunb.) DC, a medicinal herb belonging to the Asteraceae family, often faces severe drought stress during its growth. Until now, there has been no research on the effect of drought stress on the quality formation of A. lancea. Therefore, the present study aimed to study the effects of drought stress on A. lancea through physical and chemical analysis, and to reveal the related molecular mechanisms via transcriptome analysis. Results The photosynthesis was markedly inhibited under drought stress. There were alterations to photosynthetic parameters (Pn, Gs, Ci) and chlorophyll fluorescence (Fv/Fm, NPQ), and the chlorophyll content decreased. Twenty genes encoding important regulatory enzymes in light and dark reactions, including the Rubisco gene of the Calvin cycle, were significantly downregulated. After exposure to drought stress for more than 4 days, the activities of four antioxidative enzymes (SOD, POD CAT and APX) began to decrease and continued to decrease with longer stress exposure. Meanwhile, most of the genes encoding antioxidative enzymes were downregulated significantly. The downregulation of 21 genes related to the respiratory electron transport chain indicated that the blocked electron transfer accelerated excessive ROS. The MDA content was significantly elevated. The above data showed that 15 days of drought stress caused serious oxidative damage to A. lancea. Drought stress not only reduced the size and dry weight of A. lancea, but also lowered the amount of total volatile oil and the content of the main bioactive components. The total volatile oil and atractylodin content decreased slightly, whereas the content of atractylon and β-eudesmol decreased significantly. Moreover, ten significantly downregulated genes encoding sesquiterpene synthase were mainly expressed in rhizomes. Conclusions After exposed to drought stress, the process of assimilation was affected by the destruction of photosynthesis; stress tolerance was impaired because of the inhibition of the antioxidative enzyme system; and bioactive component biosynthesis was hindered by the downregulation of sesquiterpene synthase-related gene expression. All these had negative impacts on the quality formation of A. lancea under drought stress.

Genome-Wide Analysis of the WRKY Gene Family in Malus domestica and the Role of MdWRKY70L in Response to Drought and Salt Stresses

“…For example, when subjected to drought stress, plants change their rate of respiration and photosynthesis. They slow down transpiration by controlling stomatal conductance, thus retaining moisture [ 1 , 2 , 3 ]. Salt stress is one of the most important abiotic stressors, which leads to ion imbalance and water loss through osmotic reactions [ 4 , 5 ].…”

Tetraploidy in Citrus wilsonii Enhances Drought Tolerance via Synergistic Regulation of Photosynthesis, Phosphorylation, and Hormonal Changes

“…Consistent with our results, Shi et al (2021) reported that photosynthetic parameters (P n , gs, C i , and T r ) and water potential were all decreased in Hordeum jubatum seedlings under drought stress. In addition, Zhang et al (2021) reported that drought stress caused declines in the chlorophyll content, P n and Gs values, and F v /F m ratio in Atractylodes lancea . However, it is worth noting that a lesser decline for these parameters (except T r ) was observed in tetraploids compared to the diploids, suggesting that tetraploid rootstock maintains higher photosynthetic activities after drought stress in our study ( Figure 5 ).…”

Physiological and transcriptome analyses reveal the photosynthetic response to drought stress in drought-sensitive (Fengjiao) and drought-tolerant (Hanjiao) Zanthoxylum bungeanum cultivars

“…The light energy is absorbed by LHCs and subsequently transferred to the photosynthesis reaction center (Huang et al, 2021). Photosynthesis is highly sensitive to water deficit, which is generally weakened under drought stress (Ma et al, 2016;Zhang et al, 2021). As known, stomata are highly sensitive to drought stress (Zhang et al, 2021).…”

“…Photosynthesis is highly sensitive to water deficit, which is generally weakened under drought stress (Ma et al, 2016;Zhang et al, 2021). As known, stomata are highly sensitive to drought stress (Zhang et al, 2021). Given that stomata are channels for gas exchange in photosynthesis, closure or partial closure of stomata by drought stress largely reduced intercellular carbon dioxide (CO 2 ) concentration and sequenced inhibited photosynthesis.…”

“…For instance, Ma et al reported that the chlorophyll content in alfalfa declines significantly under drought stress (Ma et al, 2021). Zhang et al explored the effects of drought on photosynthesis by measuring photosynthetic parameters and conducting transcriptome analysis in Atractylodes lancea (Zhang et al, 2021). Daszkowska-Golec et al analyzed the physiological and genetic basis of photosynthesis in barley under drought stress (Daszkowska-Golec et al, 2019).…”