The PtoABCG36 transcript can be detected in leaves, stems and roots, and the expression in the root was 3.8 and 2 times that of stems and leaves, respectively. The higher expression level in the roots indicated that PtoABCG36 mainly functioned in the roots (Figure 2A). Compared to the control, where GFP was observed at the plasma membrane (PM), endoplasmic reticulum (ER) and nucleus (NU) in epidermal cells (Figure 3A–D), the PtoABCG36 signal was only observed at the plasma membrane (Figure 3E–H), indicating indicates that PtoABCG36 is localized at the plasma membrane to function as a transporter, consistent with the localization pattern of AtABCG36 in Arabidopsis thaliana.
In the absence of Cd, there was no growth difference between the PtoABCG36-bearing yeast and the control (Figure 4B). We tested Cd concentration in the yeast cells grown in liquid SD-Ura medium containing 40μM CdCl2. To elucidate the detoxification mechanism of PtoABCG36 in plants, we tested the cadmium content of the mutants, wild-type and transgenic plants after treatment with the half MS liquid medium containing 100μM CdCl2 for 24 h.
Net Cd2+ fluxes in the roots of WT,abcg36mutants and transgenic plants (OX-1, OX-2 and OX-3) treated with CdCl2stress (A). Expression pattern showed that the accumulation of PtoABCG36 transcript was mainly detected in the roots (Figure 2A).
Comparative Transcriptomic Studies on a Cadmium Hyperaccumulator Viola baoshanensis and Its
- Introduction
- Results
- Discussion
- Materials and Methods
- Conclusions
We compared the Cd concentrations in the roots (Figure 1a) and shoots (Figure 1b) and the tolerance indices (ratio of total dry biomass in the Cd treatments and controls) in the roots and shoots of the two Cd-treated Viola species ( Figure 1c) calculated. In total, 570 and 403 transcripts in the orthologous gene sets were differentially induced in response to Cd between the two Viola species in roots and shoots, respectively (see detailed information in Tables S9 and S10). These DEGs in the UPS pathway were further compared between the two phenotypes (Figure 4; Tables S3, S4 and S11).
DEGs involved in the ubiquitin proteasome system (UPS) pathway with constitutively higher transcript levels in Viola baoshanensis. For interspecies comparisons, we found that a total of 40 genes, encoding 19 enzymes in the starch and sucrose metabolism pathway, presented higher transcript levels in V. For a comparison in Cd-treated samples and controls, many genes were upregulated in response to Cd stress in roots (41 vs. 50) and shoots (22 vs. 33) of V .
As shown in Figure 3, a cascade of genes involved in the UPS pathway constitutively showed higher transcription levels and greater activation in response to Cd stress inV. Volcano plots of gene transcription level changes in the two Viola species with different Cd treatments (from 0 μM to 100 μM). The cell wall of early and later divergent plants versus cadmium toxicity: differences in the response mechanisms. Front.
Molecular physiology of heavy metal transport in the Zn/Cd hyperaccumulator Thlaspi caerulescens.Proc.
Exogenous Glycinebetaine Reduces Cadmium Uptake and Mitigates Cadmium Toxicity in Two Tobacco
Genotypes Differing in Cadmium Tolerance
Different patterns of the influence of Cd toxicity on the activities of ROS-scavenging enzymes, such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were found [ 11 - 13 ]. Therefore, to verify the hypothesis that some antioxidants may also be sensitive targets of Cd toxicity in addition to their function in detoxification in plants, Cd-induced changes in oxidative stress and antioxidant systems are imperative to determine. 21] observed that exogenous GB and trehalose reduced the deleterious effects of Cd stress in duckweed (Lemna gibba).
It is also of great importance to understand whether exogenous GB can be used as a regulator of Cd stress or as an antioxidant intervention strategy in preventing oxidative stress in response to Cd stress, in order to better understand how plants adapt to adverse environments. The present study was conducted through a hydroponic experiment to investigate the potential role of exogenous GB in mitigating Cd-induced changes in antioxidant metabolism, ultrastructure, photosynthesis, and chlorophyll fluorescence of two Cd-sensitive tobacco cultivars (cv.Guiyan1) and Cd-tolerant (cv.Yunyan2). Red fluorescence was very low, but detectable levels of red fluorescence were observed in Cd + GB roots.
Effect of exogenous Cd and GB on MDA accumulation and certain antioxidant enzyme activities Cd treatment showed a significant accumulation of MDA in tobacco seedlings, which was reduced by the application of exogenous GB (Supplementary Figure S1). Many studies have been reported on the interaction between the uptake and distribution of Cd and essential mineral elements in crops, but the results are inconsistent. Previous studies have shown that Zn, Mn and Cu interfere with Cd uptake and translocation from roots to shoots [24,25].
However, Guiyan1 had higher gs and Tr than Yunyan2 under Cd + GB, suggesting that a Cd-induced photosynthetic system impairment was rehabilitated by exogenous GB reinforcement, possibly by maintaining the photosynthetic capacity by regulating stomatal conductance and the transpiration rate to lower, which in turn opposes the absorption of Cd. All the measurements were performed with the upper second fully extended leaves after 15 days of Cd treatments. To evaluate cell viability, after 15 days of Cd exposure, the root tips were rinsed 3 times with deionized water and gently dried, then treated by staining with fluorescein diacetate and propidium iodide (FDA-PI) for 40 minutes, and washed 3 times with deionized water for 5 min.
The relief mechanism of GB to Cd stress is associated with (1) a reduced Cd accumulation and a balanced nutrient status; (2) the amelioration of Cd-induced damage to leaf and root ultrastructure, an improved membrane stabilizing/integrity, an increased SPAD value, and chlorophyll fluorescence including Fv/Fm, Fo and Fm in both cultivars and Pn in Yunyan2; (3) the partially reversed Cd-induced changes in antioxidant enzyme activities and suppressed MDA content compared to Cd alone treatment. Ultimately, the reduction of Cd by GB is expected to make contributions to the reduction of Cd toxicity to humans. Control, GB, Cd and Cd + GB correspond to BNS + foliar spray of deionized water, BNS + foliar spray of 500μM GB, BNS + foliar spray of deionized water + 5μM CdCl2, and BNS + foliar spray of 500μM GB + 5μM CdCl2, respectively. Figure S3.The effects of Cd and exogenous GB application on the photosynthesis parameters of two tobacco cultivars after 15 days of Cd exposure: The error bars represent the SD values (n= 3).
Genotypic differences in effect of Cd on growth and mineral concentrations in barley seedlings.Bull. Cadmium-induced inhibition of photosynthesis and long-term acclimation to cadmium stress in the hyperaccumulator Thlaspicaerulescens.
Transcriptome Analysis Reveals Cotton
Gossypium hirsutum) Genes That Are Differentially Expressed in Cadmium Stress Tolerance
Previous studies of Cd stress in cotton have mainly focused on physiological and biochemical aspects. In this study, DEGs were investigated and a regulatory network under Cd stress was constructed by sequencing the cotton transcriptome, and the gene function of GhHMAD5 was confirmed. Venn diagrams showing unique and common regulated genes in roots, stems and leaves of cotton under Cd stress;.
A large proportion of these 56 degrees was clearly expressed in the stem, which maintained its consistency with continued Cd tension. These data supported the fact that the root responded first and strongly to Cd stress. Similar molecular biological processes and molecular functions were observed in cotton roots, stems and leaves under Cd stress.
Figure 6A shows the total number of genes responsive to Cd stress in roots, stems and leaves with a Venn diagram. The expression level of the GhHMAD5 gene in plants was significantly decreased upon exposure to Cd stress (Fig. 9B). In this study, we detected a range of phenotypic symptoms of cotton root system under Cd stress (Fig. 1A).
In this study, transcriptome analysis of roots, stems, and leaves of cotton under Cd stress was performed. Gh_D12G1971 was highly expressed in roots, stems, and leaves of cotton under Cd stress, indicating that the HSP protein is related to Cd stress. Detoxification complexation, thickening of physical barriers, and oxidative stress were the main mechanisms in Cd-stressed cotton [ 47 ].
In this study, we found GhHMAD5 plays an important role in cotton under Cd stress. According to the DEGs in cotton, we identified the main factors of cotton tolerance to Cd stress (Figure 13). This study suggests that DNA methylation is an important mechanism among complex pathways under Cd stress in plants.
All samples were dried in an oven at 80 °C for 3 days, followed by measurement of Cd content under Cd stress and controls. In this study, 11,503 DEGs were detected under Cd stress in cotton by RNA-Seq analysis.
