1Selenium supply alters the subcellular distribution and chemical forms of cadmium and the expression of transporter genes involved in cadmium uptake and translocation in winter wheat (Triticum aestivum)

Abstract

Background Cadmium (Cd) accumulation in crops affects the yield and quality of crops and harms human health. The application of selenium (Se) can reduce the absorption and transport of Cd in winter wheat. Results The results showed that increasing Se supply significantly decreased Cd concentration and accumulation in the shoot and root of winter wheat and the root-to-shoot translocation of Cd. Se application increased the root length, surface area and root volume but decreased the average root diameter. Increasing Se supply significantly decreased Cd concentration in the cell wall, soluble fraction and cell organelles in root and shoot. An increase in Se supply inhibited Cd distribution in the organelles of shoot and root but enhanced Cd distribution in the soluble fraction of shoot and the cell wall of root. The Se supply also decreased the proportion of active Cd (ethanol-extractable (FE) Cd and deionized water-extractable (FW) Cd) in root. In addition, the expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 significantly increased with increasing Cd concentration in root, and the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root was downregulated by increasing Se supply, regardless of Se supply or Cd stress. The expression of TaHMA3-b in root was significantly downregulated by 10 μM Se at both the 5 μM and 25 μM Cd level but upregulated by 5 μM Se at the 25 μM Cd level. The expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 in shoot was downregulated by increasing Se supply at 5 μM Cd level, and 5 μM Se upregulated the expression of those genes in shoot at 25 μM Cd level. Conclusions The results confirm that Se application limits Cd accumulation in wheat by regulating the subcellular distribution and chemical forms of Cd in winter wheat tissues, as well as the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root.

Comparing de novo transcriptome assembly tools in di- and autotetraploid non-model plant species

“…While all assemblers produced less than 65,000 transcripts for both, di- and autotetraploid A. thaliana , the number of transcripts in the Acer and Vaccinium assemblies was multiple times higher ranging from 134,424 up to around 355,230 in case of the diploids, and from around 280,852 to more than 735,465 in the autotetraploids. That tendency is surprising because the number of genes in some Vaccinium and Acer species is estimated only to be in the range or utmost twice the number of the 27,000 annotated genes in A. thaliana [ 37 , 49 – 51 ]. Of course, one should be aware that this is only an estimation and could be underestimated for Acer and Vaccinium due to the lack of completely sequenced and annotated genomes for those genera [ 52 ].…”

“…Both species show a similar distribution pattern across Europe and are valuable hardwood species [ 35 , 36 ]. Further, Vaccinium is a young and widespread genus with elevated rates of speciation in recent decades that led to the formation of about 450 species [ 37 ]. The genus includes blueberries, cranberries or lingonberries and consists of very complex polyploid species like Vaccinium corymbosum L., a highly economically relevant species in the food sector [ 37 , 38 ].…”

“…Further, Vaccinium is a young and widespread genus with elevated rates of speciation in recent decades that led to the formation of about 450 species [ 37 ]. The genus includes blueberries, cranberries or lingonberries and consists of very complex polyploid species like Vaccinium corymbosum L., a highly economically relevant species in the food sector [ 37 , 38 ]. In addition, to have a proven reference, a di- and an autotetraploid Arabidopsis thaliana L. genotype was included in our study.…”

Silicon-Selenium Interplay Imparts Cadmium Resistance in Wheat through an Up-Regulating Antioxidant System

“…The comparatively highest significant ( p < 0.05) effect was noticed upon co-application of Se + Si treatment followed by Se treatment, respectively ( Table 1 ). The increase in plant biomass upon co-application of Se + Si may be attributed to Se-induced plant physiological and enzymatic regulation against Cd-induced oxidative and metabolic damages [ 20 ] and plant morphological adaptations to reduce Cd uptake and structural damages [ 19 ]. Abdalla et al [ 15 ] also revealed a positive impact of Se on water-soluble sugars under S-deficient conditions in Lettuce.…”

“…Se/Si treatments also increased grain yield, antioxidant enzyme activities, and reduced MDA in wheat tissues [ 21 ]. Past studies reported that Se applications were more effective than Si on plant physiological growth under Cd stress [ 16 , 20 ]. In contrast, our study indicated significant p < 0.05 plant physiological growth with Si and Si + Se treatments under Cd stress.…”