Boea hygrometrica resurrection plants require a period of acclimation by slow soil-drying in order to survive a subsequent period of rapid desiccation. The molecular basis of this observation was investigated by comparing gene expression profiles under different degrees of water deprivation. Transcripts were clustered according to the expression profiles in plants that were air-dried (rapid desiccation), soil-dried (gradual desiccation), rehydrated (acclimated) and air-dried after acclimation. Although phenotypically indistinguishable, it was shown by principal component analysis that the gene expression profiles in rehydrated, acclimated plants resemble those of desiccated plants more closely than those of hydrated acclimated plants. Enrichment analysis based on gene ontology was performed to deconvolute the processes that accompanied desiccation tolerance. Transcripts associated with autophagy and α-tocopherol accumulation were found to be activated in both air-dried, acclimated plants and soil-dried non-acclimated plants. Furthermore, transcripts associated with biosynthesis of ascorbic acid, cell wall catabolism, chaperone-assisted protein folding, respiration and macromolecule catabolism were activated and maintained during soil-drying and rehydration. Based on these findings, we hypothesize that activation of these processes leads to the establishment of an optimal physiological and cellular state that enables tolerance during rapid air-drying. Our study provides a novel insight into the transcriptional regulation of critical priming responses to enable survival following rapid dehydration in B. hygrometrica.

Verticillium wilt, caused by Verticillium dahliae , seriously limits cotton production. It is difficult to control this pathogen damage mainly due to the complexity of the molecular mechanism of plant resistance to V. dahliae . Here, we identified three homologous cotton Walls Are Thin ( WAT ) genes, which were designated as GhWAT1, GhWAT2 , and GhWAT3. The GhWATs were predominantly expressed in the roots, internodes, and hypocotyls and induced by infection with V. dahliae and treatment with indole-3-acetic acid (IAA) and salicylic acid (SA). GhWAT1 -, GhWAT2 -, or GhWAT3 -silenced plants showed a comparable phenotype and level of resistance with control plants, but simultaneously silenced three GhWATs ( GhWAT123 -silenced), inhibited plant growth and increased plant resistance to V. dahliae , indicating that these genes were functionally redundant. In the GhWAT123 -silenced plants, the expression of SA related genes was significantly upregulated compared with the control, resulting in an increase of SA level. Moreover, the histochemical analysis showed that xylem development was inhibited in GhWAT123 -silenced plants compared with the control. However, lignin deposition increased in the xylem of the GhWAT123 -silenced plants compared to the control, and there were higher expression levels of lignin synthesis- and lignifications-related genes in the GhWAT123 -silenced plants. Collectively, the results showed that GhWATs in triple-silenced plants acts as negative regulators of plant resistance against V. dahliae. The potential mechanism of the WATs functioning in the plant defence can modulate the SA biosynthesis and lignin deposition in the xylem.

Arsenic (As) speciation and distribution are two important factors in assessing human health risk from As-contaminated soil. In this study, we used the combination of physiologically based extraction test (PBET) and Simulator of Human Intestinal Microbial Ecosystem (SHIME) to determine soil As metabolism by human gut microbiota. The results showed that the percentage of soil arsenate [As(V)] transformation reached 22.1−38.2%, while that of arsenite [As(III)] attained 66.5−92.0%; 30.1−56.4% of As(V) transformed was attached to the soil solid phase. In comparison to sequential extraction results, almost all amorphous Fe/Al-oxide-bound As was liberated in the colon phase. An X-ray absorption nearedge structure (XANES) showed that the As(III) percentage in the soil solid phase reached 16.6−26.9% and reached 73.4% (soil 1) in the colon phase. Additionally, plenty of As(III) and different extents of methylation were also observed in colon extraction solution. As bioaccessibility in the colon phase was 1.8−2.8 times that in the small intestinal phase. Our results indicated that human gut microbiota increased As bioaccessibility, and large amounts of As(III) were adsorbed onto the soil solid phase as a result of microbial reduction. Determining As speciation and distribution in extraction solution and soil solid phases will allow for an accurate assessment of the risk to human health upon soil As exposure. ■ INTRODUCTIONArsenic (As) is a common toxic contaminant that is extensively distributed in the environment. 1 Human exposure to As in soils is a major public concern and is associated with serious risks to human health because As species are known carcinogens. 2,3 In most cases, human exposure to soil As occurs via inhalation, inadvertent oral ingestion, and dermal contact. 4,5 Inadvertent oral ingestion has been considered an important exposure route for soil As, especially ingestion through outdoor hand-to-mouth activities by children. 6 The estimation of As bioaccessibility (gastric and small intestinal phases) in contaminated soils through in vitro methods has been used for human health risk assessment. On the basis of previous studies, 7−9 simple, fast, and inexpensive in vitro methods can effectively estimate in vivo relative As bioavailability. Generally, bioaccessibility is defined as the fraction of As that is soluble in the gastrointestinal environment of humans and available for absorption, whereas bioavailability is determined by the fraction of As that is absorbed into the systemic circulation. 7,8 Currently, As bioaccessibility in the gastric and small intestinal phases may underestimate its harm to human health. 10 Studies have clearly illustrated that gut microbiota significantly affect As metabolism by, for example, reduction, methylation, and thiolation. 11 As metabolism in contaminated soil by human gut microbiota can affect As bioaccessibility and speciation. 10,12 Therefore, As biotransformation must be considered an essential part of the risk assessment of oral soil As exposure using i...

The present study provides a new insight in understanding the mechanism of IVF-induced aberrations during embryonic development and the increased health risks in the offspring. In addition, we highlighted the possibility of improving existing IVF systems by modulating mitochondrial functions.

Gossypium hirsutum is an allotetraploid species, meaning that mutants that are difficult to be generated by classical approaches due to gene redundancy. The CRISPR/Cas9 genome editing system is a robust and highly efficient tool for generating target gene mutants, by which the genes of interest may be functionally dissected and applied through genotype-to-phenotype approaches. In this study, the CRISPR/Cas9 genome editing system was developed in G. hirsutum through editing the Gh14-3-3d gene. In T0 transgenic plants, lots of insertions and deletions (indels) in Gh14-3-3d at the expected target site were detected in the allotetraploid cotton At or Dt subgenomes. The results of the PCR, T7EI digestion and sequencing analyses showed that the indels in Gh14-3-3d gene can be stably transmitted to the next generation. Additionally, the indels in the At and Dt subgenomes were segregated in the T1 transgenic plants following Mendelian law, independing on the T-DNA segregation. Two homozygous Gh14-3-3d-edited plants free of T-DNA were chosen by PCR and sequencing assays in the T1 plants, which were called transgene-clean editing plants and were designated ce1 and ce2 in the T2 lines showed higher resistance to Verticillium dahliae infestation compared to the wild-type plants. Thus, the two transgene-clean edited lines can be used as a germplasm to breed disease-resistant cotton cultivars, possibly avoiding complex and expensive safety assessments of the transgenic plants.

• Five in vitro gastrointestinal methods combined with SHIME (colon phase) were used.• As bioaccessibility varied in the colon phase among these methods.• Plenty of As(III) and methylated arsenicals by microbial transformation were observed.• As bioaccessibility in PBET/SBRC-SHIME colon phase were closer to in vivo results for NIST 2710a. Arsenic (As) speciation analysis is essential when evaluating the risks upon oral exposure to As-contaminated soils. In this study, we first investigated the variability in the As bioaccessibility and speciation using a combination of five common in vitro methods (SBRC, PBET, DIN, UBM and IVG) (gastric and small intestinal phases) and the SHIME model (colon phase). Our results indicate that the As bioaccessibility varies in the colon phase. An increase in the As bioaccessibility for SBRC and PBET, and a decrease for UBM and IVG were observed in the colon phase. In addition, we found different extents of methylation and large amounts of arsenite [As(III)] due to microbial reduction in the colon digests. The UBM-SHIME method displayed a higher methylation percentage of 13.5-82.1%, but a lower methylation percentage of 0.2-21.8% was observed in the SBRC-SHIME method. Besides, The MMA V levels in the colon digests were positively correlated with those of As(III) and DMA V , so DMA V can be considered an indicator to evaluate the As metabolic speed of in vitro cultured human gut microbiota. Based on the standard reference soil of NIST 2710a, the As bioaccessibility in the colon phase of PBET-SHIME and SBRC-SHIME were the closest to the in vivo results. Combining in vitro methods and SHIME will remarkably affect the accurate assessment of potential risks to human health associated with oral exposure to soil As.

SUMMARYThis paper develops a practical approach to simulating fracture propagation in rock and concrete based on an augmented virtual internal bond (VIB) method in which the cohesion of solid is modeled as material particles interconnected by a network of randomized virtual micro bonds described by the XuNeedleman potential. The micro bond potential is used to derive macroscale constitutive relations via the Cauchy-Born rule. By incorporating different energy contributions due to stretch and shearing, as well as different energy levels under tension and compression of each micro bond, the derived macro constitutive laws are particularly useful for modeling quasi-brittle materials such as rock and concrete which usually have different Poisson ratios and much higher compressive strength than tensile strength. The mesh-size sensitivity associated with strain-softening in the present constitutive model is addressed by adjusting material constants near the crack tip so that the J-integral is kept equal to the intrinsic fracture energy of the material. Numerical examples demonstrate that the proposed VIB method is capable of simulating mixed mode fracture propagation in rock and concrete with results in consistency with relevant experimental observations.

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