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Soil heavy metal pollution is one of the most challenging problems. Kenaf is an important natural fiber crop with strong heterosis and a higher tolerance to heavy metals. However, little is known about the molecular mechanisms of kenaf heavy metal tolerance, especially the mechanism of genomic DNA methylation regulating heterosis. In this study, kenaf cultivars CP085, CP089, and their hybrid F 1 seedlings were subjected to 300 µM cadmium stress and found obvious heterosis of cadmium resistance in morphology and antioxidant enzyme activity of F 1 hybrid seedlings. Through methylation-sensitive amplification polymorphism (MSAP) analysis, we highlighted that the total DNA methylation level under cadmium decreased by 16.9 % in F 1 and increased by 14.0 % and 3.0 % in parents CP085 and CP089, respectively. The hypomethylation rate was highest (21.84 %), but hypermethylation was lowest (17.24 %) in F 1 compared to parent cultivars. In particular, principal coordinates analysis (PCoA) indicates a significant epigenetic differentiation between F 1 and its parents under cadmium. Furthermore, 21 differentially methylated DNA fragments (DMFs) were analyzed. Especially, the expression of NPF2.7 , NADP-ME , NAC71 , TPP-D , LRR-RLKs, and DHX51 genes were changed due to cadmium stress and related to cytosine methylation regulation. Finally, the knocked-down of the differentially methylated gene NPF2.7 by virus-induced gene silencing (VIGS) resulted in increased sensitivity of kenaf seedlings under cadmium stress. It is speculated that low DNA methylation levels can regulate gene expression that led to the heterosis of cadmium tolerance in kenaf. • Kenaf hybrid showed significant heterosis to Cd stress and with enhanced Cd transport capacity compared with its parents. • The stronger anti-oxidant ability is positively related to F 1 seedling heterosis under Cd stress. • MSAP revealed the down regulation total DNA methylation increased F 1 Cd tolerance capacity. • The expression of key genes including NPF2.7 , NADP-ME , NAC71 , TPP-D , LRR-RLKs and DHX51 were involved in plant growth and Cd stress response. • VIGS of gene NPF2.7 increased kenaf to Cd tolerance. [ABSTRACT FROM AUTHOR]

Environmentally friendly BiFeO 3 -based capacitors have attracted great attention in energy storage applications. Herein, a large W rec of 2.91 J/cm3 and a high η of 85% were obtained under the electric field of 220 kV/cm in (1-x)(0.67BiFeO 3 -0. 3 3BaTiO 3)-xSr 0.7 Sm 0.2 TiO 3 (BF-BT-xSST) ceramics at x = 0.30. The addition of SST facilitates to enhance the relaxor behavior and suppress the early polarization saturation of ceramics. The breakdown strength of BF-BT-xSST ceramics is enhanced due to the significantly decreased grain size and the increased band gap. More importantly, the BF-BT-0.30SST ceramic exhibits an excellent fatigue endurance (< 1.1%, after 105 fatigue cycles), which is superior to most of previous works. In addition, BF-BT-0.30SST ceramic also shows high thermal and frequency stability, and fast discharge rate (t 0.9 < 0.16 μs). We propose that the SST or a combination of SST and Sr 0.7 Bi 0.2 TiO 3 is a better additive for the BF-based energy storage materials. [ABSTRACT FROM AUTHOR]

Soil cadmium (Cd) contamination has become a massive environmental problem. Kenaf is an industrial fiber crop with high tolerance to heavy metals and could be potentially used for soil phytoremediation. However, the molecular mechanism of Cd in kenaf tolerance remains largely unknown. In the present study, using two contrasting Cd sensitive kenaf (GH and YJ), the key factors accounting for differential Cd tolerance were investigated. GH has a stronger Cd transport and accumulation ability than YJ. In addition, physiological index investigation on malondialdehyde (MDA) contents and antioxidant enzyme (SOD, POD, and CAT) activities showed GH has a stronger detoxification capacity than YJ. Furthermore, the cell ultrastructure of GH is more stable than that of YJ under Cd stress. Transcriptome analysis revealed 2221 (689 up and 1532 down) and 3321 (2451 up and 870 down) genes were differentially expressed in GH and YJ, respectively. More DEGs (differentially expressed genes) were characterized as up-regulated in GH, indicating GH is inclined to activate gene expression to cope with cadmium stress. GO and KEGG analyses indicate that DEGs were assigned and enriched in different pathways. Plenty of critical Cd-induced DEGs such as SOD2, PODs, MT1, DTXs, NRT1, ABCs, CES, AP2/ERF, MYBs, NACs, and WRKYs were identified. The DEGs involved pathways, including antioxidant, heavy metal transport or detoxification, substance transport, plant hormone and calcium signals, ultrastructural component, and a wide range of transcription factors were suggested to play crucial roles in kenaf Cd tolerance, and accounting for the difference in Cd stress sensitivities. Image 1 • First, comparative and integrative study on molecular basis of Cd tolerance in kenaf. • Different strategies were engaged to cope with Cd-stress in two kenaf cultivars. • Key factors such as ROS elimination, HM detoxification etc. account for Cd tolerance. • Critical Cd-responsive genes and metabolic pathways were characterized in kenaf. • Lay a foundation for dissecting the molecular mechanism of Cd stress. [ABSTRACT FROM AUTHOR]

Anthocyanins are a flavonoid compound known as one of the most important chromogenic substances. They play several functions, including health promotion and sustaining plants during adverse conditions. They are synthesized at the endoplasmic reticulum and sequestered in the vacuole. In this work, we generated knock-out lines of OsGSTU34, a glutathione transporter's tau gene family, with no transgene line and off-target through CRISPR/Cas9 mutagenesis and highlighted the loss of pigmentation in rice flowers, leaves, stems, shoots, and caryopsis. The anthocyanin quantification in the wild-type BLWT and mutant line BLG34-8 caryopsis showed that cyanidin-3-O-glucoside (C3G) and peonidin-3-O-glucoside (P3G) were almost undetectable in the mutant line. A tandem mass tag (TMT) labeling proteomic analysis was conducted to elucidate the proteomic changes in the BLWT and BLG34-8. The result revealed that 1175 proteins were altered, including 408 that were down-regulated and 767 that were upregulated. The accumulation of the OsGSTU34 -related protein (Q8L576), along with several anthocyanin-related proteins, was down-regulated. The enrichment analysis showed that the down-regulated proteins were enriched in different pathways, among which the phenylpropanoid biosynthesis pathway, flavonoid biosynthesis metabolites, and anthocyanin biosynthesis pathway. Protein interaction network prediction revealed that glutathione-S-transferase (Q8L576) was connected to the proteins involved in the flavonoid and anthocyanin biosynthesis pathways, such as flavanone 3-dioxygenase 1 (Q7XM21), leucoanthocyanidin dioxygenase 1 (Q93VC3), 4-coumarate-CoA ligase 2 (Q42982), phenylalanine ammonia-lyase (P14717), chalcone synthase 1 (Q2R3A1), and 4-coumarate-CoA ligase 5 (Q6ZAC1). However, the expression of the most important anthocyanin biosynthesis gene was not altered, suggesting that only the transport mechanism was affected. Our findings highlight new insight into the anthocyanin pigmentation in black rice and provide new perspectives for future research. CRISPR/Cas9 gene editing targeting OsGSTU34 , a Bz2-like anthocyanin-related glutathione transferase transporter, greatly affects pigmentation in different parts of black rice. The two main anthocyanins in black rice, identified as cyanidin-3-O-glucoside (C3G) and peonidin-3-O-glucoside (P3G), were almost undetectable in the mutant line Osgstu34. [Display omitted] • Anthocyanins are phytochemicals responsible for black rice (O. sativa L.) pigmentation. • Cyanidin-3-O-glucoside (C3G) and peonidin-3-O-glucoside (P3G) are the main anthocyanins in black rice. • The knockout of OsGSTU34 causes loss of pigmentation in different parts of black rice. • The amounts of C3G and P3G were almost undetectable in the mutant-type Osgstu34. • The loss of function of OsGSTU34 may not affect anthocyanin biosynthesis but only accumulation. [ABSTRACT FROM AUTHOR]

High salinity is one of the major abiotic stresses that limit crop production. Salicylic acid (SA) has been shown to ameliorate the adverse effects of environmental stress on plants. However, the molecular basis of salicylic acid-mediated salinity tolerance in kenaf is still unclear. To uncover the toxic alleviation effects of SA on kenaf salt stress, the morphological, physiological indexes, and transcriptomic regulating were assayed under NaCl stress with (or without) SA pretreated. The result showed that application of exogenous SA significantly alleviated the repressive effects of kenaf under salt stress, including agronomic traits, antioxidant enzyme systems, and several important pathways and involved differentially expressed genes (DEGs). In addition, some transcription factors (TFs) such as NAC , MYB , bHLH , ERF and enzyme activity-related genes such POD were also significantly changed with exogenous SA application. Virus‑Induced Gene Silencing (VIGS) of a differentially expressed TFs , HcNAC29, reduced salt tolerance in kenaf. Integrating physiological and transcriptomic analyses, a number of important pathways were found to be important for SA-mediated salinity tolerance in kenaf, including phenylpropanoid biosynthesis, flavonoid biosynthesis, plant hormone signaling pathway, and some transcription factors such as NAC. The data presented here may be useful in further elucidating the multiple regulatory roles of SA in plant responses to abiotic stresses. • First, comparative and integrative study on molecular basis of SA (Salicylic acid) alleviate salt stress in kenaf. • SA elimination ROS and activated antioxidant system to alleviate salt stress. • Critical salt-responsive genes and metabolic pathways were characterized in kenaf. • Virus‑Induced Gene Silencing of HcNAC29 indicated it play key roles in kenaf salt tolerance. • Lay a foundation for dissecting the molecular mechanism of SA alleviate stress. [ABSTRACT FROM AUTHOR]

Soil Cadmium (Cd) contamination has become a severe environmental problem around the world. Kenaf has great potential for utilization and phytoremediation of soil contaminated with heavy metal. Arbuscular mycorrhizal fungi (AMF) can help plants alleviate Cd stress, but the underlying mechanism remains completely unknown. In this study, kenaf was inoculated or not inoculated with AMF at cadmium concentrations of 10 mg kg−1 and 50 mg kg−1 from the seedling stage to the vigorous growth stage. The results showed that AMF symbionts improved nutrient transport efficiency and significantly improved plant growth. Additionally, AMF colonization increased cell wall polysaccharide content which help to bind Cd in the cell wall and reduced the transport of Cd to aboveground plant tissues. The increase in soil pH (6.9), total balcomycin and easily extractable balcomycin content facilitated the chelation of metal by mycorrhizal fungi and reduced the biological effectiveness of Cd. Furthermore, AMF upregulated the expression levels of key kenaf genes, such as Hc.GH3.1, Hc.AKR, and Hc.PHR1 , which plays an important role in enhancing kenaf Cd tolerance. Our findings systematically revealed the mechanisms by which AMF responds to Cd stress in kenaf, inoculation of AMF with kenaf could be used to enhance the removal of Cd from soil pollution in mining areas by phytoremediation. [Display omitted] • AMF can alleviate kenaf Cd stress by reducing oxidant damage, improving photosynthetic capacity, and nutrient uptake. • AMF increase the polysaccharide content of cell wall to fix Cd in the roots and inhibit Cd transport to above ground plant parts. • AMF enhance balcomycin content in soil which facilitates chelation and reduces the biological effectiveness of Cd. • The up-regulation of the expression of genes, such as Hc.GH3.1, Hc.ARK, and Hc.PHR1 , contribute to the kenaf Cd tolerance. [ABSTRACT FROM AUTHOR]

As a toxic heavy metal, chromium (Cr) has become a major environmental concern in cultivated areas. Kenaf is a fast-growing fibre crop with high economic value and can potentially be used for phytoremediation. However, limited information is known regarding the mechanism of kenaf in response to Cr stress, especially from the perspective of epigenetics. The present study was conducted to explore the physiological and DNA methylation changes in kenaf seedlings grown under different concentrations (from 0 to 600 μM) of Cr stress. The results show that Cr reduced plant height, root length, biomass, and root cell viability compared with the control. The activities of antioxidant enzymes (SOD, POD, and CAT) increased under Cr stress and reached their peaks at Cr concentrations of 500, 300, and 400 μM respectively. Methylation-sensitive amplification polymorphism (MSAP) analysis revealed a significant positive correlation between an increase in the total DNA methylation level and Cr concentration, and the increasing rate ranged from 20.97% to 26.34%. Among the 205 loci examined, 40 differentially methylated DNA fragments (DMFs) were cloned and analysed. DMFs such as the ABC transport family (ABC) may play essential roles in kenaf Cr stress. In addition, the methylation status of three Cr stress- related DMFs (HcABC , HcRHP and HcTyDC) was investigated via the bisulfite sequencing polymerase chain reaction (BSP) method. Furthermore, knockdown of HcTyDC by virus-induced gene silencing (VIGS) led to increased sensitivity to Cr stress. Overall, our data indicate that higher antioxidant activity and increased cytosine methylation levels in the plant genome could be related to Cr tolerance mechanisms in kenaf, and these changes then affect the expression of specific genes involved in the Cr stress response. • The key responses of kenaf to Cr stress consisted of marked reduction in plant biomass and enhanced ROS generation. • Antioxidant enzymes play an important role in resisting damages caused by Cr stress for kenaf. • Cr exposure caused DNA methylation level rise, thus affecting many genes expression which are involved in kenaf Cr response. [ABSTRACT FROM AUTHOR]

Soil salinization is becoming a major threat to the sustainable development of global agriculture. Kenaf is an industrial fiber crop with high tolerance to salt stress and could be used for soil phytoremediation. However, the molecular mechanism of kenaf salt tolerance remains largely unknown. DNA methylation is an important epigenetic modifications phenomena and plays a key role in gene expression regulation under abiotic stress condition. In the present study, the kenaf seedlings were pre-treated or not with 50 μM 5-azacytidine (5-azaC, a DNA methylation inhibitor) and then subjected to different concentrations of NaCl. Results showed that the biomass and antioxidant activities (superoxide dismutase, peroxidase and catalase) of kenaf seedlings pre-treated with 5-azaC were significantly increased, while the contents of superoxide anion (O 2 −) and malondialdehyde (MDA) were decreased, indicating that 5-azaC pre-treatment could significantly alleviate salt stress injury. Furthermore, the methylation-sensitive amplified polymorphism (MSAP) analysis revealed that DNA methylation level of keanf seedlings pre-treated with 5-azaC significantly decreased. The expression of seven differentially methylated genes responsing to salt stress was significantly changed from real-time fluorescent quantitative (qRT-PCR) analysis. Finally, knocked-down of the l -ascorbate oxidase (L-AAO) gene by virus-induced gene silencing (VIGS) resulted in increased sensitivity of kenaf seedlings under salt stress. Overall, it was suggested that 5-azaC pre-treatment can significantly improve salt tolerance in kenaf by decreasing ROS content, raising anti-oxidant activities, and regulating DNA methylation and expression of stress-responsive genes. • Salt stress increased DNA methylation level in kenaf. • 5-azaC pretreatment improved kenaf salt tolerance. • 5-azaC pretreatment decreased DNA methylation and changed physiological indexes. • 5-azaC altered the methylation and thus activated salt-tolerant genes expression. • VIGS analysis suggested L-AAO gene positively regulates the salt resistance in kenaf. [ABSTRACT FROM AUTHOR]

• Kenaf has a high Cd tolerance and a strong Cd absorb and transport ability. • First, transcriptomic on molecular basis of Cd tolerance in kenaf. • Key Cd-responsive differentially expressed genes and pathways were identified. • Study lay a foundation to elucidate the molecular mechanisms of Cd tolerance. Kenaf (Hibiscus cannabinus L.) is an important natural fiber crop with great potential for Cd-polluted soil phytoremediation. However, little is known about the molecular mechanism of Cd tolerance in kenaf. To reveal this potential molecular mechanism, in the present study, kenaf cultivar FH991 was used for physiological and transcriptomic analysis under different concentration of Cd stress. Result should that kenaf exhibited strong Cd absorbance and transport ability. Under 10 mg L−1 Cd stress condition, the Cd content reached 1986.5 and 321.1 mg kg-1 in the root and shoot, respectively. Antioxidant enzyme activities, including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), were investigated. The result showed that enzyme activities increased and then decreased when plants were exposed to 10 and 30 mg L−1 Cd stress, respectively. Transcriptome sequencing generated approximately 35.2 GB of paired-end raw reads and de novo assembled to yield 105,437 unigenes in the root. A total of 3926 differentially expressed unigenes (DEGs) were identified under Cd stress, comprising 1206 upregulated and 2720 downregulated genes. Validation of 15 stress-responsive DEGs was authenticated by using real-time quantitative PCR. Gene ontology (GO) analysis showed that the DEGs were mainly involved in metabolic process, membrane component, and catalytic activity. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis showed that Cd stress caused changes in DEGs that were mainly involved in carbohydrate metabolism, replication and repair, signal transduction, transport and catabolism, and environmental adaptation. Key DEGsand their involved pathways in such as 'heavy metal transport and detoxification activity', 'ROS antioxidant activity', 'GAs and MAPK signaling', 'carbohydrate and energy metabolism' processes as well as a wide range of transcription factors were concluded to play vital roles in kenaf Cd tolerance. [ABSTRACT FROM AUTHOR]

• First, iTRAQ-based proteomic study on molecular basis of salt tolerance in kenaf. • Critical salt-responsive proteins and metabolic pathways were identified in kenaf. • Different strategies were engaged to cope with salt-stress in two kenaf cultivars. • Study lay a foundation to elucidate the molecular mechanisms of salt tolerance. Kenafis an industrial crop for natural fibers and possesses salt-tolerant characteristics that can be used for phytoremediation; however, little is known about salt-induced proteomic changes in kenaf. In the present study, a comparative cytological, physiological, and proteomic analysis was performed on a salt-sensitive (P3B) and salt-tolerant (P3A) kenaf cultivars seedlings (21d old) under salt stress. The result showed P3A has more stable ultra-structure, larger gas exchange parameters (Pn, Gs, Tr, Ci), and higher chlorophyll contents (chl a, chl b) than P3B. Furthermore, a comparative iTRAQ-based quantitative proteomic analysis showed that 89 (74.78%) and 30 (25.2%) of differentially abundant proteins (DAPs) in P3A, and 133 (69.27%) and 59 (30.7%) in P3B, were up and down-accumulated (FC > 1.5, p < 0.05), respectively. Bioinformatics analysis revealed 160 and 146 Gene Ontology (GO) categories were significantly enriched. A total of 71 and 99 DAPs were mapped to 47 and 61 KEGG pathways in P3A and P3B, respectively, and 12 KEGG pathways were determined significantly enriched for each of the two cultivars. qRT-PCR results showed that transcript levels of several randomly selected genes had consistency with abundance levels of their corresponding proteins. DAPs including ATP, α- d -glucose-1-phosphate adenylyltransferase, aldehyde dehydrogenase (ALDH), ATP dependent Clp protease (clpB), glutathione S-transferase (GST), ATP synthase, and Photosystem II subunit S (PsBS) were found significantly higher in abundance in cultivar P3A than P3B and suggested to play essential roles in response to salt stress. Inclusively, these findings could likely shed light on the molecular mechanisms of salt stress tolerance in kenaf. [ABSTRACT FROM AUTHOR]